Environmental chemistry. A review of the literature published up to mid-1980

E nviron me nt a I C he m ist ry Volume 2 A Specialist Periodical Report Environmental Chemistry Volume 2 A Review ...

Author: H.J.M. Bowen

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E nviron me nt a I C he m ist ry Volume 2

A Specialist Periodical Report

Environmental Chemistry Volume 2

A Review of the Literature published up t o m i d - I 980

Senior Reporter

.

H J. M. Bowen, Department of Chemistry, University of Reading

R eporters M. L. Berrow, Macaula y Institute for Soil Science, Aberdeen J. D. Burton, University of Southampton P. A. Cawse, AERE, Harwell D. S. P. Patterson, Central Veterinary Laboratory, Weybridge P. J. Statham, University of Southampton A. M. Ure, Macaulay Institute for Soil Science, Aberdeen

The Royal Society of Chemistry Burlington House, London, W I V OBN

British Library Cataloguingin Publication Data Environmental chemistry. - Vol. 2. - (Specialist periodical report/Royal Society of Chemistry) 1. Environmental chemistry - Periodicals I. Royal Society of Chemistry 574.5 QD31.2

ISBN 0-85 186-765-0 ISSN 0305-7712

Copyright 0 1982 The Royal Society of Chemistry

All Rights Reserved No part of this book may be reproduced or transmitted in anyform or by any means - graphic, electronic, including photocopying, recording, taping, or information storage and retrieval systems - without written permissionfrom The Royal Society of Chemistry

Printed in Great Britain by Spottiswoode Ballantyne Ltd. Colchester and London

Preface

When the first volume of this series was published in 1975, it was hoped to produce a sequel within two years. In the event a change of editorship, combined with a certain inertia, have greatly extended the publication gap beyond what was originally intended. During this period the subject has passed through successive phases of hysteria (with respect to Cd, Hg, Pb, PCBs, efc.) and grant-grabbing (a governmental response to the first phase), and has now achieved moderate respectability in the more forward-looking academic centres. It is still a young subject and there are immense areas of ignorance inviting future study. The first volume emphasized environmental organic chemistry and this second volume is deliberately slanted towards inorganic chemicals, covering the broad fields of the atmosphere and the hydrosphere, soils, and human diets. Reviewers of all these subjects agree that far too little information is available on the chemical forms of the elements in environmental reservoirs, thus laying down a challenge to analytical chemists. Patterson’s broad review of mycotoxins is included partly to redress the balance of inorganic topics and partly because his article was produced far ahead of the deadline for contributions. 0 si sic omnes! It is not proposed to segregate organic, inorganic, and physical contributions in future volumes of this series, though the editor would be glad to hear from anyone who thinks this is desirable. He would also welcome suggestions for reviews in subsequent volumes.

November 1981 H. J. M. BOWEN

Contents Chapter 1 Inorganic Particulate M a t t e r in t h e Atmosphere By P. A. Cawse

1

1 Introduction Terminology

1 2

2 Methods of Sampling and Analysis Collection Systems Filters Methods for Specific Aerosols Collection of Dry Deposition and Rainwater Total Suspended Particulates Measurement of Particle Size Determination of Atmospheric Turbidity Remote Sensing of the Atmosphere Microscopy of Dusts and Fibres Biological Sampling and Monitoring Techniques Methods of Analysis

3 3 4

3 General Physical and Chemical Composition of Particulates Background Aerosols Marine Aerosols The Stratospheric Background Urban Aerosols Inorganic Particulate-Organic Interations Particle-size Associations of Elements Photochemical and Gas-phase Reactions Atmospheric Monitoring and Surveillance Networks Trends in Atmospheric Particulate Concentrations 4 Characteristics of Emissions from Specific Sources

Resuspension of Soil Resuspension of Marine Aerosol Volcanic Emissions Forest Fires Plants Combustion of Fossil Fuels Other Industrial Processes Emission from Motor Vehicles Source Identification Studies and Methods vii

5

6 7 7

10 10 11 13 15 17 17 20 21

22 25 25 27 28

30 32 32 33 34 35 36 36 38

39 40

viii

Contents 5 Atmospheric Transport and Dispersion of Particulates Regional and Long-distance Transport Dispersion Modelling Cycling of Elements and Global Inventories

42 42 45 47

6 Removal of Particulates from the Atmosphere Dry Deposition to Land Precipitation Scavenging Total (Wet + Dry) Deposition The Air-Sea Interface

50 50 52 53 56

7 Effects of Airborne and Deposited Particulates Hazard to Man Air-quality Indices and Standards for Particulate Pollutants Effects on Visibility Effects on Global Albedo and Climate

57 57 61 63 64

8 Future Research Needs and Conclusions

68

Chapter 2 The Elemental Content of Human Diets and Excreta BY H. J. M. Bowen 1 2 3 4

Introduction Outline of Ingestion, Absorption, and Excretion Methodological Problems Inputs, Outputs, Deficient Concentrations, and Oral Toxicities of the Elements Group IA: Li, Na, K, Rb, Cs Group IB : Cu, Ag, Au Group IIA: Be, Mg, Ca, Sr, Ba, Ra Group IIB : Zn, Cd, Hg Group IIIA: B, Al, Sc, Y, Lanthanides, and Actinides Group IIIB: Ga, In, T1 Group IVA: Ti, Zr, Hf Group IVB: Si, Ge, Sn, Pb Group VB: P, As, Sb, Bi Group VIB: S, Se, Te, Po Group VIIB: F, C1, Br, I Transition Metals of Groups V-VII: V, Nb, Ta; Cr, Mo, W; Mn, Re Transition Metals of Group VIII: Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt 5 Summary

70 70 70 72 82 82 83 83 84 86 87 87 87 88 89 90 91 92 93

Contents

ix

Chapter 3 The Elemental Constituents of Soils ByA. M. Ure andM. L. Berrow

94

1 Introduction

94

2 The Alkali Metals: Lithium, Sodium, Potassium, Rubidium, and Caesium Geochemistry Weathering and Mobility Soil Contents

96 96 97 97

3 The Alkaline Earth Elements: Beryllium, Magnesium, Calcium, Strontium, and Barium Beryllium Geochemistry Weathering and Mobility Soil Contents Magnesium Geochemistry Weathering and Mobility Soil Contents Calcium Geochemistry Weathering and Mobility Soil Contents Strontium Geochemistry Weathering and Mobility Soil Contents Barium Geochemistry Weathering and Mobility Soil Contents

101 101 101 101 101 102 102 102 102 103 103 104 104 105 105 105 105 106 106 107 107

4 Titanium, Zirconium, and Hafnium Titanium Geochemistry Weathering and Mobility Soil Contents Zirconium Geochemistry Weathering and Mobility Soil Contents Hafnium Geochemistry Soil Contents

108 108 108 108 109 109 109 110 111 111 111 111

Contents

X

5 Vanadium, Niobium, and Tantalum Vanadium Geochemistry Weathering and Mobility Soil Contents Niobium Geochemistry Soil Contents Tantalum Geochemistry Soil Contents

111 111 111 112 112 113 113 113 114 114 114

6 The Lanthanides or Rare Earth Elements, and Yttrium and Scandium The Lanthanides and Yttrium Geochemistry Weathering and Mobility Soil Contents Scandium Geochemistry Weathering and Mobility Soil Contents

114 114 114 115 116 118 118 118 118

7 Molybdenum and Tungsten Geochemistry Weathering and Mobility Soil Contents

119 119 120 120

8 Chromium, Manganese, Iron, Cobalt, and Nickel

123 123 123 123 123 125 125 126 126 129 129 129 130 131 131 131 132 133 133 134 134

Chromium Geochemistry Weathering and Mobility Soil Contents Manganese Geoc hemistry Weathering and Mobility Soil Contents Iron Geochemistry Weathering and Mobility Soil Contents Cobalt Geochemistry Weathering and Mobility Soil Contents Nickel Geochemistry Weathering and Mobility Soil Contents

Contents

xi

9 Copper, Zinc, and Cadmium Copper Geochemistry Weathering and Mobility Soil Contents Zinc Geochemistry Weathering and Mobility Soil Contents Cadmium Geochemistry Weathering and Mobility Soil Contents 10 The Noble Metals Silver Geochemistry Weathering and Mobility Soil Contents Gold and the Platinum Metals Geochemistry Weathering and Mobility Soil Contents 1 1 Mercury Geochemistry Weathering and Mobility Soil Contents 12 Boron, Aluminium, Gallium, Indium, and Thallium Boron Geochemistry Weathering and Mobility Soil Contents Aluminium Geochemistry Weathering and Mobility Soil Contents Gallium Geochemistry Weathering and Mobility Soil Contents Indium Geochemistry Weathering and Mobility Soil Contents Thallium Geochemistry Weathering and Mobility Soil Contents

136 136 136 136 138 139 139 139 140 143 143 143 143 146 146 146 146 147 147 147 148 149 150 150 151 15 I 155 155 155 156 156 157 157 158 158 159 159 160 160 161 161 161 161 162 162 162 162

Contents

xii 13 Carbon, Silicon, Germanium, Tin, and Lead Carbon Geochemistry Weathering and Mobility Soil Contents Silicon Geochemistry Weathering and Mobility Soil Contents Germanium Geochemistry Weathering and Mobility Soil Contents Tin Geochemistry Weathering and Mobility Soil Contents Lead Geochemistry Weathering and Mobility Soil Contents

162 162 162 163 163 164 164 164 165 166 166 166 166 167 167 167 167 168 168 168 169

14 Nitrogen, Phosphorus, and Sulphur Nitrogen Geochemistry Weathering and Mobility Soil Contents Phosphorus Geochemistry Weathering and Mobility Soil Contents Sulphur Geochemistry Weathering and Mobility Soil Contents

173 173 173 173 174 175 175 175 175 176 176 176 177

15 Hydrogen and Oxygen Hydrogen Geochemistry Weathering and Mobility Soil Contents Oxygen Geochemistry Weathering and Mobility Soil Contents

179 179 179 179 179 179 179 180 180

...

Contents

xi11

16 The Halogens: F, Cl, Br, and I

Fluorine Geochemistry Weathering and Mobility Soil Contents Chlorine Geochemistry Weathering and Mobility Soil Contents Bromine Geochemistry Weathering and Mobility Soil Contents Iodine Geochemistry Weathering and Mobility Soil Contents 17 Arsenic, Selenium, Antimony, and Bismuth Arsenic Geochemistry Weathering and Mobility Soil Contents Selenium Geochemistry Weathering and Mobility Soil Contents Antimony Geochemistry Soil Contents Bismuth Geochemistry Soil Contents 18 Thorium and Uranium Geochemistry Weathering and Mobility Soil Contents 19 Radionuclides 20 Organic Soils 21 Conclusions

Chapter 4 Mycotoxins By 0.S. P. Patterson

180 180 180 18 1 182 183 183 183 183 184 184 185 185 186 186 186 186 188 188 188 188 189 19 1 19 1 192 192 194 194 194 195 195 195 196 196 196 197 199 20 1

203 205

1 Introduction

205

2 Biogenesis of Mycotoxic:

206

Contents

xiv

3 The Importance of Mycotoxins in the Environment Mycotoxins in Food and Feeds Toxicological Potencies of Mycotoxins General Attributes of Mycotoxic Disease Clinical Diseases of Farm Animals Caused by Mycotoxins Human Mycotoxicosis

209 209 209 212 213 213

4 Analysis of Mycotoxins The Analytical Problem Sampling Procedures Analytical Methods 5 Occurrence in Food and Animal Feed Contamination Resulting from Direct Fungal Attack Indirect Contamination of Food

216 216 217 218 22 1 22 1 223 224 2 24 227 227 229 229 230 230 23 1 23 1 23 1 23 1 232 233 233

6 Metabolism and Mode of Action of Mycotoxins

Metabolic Activation and Detoxification Reactive Toxin Molecules Aflatoxin and Related Compounds Ochratoxin A T2-toxin and Related Trichothecenes Zear alenone Metabolism and Toxic Residues 7 Control of Mycotoxins in the Food Chain Genera1 Control of Fungal Infection Control by Selection Detoxification of Aflatoxin Promising Decontamination Processes Mycotoxins other than Aflatoxin

Chapter 5 Occurrence, Distribution, and Chemical Speciation of some Minor Dissolved Constituents in Ocean Waters By J. D. Burton and P. J. Statham 1 Introduction 2 Individual Elements C aesium Barium Aluminium Thallium Germanium Tin Lead Arsenic Antimony

234 234 235 235 235 237 238 238 238 238 240 242

xv

Contents

Bismuth Selenium Iodine Zinc Cadmium Mercury Vanadium Chromium Manganese Iron Cobalt Nickel Copper Molybdenum Silver Gold 3 Additional Aspects of Chemical Speciation

Author I ndex

242 242 244 246 249 250 25 2 252 25 3 257 259 25 9 260 263 26 3 263 263 26 7

1 Inorganic Particulate Matter in the Atmosphere ~~

BY P. A. CAWSE

1 Introduction Inorganic particulate matter that is raised to the atmosphere by both natural and artificial (anthropogenic) sources is mainly distributed in the lower troposphere. The upper boundary of the troposphere, the tropopause, is found at 11-17 km above the earth's surface depending on latitude. Volcanic eruptions may inject particles through the tropopause boundary to the stratosphere, which extends to the stratopause at -SO km altitude. Interplanetary debris from micrometeors may also provide a small contribution to particle loads in the atmosphere. Particulates in the stratosphere will be subject to a global distribution, whereas material injected to the troposphere will be transported in the zonal circulation before returning to the earth's surface. These transport pathways from sources to sinks determine the local, regional, and global nature of pollution, and eventually, possible effects on biological targets.' The inorganic fraction generally comprises 80-90% of the total suspended particulates (TSP) in the atmosphere; of the remainder, benzene-saluble organic compounds may amount to 5% and biological debris, including bacterial and fungal spores, are also present. In the Antarctic aerosol practically all of the mass is attributed to SO:-,* but in a non-urban area at Chilton (Oxon) for example, 50% of TSP was accounted for by SO:-, NOT, NH;, and NaCl with a further 3% from Ca, K, and Mg:3 Fe and A1 can typically account for 2-3% of the particulate m a s 3 Potentially toxic metals such as Pb can constitute 1% in urban environments, but 0.1% in remote areas.4 Concentrations of suspended particulates in urban environments throughout the world show annual mean values between 60 and 500 pg m-3.5 The changing quality of the atmosphere in England since medieval times6 and public concern towards increasing industrial pollution demonstrate the historical importance of anthropogenic inputs to the atmosphere and disturbance to the natural background of airborne particulates. Today we are faced with changes in I

T. M. Sugden, Philos. Trans. R . SOC.London, Ser. A , 1979,290,469. W. Maenhaut and W. H. Zoller, J. Geophys. Res., 1979,842421. P. A. Cawse, AERE Harwell Report R 7669, H.M.S.O., London, 1974. W. Bach, Rev. Geophys. Space Phys., 1976, 14,429. World Health Organisation, Environ. Health Criteria 8, W.H.O., Geneva, 1979. P. Brimblecombe, J. Air Pollut. Control Assoc.. 1976. 26, 94 1. P. Brimblecombe, J . Air Polluf.Control Assoc., 1978, 28, 115.

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Environmental Chemistry

systems of energy production and manufacturing processes that will affect both the output and nature of particulate emissions. Trends in atmospheric composition must therefore be recorded to assess the impact of these changes on the environment and to decide on the need for controls on emissions. The annual consumption of coal in England and Wales is now approaching 80 million tonnes, a record level, and activities of this magnitude demand very careful assessment of environmental consequences.* Total particulate concentrations in the atmosphere and levels of associated elements of potential toxicity such as As, Cd, Pb, and Se may present a nuisance or serious hazard to man and animals by inhalation and ingestion of contaminated food. Deposition of aerosols may induce a response in soil and water ecosystems, for example by acidification and accumulation of metals. Deterioration in visibility caused by suspended particulates and their role in modification of the world climate by disturbing the transfer of radiant energy are of major concern.’ The presence of increased concentrations of water soluble ions such as SO:- and NO: in polluted aerosols may influence natural processes of nucleation.’ Hence, pollution is now being recognized as a complex international as well as a national problem. This report is aimed at broad coverage of recent advances in research on inorganic particulates in the atmosphere, mainly from 1975 onwards. Studies on the fate and effects of such materials are included. Within this remit, some 1500 references have been identified of which a selection are quoted here to demonstrate the diversity of research developments. Advances in industrial engineering techniques to control emissions and improve workroom atmospheres are extensively reviewed elsewhere. ’O-I4 Over the past 25 years, a contrast is evident between earlier localized investigations of the atmosphere and present day research projects on a global scale not only in the troposphere but also extending to the ~tratosphere.’~ Classification of papers submitted to ‘Atmospheric Environment’ from 1973-1977 has shown more emphasis on aerosol (physico-chemical) research, comprising 46% of papers, than on gaseous species (34%); atmospheric transport and modelling account for 20% and cover both particulate and gaseous forms.I6 In fact the total number of articles has increased exponentially since 1960. l 6 Research on inorganic particulates in the atmosphere, their transfer pathways and effects has now become more inter-disciplinary, demanding the efforts of meteorologists, oceanographers, agriculturists, and medical and veterinary specialists, in addition to atmospheric chemists and physicists. Terminology.-An aerosol is a system of fine solid or liquid particles in gaseous suspension, collectively referred to as ‘particulates’. Dust refers to a relatively

lo

C . England, C.E.G.B. News Letter, 112, 1980. World Meteorological Organisation. Spec. Environ. Rep. 10, W.M.O., Geneva, 1977. H. E. Hesketh. ‘Understanding and Controlling Air Pollution’, 2nd Edn., Ann Arbor, Michigan, 1974.

H. E. Hesketh. ‘Fine Particles in Gaseous Media’, Ann Arbor, Michigan, 1977. R. Dennis (ed.), ‘Handbook on Aerosols’, NTIS, Springfield, VA, 1976. l 3 L. Theodore and A. J. Buonicore, ‘Jndustrial Air Pollution, Control Equipment for Particulates’, CRC Press, Cleveland. Ohio, 1976. l 4 A. C. Stern (ed.), ‘Air Pollution’, Academic Press. New York. 1977, Vol. IV. I ’ 1 - l . W. Georgii, Pugeoph. B a s k , 1978, 116, 215. l 6 R. R. Husar,Afmos. Environ., 1979, 13, I 1 1 . I’

Inorganic Particulate Matter in the Atmosphere

3

coarse range of solid particles (diameter, d > 1 pm), produced by disintegration of minerals or from resuspension by wind when sand-blasting of soil particles may often cause comminution. Fine particles formed from the gas phase by condensation are termed ‘smoke’ and ‘fume’. In the case of fume the particles are generally from 0.01-1 pm diameter, and are often observed as agglomerates of smaller particles. Suspended particulate matter < 15 ,um diameter is usually defined as smoke. Liquid droplets are often referred to as mists (d > 40 pm) and fogs (d = 5 - 4 0 pm). Small hygroscopic particles, or condensation nuclei, are classified into Aitken nuclei (d < 0.2 p),large (d = 0.2-2 pm), and giant (d > 2 p )types. The term ‘haze aerosol’ is frequently encountered in optical studies and includes any airborne particles that affect visibility. The fundamental properties and behaviour of aerosols and their formation from gases are the subject of several texts,11,17~18 Research on aerosol electrical properties have been discussed by several authors at a recent conference. l9

2 Methods of Sampling and Analysis

Collection Systems.-Several collection systems are available for sampling ‘total’ particulates in the atmosphere by filtration, for determination of mass or detailed chemical analysis;20 the EPA High Volume sampler and the German ‘LIB’ unit21 are examples. However, errors in sampling associated with various systems and devices used out-of-doors are well r e ~ o g n i z e d . ~Errors ~ - ~ ~may result from particle impaction or diffusion to the sampling probe or inlet manifold, and from the influence of increasing wind speed on the inertia of larger particles and thus on the particle size spectrum that is collected at a given intake velocity. The intake efficiency of 17 sampling devices under outdoor conditions showed great variation for particles between 20-50 pm diameter.25 Tests on a sampler with inlet velocity of 70 cm s-I established that at wind velocities >4 m s-l, particles over 10 pm diameter were collected with < 15% efficiency: 26 sampling of this restricted range of particle size may be considered adequate if the objective is to assess respirable particles. Other workers have recommended that high volume samplers are operated inside shelters to prevent particles being deposited on2’ or blown off 28 the filter during idle hours. B e n a ~ - i concluded e~~ from laboratory tests of the EPA High Volume sampler K . Friedlander, ‘Smoke, Dust and Haze’, J . Wiley, New York, 1977. A. C. Stern (ed.), ‘Air Pollution’, Academic Press, New York, 1976, Vol. 1. l9 H. Dolezalek, R. Reiter, and H. Landsberg, ‘Electrical Processes in Atmospheres’, D. Steinkopff, Darmstadt, 1977. A. C. Stern (ed.), ‘Air Pollution’, Academic Press, New York, 1976, Vol. 111. E. Herpetz, Staub. Reinhalt. L u f , 1969, 29, 408. 22 N. A. Fuchs, Atmos. Environ., 1975, 9,697. l 3 J. P. Lodge, ‘Accuracy in Trace Analysis’, ed. P. D. La Flew, N.B.S., Washington DC, 1976, p. 3 11. 24 M. Zier, Z . Meteorol., 1977, 21, 35 1. 25 K. R. May, N. P. Pomeroy, and S . Hibbs, J . AerosolSci., 1976, 7,53. 26 N. J . Pattenden and R. D. Wiffen, Atmos. Environ., 1977, 11,677. H. S. Chahal and D. J. Romano, J. Air Pollut. Control Assoc., 1976. 26,885. 28 L. C. Thanukos, J. A. Taylor, and R. E. Kary, J . Air Pollut. ControlAssoc., 1977, 21, 1013. l9 M.M. Benarie, Atmos. Environ., 1977, 11, 527. ” S.

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under turbulent rather than laminar air-flow conditions, that outdoor sampling can be achieved without significant distortion of the size spectrum of urban particulate matter that is collected. Special procedures are required for certain types of aerosol. Mercer 30 describes a technique for collection of sulphuric acid mist and particles emitted by copper smelters. For Saharan dust an isokinetic sampler is proposed, which is battery with an efficiency > 90% for operated and collects by electrostatic pre~ipitation,~’ most particle^.^' To separate fibrous material from spherical particulates, the aerosol can be electrically charged and separated in an electric mobility spectrometer, when fibres show high mobility.33An impingement sampler has been designed to collect salt aerosols at maritime locations or from cooling tower drift near to power stations.34 Stratospheric aerosols have been collected by balloon-borne equipment designed to impact particles on carbon or copper films for subsequent electron m i c r o ~ c o p y , ~ ~ or by direct photoelectric counting of particles in sit^.^^ Measurements by both techniques have been c~mpared.~’ Collection of large (d > 50 pm) cosmic dust particles was made by balloon-borne apparatus at an altitude of -30 km.38 Development of personal air samplers has continued and is reviewed by Wallace.39General approaches to air sampling for occupational hygiene purposes are discussed by M o l y n e ~ x A .~~ miniature prototype personal dust sampler, the ‘CIP’, is based on the annular impaction principle within a rotating housing to achieve separation into respirable and non-respirable particle^.^' Another prototype instrument relies on the particle charging principle and was originally designed for detection of fire hazard in mines by spontaneous combustion: it is adapted for continuous monitoring of submicrometre particles in ambient air and is portable.42 Two types of self-contained personal samplers are available to measure respirable and non-respirable fractions of dust in quarries.43 Filters.-The selection of filters for collection of air particulates must take into account not only collection efficiencies and effects of loading on flow rates but also interferences from metals present in the filter medium and its hygroscopic nature. These properties must be considered in relation to the objectives of the sampling ~ acetate, glass fibre, and polytetrafluoroand the method of a n a l y ~ i s .Cellulose ethylene filters showed higher efficiencies (> 99%) for ambient dust particles C. J. Mercer, ‘Proc. 4th Joint Conf. Sensing Environ. Pollutants’, Am. Chem. SOC.,Washington DC, 1978, p. 34. 3 1 B. Steen, ‘Saharan Dust’, ed. C. Morales, J. Wiley, New York, 1979, p. 279. 32 B. Steen, Atmos. Environ., 1977, 11,623. 3 3 G. Zebel, D. Hochrainer, and C. Boose, J . Aerosol Sci., 1977,8, 205. 34 B. C. Moser, ‘Cooling Tower Environment’, NTIS, Springfield, VA, 1975, p. 353. E. K. Bigg, J. A m o s . Sci., 1975, 32,910. 36 D. J. Hoffmann, J. M. Rosen, and T. J. Pepin, Rep. DOT-TSC-OST-74-15, NTTS, Springfield, VA, 1974. 37 J. L. Gras, Nature (London), 1978, 271,23 1. 38 R. Wlochowicz, C. L. Hemenway, D. S. Hallgren, and C . D. Tackett, Can. J . Phys., 1976, 54, 3 17. 39 L. Wallace, in ref. 30, p. 390. 40 M. K. Molyneux, Safety Surveyor, 1977, 5, 11. 4 1 P. Courbon, ‘Atmospheric Pollution 1978’, ed. M. M. Benarie, Elsevier, Amsterdam, 1978, p. 83. 4 2 C. D. Litton, M. Hertzberg, and L. Graybeal, in ref. 30, p. 712. 43 Health and Safety Executive, ‘Airborne Dust in Quarries’, H.M.S.O., London, 1976. 30

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than nucleopore (0.8 pm) and Whatman 41 cellulose filters, which were 72% and 64% efficient at a face velocity of 49 cm s - ’ . ~Although ~ the collection efficiency of cellulose fibre filters increases markedly with loading, other types of filter are preferred for retention of Pb in urban aerosol if only light loadings are c o l l e ~ t e d .In ~ ~fact, Whatman 1 and 40 grade cellulose filters approached 100% efficiency after 24 hours collection of the ambient aerosol at Stevenage, UK,46but this was dependent on particle size and face velocity. In the Cleveland USA environment, a side-by-side comparison of total suspended particulate retained by Whatman 41 cellulose filters with glass fibre filters showed no difference at 16 sampling sites operated for 13 months.47 The collection of aerosols by nuclepore filters has been reviewed by M a n t ~ n ~ * * ~ ~ with respect to impaction, interception at the pore orifice, and diffusion by Brownian motion both to the filter face and to the walls of the pores. Problems of pore clogging have been investigated by both theoretical and experimental appro ache^.^^^ 5 1 Two modes of clogging are recognized, namely uniform pore filling and cap formation, the latter being pred~minant.~’ Evaluation of four types of glass filters for high-volume air sampling revealed small differences in collection of TSP and Pb, but large variations in SO:- and NO, : catalytic oxidation of SO, and NO, on the filter surface was suspected.s2This reaction may add 64% to true SO:- levels and 5% to TSP; because filter alkalinity is implicated, use of the neutral pH quartz fibre type is advised if glass fibre must be used.53 Methods of generation of fine particle aerosols (d < 3.5 pm) for research and calibration purposes are the subject of a symposium-revie~.~~ The practice of collection and storage of aerosols in aluminized mylar bags prior to analysis may lead to loss of submicrometre particles by electrostatic precipitation, but this can be alleviated by the use of antistatic agents.ss

Methods for Specific Aerosols.-Techniques for collection of sulphate aerosols prior to determination of total SO:- or sulphate species are summarized by B l ~ k k e r ,with ~ ~ a review of the behaviour of sulphates in the atmosphere. The problem of SO, conversion to SOP during sampling is insignificant if filters of PTFE microfibre or matrix are used, or alternatively, acid-treated quartz filtemS7 W. John and G . Reischl, Atmos. Environ., 1978, 12, 2015. B. Biles and J. McKellison, Atmos. Enuiron., 1975,9, 1030. 46 P. Clayton, Rep. LR 280(AP), Warren Spring Lab., Stevenage, Herts, 1978. 4’ H. E. Neustadter, S. M. Sidik, R. B. King, J. S. Fordyce, and J. C. Burr, Atmos. Environ., 1975, 9, 101. M. J. Manton, Atmos. Environ., 1978, 12, 1669. 49 M. J. Manton, Atmos. Environ., 1979, 13, 525. 5 o K . R. Spumy, J. Havlova, J. P. Lodge, E. R. Ackermann, D. C. Sheesley, and B. Wilder, Staub. Reinhalt. Luji., 1975, 35, 77. ” K. C. Fan, C. Leaseburge, Y. Hyun, and J. Gentry, Atmos. Environ., 1978, 12, 1797. 5 2 S. Witz and R. D. MacPhee, J. Air Pollut. Control Assoc., 1977, 27, 239. W. R. Pierson, R. H. Hammerle, and W. W. Brachaczek, Anal. Chem., 1976,48, 1808. J4 B. Y. H. Liu (ed.), ‘Fine Particles’, Academic Press, New York, 1975. 5 5 G . Cooper, G . Langer, and J. Rosinski, J. Appl. Meteorol., 1979, 18, 57. ” P . C. Blokker, CONCAWE Rep. 7/78, Den Haag, 1978. J 7 R. L. Tanner, R. Cederwall, R. Garber, D. Leahy, W. Marlow, R. Meyers, M. Phillips, and L. Newman, Atmos. Environ., 1977, 11, 955. 44

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The use of glass fibre filters to sample particulate NO; is beset with interferences from gaseous N compounds, mainly HONO, and NO,.58This is more serious than Of several types of filters tested for accumulation the formation of artifact of artifact NO; only a teflon type (‘Fluoropore’) gave negligible error.6o Determination of particulate and vapour-phase arsenic has been made by using a nuclepore pre-filter to retain particulate As and impregnated cellulose fibre filters to absorb As vapour; collection efficiencies were established with arsenic trioxide vapour.61 From measurements in the ambient atmosphere, most As was in the particulate form.61 A similar scheme was reported for determination of particulate and gaseous Br, C1, and I;62 low uptake of gaseous halogens by the nuclepore pre-filter is an advantage when sampling in remote continental regions where the gaseous halogens exceed particulate forms by two orders of magnitude. A sampling technique has been devised to permit collection of particulate (organic + inorganic) and volatile organic pollutants separately for analysis.63 Methods for sampling and identification of asbestos and asbestiform minerals are given by several authors at a recent Workshop.64 The UK Health and Safety Commission65 have made recommendations for monitoring asbestos dust (chrysotile, amosite, and crocidolite) in both non-occupational and workplace environments. Collection of Dry Deposition and Rainwater.-Steen 66 has summarized current techniques for measuring dry deposition of particulates from the atmosphere by direct accumulation on flat filter plates, natural surfaces, vertical deposit gauges, or open buckets of various diameter. From a theoretical examination of the British Standard Directional Dust Gauge it was concluded6’ that chemical analysis of the deposit would help to identify different sources and their strengths: the gauge is strongly directional. A method of short-term dustfall measurement was developed to study nuisance levels up to 1.2 km from a cement plant, to relate to complaints by residents: monthly operated gauges were misleading and inappropriate for this purpose.68 Rainwater is most frequently collected together with the dry deposition to the funnel, and in many cases deliberately, to represent the total (wet + dry) deposition to the ground. To exclude the dry deposition, various mechanical devices are now available that incorporate a moisture sensor to trigger exposure of the rain collector ’O Results from one such device, originally only when precipitation C. W. Spicer and P. M. Schumacher, Atmos. Enuiron., 1979, 13,543. R. W. Coutant, Environ. Sci. Technol., 1977, 11, 873. “ B. R. Appel, S. M. Wall, Y. Tokiwa, and M. Haik, Atmos. Environ., 1979, 13, 319. 6 1 P. R. Walsh, R. A. Duce, and J. L. Fasching, in ref. 9. p. 140. 6 2 K. A. Rahn, R. D. Borys, and R. A. Duce, in ref. 9, p. 172. 63 W. Cautreels and K. van Cauwenberghe, Atmos. Environ., 1978, 12, 1133. 64 C. C. Gravatt, P. D. La Fleur, and K. F. J. Heinrich, Natl. Bur. Stand. ( U S . ) ,Spec. Publ., 1978, 506. 65 Health and Safety Commission, ‘Asbestos. Measuring and Monitoring Asbestos in Air’, H.M.S.O., London, 1978. 66 B. Steen, in ref. 3 1, p. 287. 67 A. W. Bush, M. Cross, R. D. Gibson, and A. P. Owst, Atmos. Environ., 1976, 10,991. R. H. Williamson, J. H. Erkins, and A. Cantrell, in ref. 41, p. 175. 6 9 H . L. Volchok and R. T. Graveson, ‘Proc. 2nd Fed. Conf. Great Lakes’, Great Lakes Basin Commission, 1976, p. 259. D. G. Benham and K. Mellanby, Weather, 1978, 33, 151. 5n

J9

’”


7

developed to separate wet and dry deposition of radioactive fallout71 have been obtained by operation for one year at Chilton, Oxon, with monthly sample changes72(see also Section 6, Total Deposition). Special apparatus is described to collect rainwater in forests, as throughfall and ~ t e m - f l o w . ~ ~ Total Suspended Particulates.-Standard methods for sampling and measuring total suspended particulate matter (TSP) are listed in a manual issued by the W.H.0.74 to encourage their use and thereby assist comparisons of data from worldwide networks of monitoring stations. Three methods are based on gravimetry, and employ pre-weighed glass fibre filters. They are suitable for standard 24 h sampling periods and are (i) a high-volume method with constant flow, (ii) an EPA high-volume method, constant flow not maintained, and (iii) an OECD method, modified by the British Standards Institute. Two photometric methods are described, using sampling periods from 1-24 h:74the soiling of glass fibre or cellulose filters is measured in a reflectometer. Improved accuracy in weighing particulates collected on cellulose and other filters is obtained by using a constant temperature and humidity chamber for all handling operation^.^^ Comparative studies with filter tape samplers, whereby the thickness of particulate deposit is measured by attenuation of beta-radiation, prove the value of this technique to measure short-term (3 h) concentrations of TSP.76 A semicontinuous beta-monitor (Philips 9790) has been successfully used by B e t ~ a r i e . ~ ~ Infrared extinction has been applied to measurement of aerosol mass this method requires concentration, at wavelengths between 9 and 12 knowledge of the average refractive index and mass density of particles, but extinction is independent of particle size distribution at the selected wavelengths. Measurement of Particle Size.-Various aspects of particle size analysis are presented in a series of conference papers, which includes a description of standard particulate reference materials for checking and calibration purposes.78 Determination of particle-size distributions by impactor devices is reviewed by S h a ~ . ~ ~ Operational difficulties with high-volume cascade impactors occur mainly from particle bounce effects that cause displacement from the impaction surface to the smaller size stages of the collector.80-82Modifications to the design of cascade impactors to improve performance have been proposed and tested.83 Wangens4

’I

R. S. Cambray, E. M. R. Fisher, L. Salmon, and W. L. Brooks, AERE Harwell Report R 5898,

H.M.S.O., London, 1970. P. A. Cawse, ‘Inorganic Pollution and Agriculture’, H.M.S.O., London, 1980, p. 22. 7 3 J. D. Miller and H. G. Miller, Lab. Practice, 1976, 25, 850. 74 W.H.O., ‘Selected Methods of Measuring Air Pollutants’, World Health Organisation, Geneva, 1976. 7s J. Strand, T. Stolzenberg, and A. W. Andren, Atrnos. Environ., 1978. 12. 2027. 76 S. Dalager, Atrnos. Environ., 1975, 9, 687. 77 P. Chylek, J. T. Kiehland, and M. K. W. KO, Atmos. Enniron., 1979, 13, 169. 7 8 M. J. Groves, ‘Particle Size Analysis’, Heylen, London, 1978. 79 D. T. Shaw, ‘Fundamentals of Aerosol Science’, J. Wiley, New York, 1978. T. Allen, ‘Particle Size Measurement’, 2nd Edn., Chapman and Hall, London, 1975. P. R. Walsh, K. A. Rahn, and R. A. Duce, Atrnos. Environ., 1978, 12, 1793. 82 A . K. Rao and K. T. Whitby, J . Aerosol Sci., 1978,9, 77. 83 G. J. Newton, 0. G. Raabe, and B. V . Mokler, J . Aerosol Sci., 1977,8, 339. 84 L. E. Wangen, J . Air Pollut. Control Assoc., 1978, 28, 5 5 . 72


8

coated nuclepore (polycarbonate) filters with grease to reduce particle bounce on impaction and obtained a multi-element analysis of the particulates without interferences except for C1 and Cr. Investigations on bounce-off and wall-loss of fly ash particles sampled by a seven-stage impactor are reported;85the use of scanning electron microscopy to confirm impactor sizing data is advised, particularly for particles collected on the final ‘backup’ filter. Alterations to the sampler inlet and stages of an Andersen cascade impactor are described 86 that improve the collection of larger particles by reducing the effects of wind and turbulence, and reduce wall losses from 32% to 9% for test particles of 10 ,um diameter. A cascade quartz crystal microbalance has been used to measure the size The crystal micdistribution of particulates from a rocket exhaust robalance is basically a cascade impactor with a piezo-electric crystal as an impinging surface.88A decrease in resonant frequency occurs as the deposited mass increases and subsequently, scanning electron microscopy may be carried out on particles adhering to the face of the crystals. The great sensitivity of this instrument means that a sampling time of 6 min is adequate at TSP loadings of 50-100 ,ug m-3

89

As an alternative to cascade impactors, centrifugal particle-size separators (cyclones) have been adapted to high-volume measurements, with continuous operation for a week in urban atmospheres to obtain five size fractions.90 For measurement of specific particle-size ranges, the application of inertial, diffusion, optical, and electrical methods, and statistical treatment of data are the subject of recent b o o k ~ . ’ *The * ~cloud ~ ~ ~condensation ~ nucleus (CCN) fraction of TSP has been measured by a real-time aircraft borne detector to evaluate the effect A modified of CCN (d = 0.01-1 ,um) on cloud microstrilcture and precipitati~n.~~ Aitken nucleus (AN) counter that will operate automatically has been developed for the NASA Global Atmospheric Sampling Programme: it can detect particle - ~has’been used at flight altitudes between 6 and concentrations of < 10 AN ~ m and 13 km.93 The instrument is calibrated against a Pollak (photoelectric nucleus) counter. The integrating nephelometer can provide continuous measurement of particle mass in the accumulation mode, within the size range 0.1-2 pm, by relating light scattering to TSP.94p9 5 In the Chicago environment the light scattering coefficient was highly correlated with particulate weights in the size range 0.38-1.3 ,um obtained by cascade impactor, and was independent of humidity.96 The nephelometer is suited to short-term measurements of peak concentrations of airborne

particulate^.^^ J. M. Ondov, R. C. Ragaini, and A. H. Biermann, Atmos. Environ., 1978, 12, 1175. A. R. McFarland, J. B. Wedding, and J. E. Cermak, Armos. Environ., 1977, 11, 535. 87 R. L. Chuan and D. C. Woods, in ref. 30, p. 610. 88 J. R. McNesby, ‘Proc. Int. Symp. Recent Advances in Assessment of Health Effects of Environmental Pollution’, Rep. EUR 5360, C.E.C., Luxembourg, 1975, p. 1371. 89 R. L. Chuan, in ref. 54, p. 763. 90 D. M. Bernstein, M. T. Kleinman, T. J. Kneip, T. L. Chan, and M. Lippmann, J . Air Pollut. Control Assoc., 1976, 26, 1069. 91 R. D. Cadle, ‘The Measurement of Airborne Particles’, J. Wiley, New York, 1975. 92 V. K. Saxena and N. Fukuta, ‘Proc. Int. Conf. Cloud Phys.’, Boulder, CO, 1976, p. 607. 93 T. W. Nyland, N.A.S.A. Tech. Paper 1415, 1979. 94 A. G . Clarke, M. A. Moghadissi, and A. Williams, J . Aerosol Sci., 1977, 8, 73. 8s 86


9

Separate collection of non-respirable and respirable fractions of ‘I’SP suitable for elemental analysis has been achieved by using two nuclepore filters in series, with pore diameters of 12 pm and 0.2 pm, respectively, at 12.7 cm s-’ face velocity for acceptable collection effi~iency.~’ Coarse and fine fractions of the TSP have been collected by a two-stage impactor suitable for on-line measurements, based on the beta-attenuation principle.98 The ‘anthropogenic’ fraction of TSP has been derived from analysis of air-filter deposits for C1 and Si to eliminate the contribution from soil dust, and is claimed to show better correlation with public concern and reduction in v i ~ i b i l i t y . ~ ~ Continuous measurement of carbonaceous particles is reported using a spectrophone to measure their light absorption.Io0 The absorption coefficient for aerosols of graphitic carbon type (rather than natural ‘organic’ type) is 17 m2 g-’ carbon at 416.6 nm, employing a helium-cadmium laser source.1ooSizing of single particles by laser interferometry using a cross beam laser velocimeter is described by Roberds,lo1and relies on forward scattering of light by the particle to obtain size information by means of data-inversion methods. lo2 Submicrometre particle size distributions have been determined by application of three continuous integral aerosol sensors, namely a condensation nucleus counter, an electrical aerosol charger, and an integrating nephelometer to measure the number, surface, and volume parameters of the aeros01.l~~ The authors apply a special data-inversion procedure to derive the particle-size distribution. Subsequently, this method was used to study power station plumes.’o4 Recent types of Knollenberg (light scattering) aerosol counters have been evaluated with monodisperse test aerosols in the size range 0.1-10 pm, with the conclusion that resolution was poor for particles >0.5 pm radius.lo5 Other laboratory and field tests on optical particle counters indicated that frequent calibration is necessary, but agreement was generally good for submicrometre particles.lo6Ilo’ Calibration in the field is possible with a specially designed inertial impactor. lo* A particle-size spectrometer supplemented by a microcomputer can obtain a differential size distribution for the ambient aerosol over 19 intervals of equal logarithmic size from 0.3-11 pm diameter, with the option to select a number, surface, or volume representation.lo9 J. C. Kretzschrnar, Atmos. Environ., 1975, 19, 931. P. A. Scheff and R. A. Wadden. Atmos. Environ., 1979. 13,639. 97 R . D. Parker, G. H. Buzzard, T. G . Dzubay, and J. P. Bell, Atmos. Environ., 1977, 11,617. 98 E. S. Macias and R. B. Husar, ‘Proc. 2nd Int. Conf. Nucl. Methods Environ. Res.’, J. R. Vogt and W. Meyer (ed.), Univ. Missouri, 1974, p. 4 13. 9’) D. A. Levaggi, J . S. Sandberg, M. Feldstein, and S. Twiss, J. Air Pollut. Control Assoc., 1976, 26, 554. T. J. Truex and J. E. Anderson, Atmos. Environ., 1979, 13, 507. ‘‘I D. W. Roberds, Appl. Optics, 1977, 16, 1861. A. L. Fymat, in ref. 30, p. 7 19. G. M. Sverdrup and K. T. Whitby, Environ. Sci. Techno[.,1977, 11, 117 1. lo4 G. M. Sverdrup, Atmos. Environ., 1978, 12, 2005. Io5 R. G. Pinnick and H. J. Auvermann, J. Aerosol Sci., 1979, 10,55. ‘06 E. E. Hindman, G . L. Trusty, J . G. Hudson, J . W. Fitzgerald, and C. F. Rogers, Atmos. Environ., 1978, 12, 1195. lo’ J . Kruger and A. H. Leuschner, Atmos. Enoiron., 1978, 12, 201 1. V . A. Marple and K. L. Rubow, J. Aerosol Sci., 1976, 7,425. lo’) C. W. Lewis and P. J. Lamothe, J. Aerosol Sci.,1978, 9, 39 1. 95

96


10

Analysis of particle size and shape by holography has been further developed by introduction of new systems for automatic analysis of three-dimensional aerosol images, to overcome tedious manual recording Determination of Atmospheric Turbidity.-Measurement of the integrated aerosol content of the atmosphere has been made for many years by sun photometers and pyrheliometers. A new sun photometer is now proposed to improve reliability, and typical errors experienced with current apparatus using 380 nm and 500 nm filters are summarized.112It is recognized that the pyrheliometric method is the most stable and is best for recording low turbidities at baseline stations."* Several types of sun photometers were intercalibrated and applied to measurement of dust in the Saharan air layer over the N. Atlantic ocean: the turbidity data was examined in relation to mineral and sea salt components of particulates collected on air filters at ground l e ~ e 1 . lSahara ~~ dust episodes at Monte Cimone and Sestola, Italy, have been measured with Volz sun photometers operated at four wavelength intervals, and related to particle-size spectra at ground level.114The authors conclude that the large particle mode (radii 0.3-1.2 pm) is mainly responsible for wide variations in optical thickness of the atmosphere. Relationships between the physical properties of the atmosphere and the angular and total scattering of light by haze aerosols are reported by McCa~tney."~ A valuable list of measurements of scattering in the free atmosphere is classified into optical probing, contrast and visibility, and day sky radiance.'I5 Remote Sensing of the Atmosphere.-Satellites have been used to observe the source and trajectories of haze, soil dust, volcanic debris, factory plumes, and smoke from forest fires. The geostationary orbiting satellites (SMS/GOES system) operated by the US National Oceanic and Atmospheric Administration provide visible imagery and infrared data, and Parmenter116 describes results from two satellites operating over the equator at 135O W and 75 OW. Studies of smoke plumes by the general purpose LANDSAT-1 satellite can cover a large area of country in great detail, with a resolution of -70 m.117*'18 Differences in absorption by aerosol in the plumes are detected by a multi-spectral scanner that operates over four wavebands."' LANDSAT images of the UK have been analysed at the University of East Anglia;Il8 problems of distinguishing plumes from clouds have received special attention. Developments in high-power tunable lasers covering the range -400-40 pm have led to increasing application to optical spectroscopy for monitoring both

I"

R. Bexon, J. Gibb, and G. D. Bishop, J. Aerosol Sci.,1976, 7, 397. J. D. Trolinger, U.S. Environ. Prot. Agency Rept 600/2-79/005. 1979.

lI3

J. M. Prospero, D. L. Savoie, T. N. Carlson, and R. T. Nees, 'Proc. 1 Ith Tech. Conf. Hurricanes and

'lo

C. Frohlich, in ref. 9, p. 12 and p. 89.

'I4 'I5 'I6 11' ll*

Tropical Meteorol.', Am. Meteorol. SOC.,Boston, MA., 1978, p. 163. C. Tomasi, F. Prodi, and F. Tampieri, Beit. Physik. Atmos., 1979, 52, 215. E. J . McCartney, 'Optics of the Atmosphere-Scattering by Molecules and Particles', J. Wiley, New York, 1976. F. C. Parmenter, in ref. 30, p. 254. T. T. Alfoldi, in ref. 30, p. 258. P. Brimblecomhe, A. Armstrong, and T. Davies,J. Br. Interplaner. Soc., 1978, 31, 11.


11

particulate and gaseous pollutants.119 An airborne down-looking lidar (light detection and ranging) is advantageous for research on plume dispersion. l Z o Zuev”’ refers to two simultaneously operating lidars, one ground based and the other airborne, to record vertical profiles of the volume backscattering and total scattering co-efficients and their ratio (lidar ratio value). Heighthime cross-sections of the aerosol over Munich have been recorded by an airborne Nd-glass laser at 1.06 A mobile ground-based ruby laser radar unit has been developed for particulate dispersion measurements. lZ3 Basic principles of measurements by lidar and the ‘DIAL’ system (differential absorption lidar), which employs a pulsed tunable laser source to obtain long path absorption data, are discussed by Svanberg. lz4 Remote sensing and characterization (complex refractive index and size distribution) of stratospheric aerosols by lidar, by a dustsonde (balloon-borne optical counter), and by satellite-borne photometer have been discussed at a recent Workshop.125Temporal and spatial variations in the stratospheric aerosol detected by lidar are shown to respond to meteorological influences and extension of this technique to observe stratospheric-tropospheric interchange of aerosols is proposed. 126 With a ground-based ruby lidar system, the backscattering from aerosols is obtained by comparing the total backscattering profile with the expected return from the dominant molecular component in the atmosphere. 127.128 Fluctuations in the stratospheric aerosol load from 1970- 1977 are discussed with special reference to particles of volcanic and extra-terrestrial origin,lZ9as observed by lidar. Iwasaka 130 used a two-colour lidar at A 0.6943 pm and 1.06 pm to record the size distribution function and density of stratospheric aerosols with 0.1-1 Fm radii, assuming a refractive index of 1.42; since the measurement time is short, about 100 s, changes in vertical profiles caused by atmospheric processes can be km altitude), the existence of aerosol studied. In the mesosphere (from -50-60 layers containing N a and K are confirmed by fluorescence lidar.’31*’32 Microscopy of Dusts and Fibres.-Combinations of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray fluorescence, and

C. K. N. Patel, Science, 1978, 202, 157. A. Eckert and R. B. Evans, ‘Proc. 1 lth Symp. Remote Sensing Environ.’, Ann Arbor, MI, 1977, p.

I2O J.

353.

V. E. Zuev, Dev. Atmos. Sci., 1978, 9, 265. C. Werner, G. S. Kent, and F. Kopp, ‘Proc. 4th Symp. Meteorol. Obs. Instrum.’, Am. Meteorol. SOC., Boston, Mass, 1978, p. 197. 12’ R. M. Hoff and F. A. Froude, Atmos. Environ., 1979, 13,35. l z 4 S. Svanberg, ‘Surveillance of Environmental Pollution and Resources by Electromagnetic Waves’. ed. T. Lund, D. Reidel, Dordrecht, Holland, 1978, p. 37. 1 2 5 A. Deepak (ed.), ‘Inversion Methods in Atmospheric Remote Sounding’, Academic Press. New York. I2l

122

1977.

F. G. Fernald and B. G. Schuster, J. Geophys. Res., 1977, 82,433. 12’ P. B. Russell, V. Viezee, R. D. Hake, and R. T. H. Collis, Q.J.R. Meteorol. Soc.. 1976, 102,675. 128 R. Reiter, H. Jaeger, W. Carnuth, and M. Littfass, Dev. Atrnos. Sci., 1978, 9, 277. 129 B. R. Clemesha and D. M. Simonich, J . Geophys. Res., 1978, 83, 2403. Y. Iwasaka, J . Meteorol. SOC.Jpn., 1977, 55,457. G. Megie, F. Bos., J. E. Blamont, and M. L. Chanin, Planet. Space Sci., 1978, 26, 21. 132 B. R. Clemesha, V. W. J. H. Kirchoff, and D. M. Simonich. Planet. Space Sci., 1979, 27, 909. lz6

12


diffraction analysis have been developed to give valuable information on the depth and surface properties of particles that facilitates identification of sources.133-136 For analysis of fly ash particles, combination of SEM with energy dispersive X-ray analysis (EDXRFA) provides simultaneous colour mapping to show the spatial distribution of Ca, Fe, and K ; some 100 particles can be scanned in 3 min.I3' A similar technique was used to analyse dust particles in pulmonary tissues for Al, Ca, Fe, Mg, S, Si, and Ti.138Combination of SEM with X-ray diffraction analysis of Sahara dust enabled distinction between clay and quartz particles of diameter 0.08-7 Other applications of SEM and EDXRFA have been made to analysis of particulates collected by a piezoelectric cascade impactor, during aircraft sampling of rocket exhaust87 and volcanic plumes.140 Distinct morphological and chemical differences are related to particle size fractions. Thus in volcanic-derived aerosols impure sulphuric acid droplets were seen with some large crystals rich in A1 and Zn, and fragments of basaltic glass and p l a g i o ~ l a s e . ' ~ ~ Studies on Antarctic aerosols utilized the resolution obtained by TEM photographs for counting and sizing purposes.141X-Ray energy spectra showed that over 50% of Aitken particles (d < 0.2 pm) contained A1 and S, 35% contained Si, but few trace elements which were predominant in larger parti~1es.I~~ Particulates scavenged by snow and rain and deposited on coniferous trees have been characterized by TEM, SEM, and EDXRFA, with aggregates of small soot particles best observed by TEM.'42 Gonzales and Murr143developed a TEM method to examine particulates scavenged by single raindrops, and demonstrated that in New Mexico these particles are mainly polycrystalline aggregates of layer silicates from 0.0 1-3 pm in diameter. Quantitative analysis of SO:- in individual particles from 0.01 ,um to a few micrometers diameter is possible by collecting them on electron microscope screens and coating with BaCI,, after which the growth rings of BaSO, are recorded by TEM.144v145 A similar technique has been used to analyse non-volatile nitrates in particles >0.2 pm diameter, by reaction with nitron reagent to produce needles surrounding the particles. 146 Many improvements have been made to methods for sampling, analysis, and '~~ identification of asbestos fibres by TEM, SEM, and X-ray s p e c t r ~ m e t r y . Fibre counting and size measurements from SEM can be related to analysis of elements, H. Malissa and M. Grasserbauer, Mikrochim. Acta, 1975, No. 2,325. L. D. Hulett, H. W. Dunn, J . M. Dale, J . F. Emery, W. S. Lyon, and P. S. Murty, 'Measurement Detection and Control of Environmental Pollutants', I.A.E.A., Vienna, 1976, p. 29. R. W. Linton, P. Williams, C. A. Evans, and D. F. S . Natusch, Anal. Chem., 1977, 49, 15 14. 1 3 6 F. Parungo, E. Ackerman, H . Proulx. and R. Pueschel, Atmos. Environ., 1978, 12,929. J. B. Pawley and G . L. Fisher, J . Microsc., 1977, 110, 87. 1 3 8 A. Brody, N. V. Vallyathan, and J. E. Craighead, 'Scanning Electron Microscopy', Pt. 3, I.I.T. Research Inst., Chicago, IL., 1976, 9,477. F. Prodi and G . Fea, J . Geophys. Res., 1979,84,6951. I4"R. D. Cadle, A. L. Lazrus, B. J. Huebert, L. E. Heidt, W. 1. Rose, D. C. Woods, R. L. Chuan, R. E. Stoiber, D. B. Smith, and R. A. Zielinski, J . Geophys. Res., 1979,84,6961. I 4 l F. Parungo, E. Ackerman, W. Caldwell, and H. K. Weickmann, Tellus, 1979, 31, 521. 14* J. Gether, G. Lunde, and J. Markali, SNSF Project Res. Rep. FR 7/76, Nisk, Norway, 1976. ' 4 3 T. W. Gonzales and L. E. Murr, J . Geophys. Res., 1977, 82, 3161. 144 Y. Mamane and R. G. de Pena, Atmos. Environ., 1978, 12,69. 14' G. P. Ayers. Atmos. Environ., 1978, 12, 16 13. 146 G. P. Ayers, Atmos. Environ., 1978, 12, 1227. '41 I. J. Selikoff and D. H. K. Lee, 'Asbestos and Disease', Academic Press, New York, 1978. 13'

134

Inorganic Particulate Matter in the A tmosphere

13

e.g., Al, Ca, Fe, Mg, Na, and Si,148,149 and inter-element ratios assist identification of the main form of asbestos. In a recent comprehensive review of SEM and TEM methods applied to fibrous particles that occur in ambient air, an informative series of scanning electron micrographs is shown which includes ammonium sulphate and gypsum particles in addition to glass and asbestos Nuclepore filters of different pore diameters are preferred for sampling prior to SEM, to partially separate asbestos from larger non-fibrous particles.150 De Nee151 reported improvements in back-scattered electron imagery with SEM that can reveal asbestos microfibres of higher atomic number than organic material in the filter or lung tissue matrix. A computerized SEM system combines image analysis of fibres with EDXRFA of their chemical composition, to identify asbestos fibres from other particulate matter.ls2 The detailed particle atlas by McCrone and Delly 153 provides a unique collection of photomicrographs to assist in characterization of airborne materials from observations with SEM, TEM, and the polarizing microscope. Biological Sampling and Monitoring Techniques.-Examination of relative levels of particulate metals in the atmosphere and input to the ground by the use of plants as bioindicators and collectors has continued, often with bioassay of phytotoxic gaseous pollutant^.'^^ Apart from analysis of the indigenous flora such as epiphytic bryophytes,ls5 test plants may be exposed over definite periods (transplant technique). This method is required in many areas where pollution has eliminated the local flora. Lichens are attractive as indicator plants and the value of various species and their identification has been reviewed.lS6 Characteristics of species with respect to selective uptake of metals must be recognized, in addition to the possibility of heavy metal toxicity that could result in threshold levels for metal intake by the thalli.157 Lead concentrations in native lichens (Hypogyrnnia physodes) growing close to a motorway were one third of levels in the substrate which was bark of Pinus syluestris, and in this case it was concluded that bark sampling was a better indicator of pollution by motor vehicles up to 200 m from the road.lS8 Air pollution from metal industry at Kokkola, Finland was best indicated by accumulation of Fe, S, and Zn in indigenous epiphytic bark lichens and Zn in pine needles, but increases in V in lichens were attributed to emissions from fuel oil combustion. 159 In a subsequent study of emissions from wood pulping industry, native lichens were K. R. Spurny and W. Stober, ‘Proc. 3rd Int. Conf. Nuclear Methods Environ. Energy Res.’, USERDA, Columbia, Missouri, 1977, p. 69. 149 K. R. Spurny, W. Stober, H. Opiela, and G. Weiss, Sci. Total Environ., 1979, 11, 1. K. R. Spurny, W. Stober, E. R. Ackerman, J. P. Lodge, and K. Spurny, J. Air Pollut. Control Assoc., 1976, 26,496. P. B. De Nee, ‘Symp. Electron Microscopy of Microfibres’, M. Asher and P. P. McGrath (ed.), U.S.F.D.A., Rockville, MD, 1977, p. 68. I5*T. Werlefors, C. Eskilsson, S. Ekelund, S. Krantz, and C. Tillman, ‘Proc. Int. Symp. Control Air Pollut. Work. Environ., Stockholm, 1978, p. 255. 153 W. C. McCrone and J. G. Delly, ‘The Particle Atlas’, 2nd Edn., Ann Arbor, MI, 1973, Vol. 1 - 4 . 154 W. A. Feder, Environ. Health Perspect., 1978, 21, 139. L. Rasmussen, Environ. Pollut., 1977, 14, 37. D. L. Hawksworth and F. Rose, ‘Lichens as Pollution Monitors’, E. Arnold, London, 1976. 15’ M. R. D. Seaward, Lichenologist, 1975, 6, 158. lSB K. Laaksovirta, H. Olkkonen, and P. Alakuijala, Environ. Pollut.. 1976, 11,247. I S 9 K. Laaksovirta and H. Olkkonen, Ann. Bot. kenn., 1977, 14, 12. 14*

14


analysed for seven elements to indicate the distribution of pollutants, in preference to pine needles.160Atmospheric heavy metal pollution in the Copenhagen area was examined by analysis of epiphytic lichens (Lecanora conizaeoides), epigeic bryophytes (Brachythecium rutabulum and R hytidiadelphus squarrosus), bulk precipitation, and top regional differences in deposition isopleths found for Pb, V, and Zn showed good agreement for all media. Significant decreases in concentrations of Ca, F, Li, Se, Sr, and U were found in a terricolous lichen (Purmelia chlorochroa) along transects radiating up to 64 km from a fossil-fuel power station.16* Hypogymnia physodes is noted as more resistant to SO, than either Alectoria capillaris or Usnea ~ p p . ' ~ ~ The transplant technique for lichens usually involves removal on tree bark or branches, which are then mounted on a suitable base for placement in industrial regions. Steinnes and Krog'64 reported order of magnitude increases in Hg (from 0.4 p g g-I background) in Hypogymnia physodes after a month in urban conditions. In North-Rhine Westphalia, FRG, both lichen and rye-grass transplants were analysed. 165 Native mosses (Dicranellu heteromalla and Ceratodon purpureus) and grass (Holcus lunatus) contained 1240 and 130 pg Pb g-', respectively, as a result of pollution from a battery factory.166Hypnum cupressiforme growing within 14 km of Consett iron and steel complex in N.E. England contained high levels of Cu, Mn, Pb, and Zn in addition to Fe.I6' In Norway, Hylocomium splendens from rural sites showed 20-fold differences in accumulation of As, Pb, Sb, and Se that were directly related to precipitation,168and it is noted e l ~ e w h e r e that ' ~ ~ most metals present in moss originate from direct dustfall, precipitation, and stem-flow, since the chemical composition of moss and bark is very different (except for K). Hylocomium splendens from Polish National Parks accumulated more Cd and Cu, but less,Pb and Zn than Pleurozium hylocomium and patterns of regional pollution were e~tablished."~Emissions from a coal-fired power plant in Fort Union Basin, Montana led to significant accumulations of As in forage plants of the region including Agropyron spicatum and Artemisia cana, used as indicators of pollution. 1 7 1 The use of small moss bags for regional aerosol monitoring is recently reviewed.I7* These are prepared from specially cleaned moss from rural areas, and the bags are normally exposed for 1-6 weeks at 1.5-2 m above ground. After exposure, analysis may be made by atomic absorption following wet ashing in K. Laaksovirta and H. Olkkonen. Ann. Bof. Fenn., 1979, 16, 285. A. Andersen, M. F. Hovmand, and I. Johnsen, Enuiron. Polluf.. 1978, 17, 133. I b 2 L. P. Cough and J . A. Erdman. Bryologisl. 1977, 80,492. K. Laaksovirta and J. Silvola,Ann. Bot. Fenn., 1975, 12, 81. lh4 E. Steinnes and H. Krog, Oikos, 1977, 28, 160. I h 5 B. Prinz and G . Schull. Schrifl. Landes Nordrhein- Wesffalen, 1978, 46, 25. l h 6 J. M. Ratcliffe".Atrnos. Eni!iron., 1975, 9, 623. 1 6 7 G . Ellison. J . Newham. M. J. Pinchin. and 1. Thompson, Environ. Pollut., 1976, 11, 167. I h H E. Steinnes, Inst. Atomic Energy Rep. K R 154, Kjeller, Norway, 1977. l b 9 L. Rasmussen and I. Johnsen, Oikos. 1976, 27,483. K. Grodzinska, Water Air Soil Pollut., 1978. 9, 83. J. J. O'Toole. T. E. Wessels, and K. L. Malaby, Rep. IS-M-205. U.S. Dept. Energy, Office of Health and Environ. Res., 1978. G. T. Goodman. M. J. Inskip. S. Smith, G. D. R. Parry. and M. A. S. Burton. in ref. 3 I . p. 2 11. Ih"

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15

HNO,. 173 Mosses have a high cation-exchange capacity, therefore leaching of metals by rainfall during exposure is minimized.172Surveys in S.W. England for metals in air particulate have been made by moss bags alone,173or in combination with air filtration and a resin-impregnated material (TAK) to retain air particulate^.'^^ Moss bag exposure was able to show unsuspected areas of metal pollution, but was difficult to relate to air concentrations from filter analysis.174A similar conclusion was reached following a combined survey in the Swansea Valley, using moss bags, air filters, and dust and rainwater C10ugh’~~ reported that deposition of particles to moss bags (Hypnurn cupressiforrne) is similar to a flat surface of rye-grass and they are useful dry deposition monitors; because the collection efficiency of moss changes rapidly with particle size and is low for submicron particles, it is less valuable for monitoring concentrations of elements in air particulate than in dry deposition. Methods of Analysis.-Advances in the application of various methods to analysis of air particulates will only be referred to in brief, since detailed discussion of this topic and methodology is made e1~ewhere.l~~. 178 Several new techniques have been applied to multielement analysis of inorganic particulate material collected from the atmosphere by filters or impactor devices. These techniques can analyse specific size fractions or individual particles from such material and provide better chemical characterization to help identify natural and industrial sources of particulates in the ambient atmosphere. For example, X-ray fluorescence (XRF) analysis of trace elements has been aided by developments in semiconductor detectors. This has led to increasing application of energy dispersive X R F analysis with excitation of photons by X-rays,’79 or by bombardment of air-filter deposits with 3-5 MeV protons (particle-induced X-ray emission: ‘PIXE’). lso> Proton elastic scattering analysis (‘PESA’), using higher energy protons than PIXE, has been applied where light elements are of main concern e.g., from F to S, and reduces problems of attenuation of soft x-ray^.'^*,'^^ The sensitivity of automated energy dispersive X R F permits multielement analysis of filters exposed on high-volume air samplers for only 10-20 h.ls4 Minimum detectable limits are reported in the range 2.5-8 ng cm-’ filter for As, Br, Cd, Cu, Ga, Hg, Ni, Pb, Rb, Sb, Se, Sn, Sr, and ZII.”~ BirksIs5 concludes that energy dispersion methods are more suited to general element surveys in unfamiliar samples, while wavelength R. Gill, M. H. Martin, G. Nickless, and T. L. Shaw, Chemosphere, 1975,4, 113. L. E. Robson, ‘A Survey of Airborne Metals’, Rept. Avon Glos. Somerset Environ. Monitoring Ctee., Bath, 1977. L. E. Robson, ‘Rept. Collab. Study on Certain Elements in Air, Soil, Plants, Animals and Humans in the Swansea-Neath-Port Talbot Area’, Welsh Office, Cardiff, 1975. 1 7 6 W. S. Clough, Atmos. Environ., 1975, 9. 11 13. H. Malissa (ed.), ‘Analysis of Airborne Particles by Physical Methods’, C R C Press, Boca Raton, FL, 1978. M. Katz, J . Air Pollut. ControlAssoc., 1980, 30, 528. J. M. Jaklevic, R. C. Gatti, F. S. Goulding, B. W. Loo, and A. Thompson, in ref. 30, p. 697. T. B. Johansson, M. Ahlberg, R. Akselsson, G. Johansson. and K. Malmqvist, J . Radioanal. Chem., 1976. 32, 207. “ I J. W. Winchester, in ref. 148, p. 1. K. Kemp, in ref. 41, p. 57. J. W. Nelson, in ref. 186, p. 19. In4 P. Van Espen. H. Nullens, and F. C. Adams, Z . Anal. Chem., 1977,285,215. L. S. Birks, in ref. 186, p. 57. 174

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dispersion achieves better resolution of elements and is appropriate for routine analysis of large numbers of samples; it can also distinguish the valence and bonding of elements such as S present as sulphate, sulphite, and sulphide compounds. Problems associated with preparation of thin layer standards to calibrate X R F techniques and corrections for attenuation have been reviewed by Dzubay.lg6 Analysis of individual particles of fly ash has been made by ion microprobe mass spectrometry and auger electron spectrometry to reveal the surface predominance of Cr, Mn, Pb, and TI, which is explained by a volatilization-condensation mechanism.135The application of emission spectrographic methods to multielement analysis of air particulates is reviewed by Skogerboe.lg7With this procedure, porous cup graphite electrodes may be used as air filters and are very suitable for short sampling periods of 4-1 h in urban areas, to follow the time variation of element concentrations.I g 7 Neutron-activation analysis has been widely applied to measure some 30 to 40 elements in air p a r t i c ~ l a t e . ' ~Re ~ -cent ~ ~ ~developments include cyclic activation, using a series of neutron irradiation-transfer-count-return to irradiation system steps to allow detection of short-lived isotopes such as 207mPb(0.8 s half-life), 20F, and 77mSe.191.192 Analysis of B in addition to other elements is achieved by measurement of prompt gamma-ray emission during neutron a ~ t i v a t i 0 n . lSome ~~ laboratories have used gamma photon activation analysis to include Bi, Sn, Pb, and Zr in the suite of elements a n a 1 y ~ e d . l ~ ~ An X-ray diffraction technique can detect microgram quantities of chrysotile asbestos in respirable Infrared spectrometry has been applied to analysis of quartz dust 196 and asbestos minerals in air particulate^.'^^ Differential thermal analysis offers specific measurement of free crystalline quartz in respirable dust that contains clay minerals, as frequently collected by personal air samplers.198 For characterization of particulates from a polluted atmosphere, the use of raman spectra has been examined between 920 and 1950 ~ m - ' ; ' distinctive ~~ spectra are given by (NH,),SO,, NH,HSO,, and H,$O,, and primary particulate carbon from vehicle exhaust. However, a large fluorescence background limits general sensitivity. Newmanzoo has reviewed current methods for analysis of sulphur compounds in the atmosphere, including laser raman spectroscopy.

T. G . Dzubay (ed.),'X-ray Fluorescence Analysis of Environmental Samples', Ann Arbor, MI, 1977. R. K. Skogerboe, in ref. 23, p. 791. Ia8 L. Salmon, AERE Harwell Report R 7859, H.M.S.O., London, 1975. la9 J . Radioanal. Chem. 1977, 37, Part 2. 190 S. Amiel (ed.), 'Nondestructive Activation Analysis', Elsevier, Amsterdam, 1980. 1 9 1 N. M. Spyrou, P. Maheswaran, K. Nagy, and F. Ozek, in ref. 134, p. 15 I. I P 2 N. M. Spyrou and S. A, Kerr, J . Radioanal. Chem., 1979,48, 169. 193 G . E. Gordon, D. L. Anderson, M. P. Failey, W. H. Zoller, W. B. Walters, and R. M. Lindstrom, in ref. 148, p. 83. 194 J. S. Hislop and D. R. Williams, J . Radioanal. Chem., 1973, 16, 329. 195 B. A. Lange and J . C . Haartz, Anal. Chem., 1979,51,520. 196 J. P. Coates, Am. Lab., 1977, 9, 105. I y 7 J. P. Coates, Am. Lab., 1977, 9, 57. 198 J. P. Schelz, Thermochirn. Acta, 1976, 15, 17. 199 H. Rosen, A. D. A. Hansen, and T. Novakov, in ref. 30, p. 703. 2uo L. Newman, A m o s . Environ., 1978, 12, 113.

Ia6

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17

Continuous in situ measurement of sulphur aerosols is now possible by flame photometry with separate determination of H,SO, and its ammonium salts.201,202 Many laboratories without extensive analytical facilities require simple methods of analysis for limited investigations. A laboratory manual compiled by SCOPE 203 describes sampling and analysis of several particulate metals in air, avoiding sophisticated techniques. Further practical details are available in the book by K a t ~Eleven . ~ ~ particulate ~ metals collected on polycarbonate membrane filters have been determined by atomic absorption spectroscopy.20sA new colorimetric method for analysis of microgram amounts of SO:- in water extracts from air filters is reported, using barium-nitrosulphonazo(m) chelate.*06 To establish the accuracy of reported results, intercomparison of trace element analysis by different techniques has been made at 21 laboratories by distribution of simulated (spiked) air filter samples:207results for Hg and Mo were particularly divergent. The NBS standard fly ash reference material (SRM-1633) has now been supplemented by SRM- 1648, urban particulate matter, certified for 9 elements, which was collected from the St. Louis, Missouri, urban atmosphere.208A reference material has recently been prepared by the E.E.C. Community Bureau of Reference using air particulates collected from industrial regions of Belgium. Intercomparison of analysis of filter deposits by separate techniques showed that variability was least for As, Co, Pb, and Se, intermediate for Cr, Cu, Fe, Mn, Ni, and Zn, and largest for Cd; problems of incomplete dissolution of Cr, Fe, and Ni by wet ashing were

3 General Physical and Chemical Composition of Particulates Background Aerosols.-Research on background concentrations of aerosols in the troposphere and their composition has proceeded in several remote regions, where little interference from industrial sources is anticipated. Although it is possible to talk in broad terms of continental and maritime background aerosols in addition to rural background measurements that are often used to compare with urban pollution,210natural sources may cause wide variations in regional backgrounds and make the siting of background stations and assessment of anthropogenic influences difficult.211 The chemical composition of the aerosol near the Amundsen-Scott South Pole Station212is shown in Table 1, together with concentrations observed at other

J . J. Huntzicker, R. S. Hoffman, and C. S . Ling, Atmos. Environ., 1978, 12,83. W. G. Cobourn, R. B. Husar, and J. D. Husar, A m o s . Enuiron., 1978, 12, 89. 203 SCOPE 6, 'Environmental Pollutants, Selected Analytical Methods', Butterworth, London, 1975. 204 M. Katz (ed.), 'Methods of Air Sampling and Analysis', 2nd Edn.. Am. Publ. Health Assoc., Washington, DC, 1977. 205 B. C. Begnoche and T. H . Risby, Anal. Chem., 1975,47, 1041. *06 E. M. Hoffer, E. L. Kothny, and B. R. Appel, Amos. Environ.. 1979, 13, 303. '07 A. Tugsavul, R. Dybczynski, and 0. Suschny, Environ. Int., 1979, 2, 19. 'On Anon, Dimensions, 1979, 63, 19. '09 P. A. Cawse, AERE Harwell Report R 8191, H.M.S.O., London, 1976. 2'o P. A. Cawse, AERE Harwell Report R 9164, H.M.S.O., London, 1978. 2 1 ' E. S. Selezneva, Sou. Meteorol. Hydrol., 1978, 1, 3 1. 'I2 W. Maenhaut and W. H. Zoller, J. Radioanal. Chem., 1977, 37. 637.

202


18

Table 1 Concentrations of elements in air at remote locations and in urban areas (ng kg-I air)* Element

Collafirth, Jundrau , Shetland Is., UK. Central Europe. Maritime Inland background * l o background * I 5 42 A1 43 0.19 1 pm) concentrations of particles, both ‘large’ (d = 0.1-1 have been found in emissions from a paper mill, with evidence of particle coagulation occurring in the plume at 7 km distance.434

F.4319432

Emissions from Motor Vehicles.-Primary exhaust aerosols are produced within the size range 0.01-0.1 pm and photochemical reactions may lead to the formation of secondary aerosols in the submicrometre range.273*435 Although the Pb is added to motor fuel in organic form as tetraethyl- or tetramethyl-lead, the particulate emissions are composed of inorganic oxides, sulphates, halides, and carbonates. The eventual particle-size range of this aerosol is affected by coagulation with the urban aerosol, which may result in particles up to 5 pm diameter.436Aerosol sampled by the M4 motorway in London contained an opaque, discrete rounded fraction (d < 0.1 pm), diaphanous chain aggregates (d = 0.1-1 pm), and larger dense flaky or amorphous particles (d = 0.5-5 pm) mainly of carbonaceous origin.436 Quantitative aspects of the release of Pb from motor vehicles are reviewed: it is estimated that for a traffic flow of 100 vehicles h-l, the output of Pb is 10 mg s-’ km-l (assuming 0.49 g Pb 1-’ in petrol and 0.24 1 consumption, with 75% emission).436About 6-10% of Pb emitted is generally deposited within 100-1 50 m from the m o t o r ~ a y . ~ ~In’ ,the ~ ~aged * (48 h) exhaust aerosol, (NH,),SO, - PbSO, has been identified as a major constituent, with PbSO, and PbBrCl present as minor components.439Photochemical and other factors that influence the formation of Pb compounds from vehicle exhaust are discussed ~ e p a r a t e l y . ~ The ~ ~ ratios , ~ ~ ~ of Br :Pb in exhaust emissions are closely related to the fuel formulation, so that in Perth, W. Australia, ratios of 0.61 and 0.59 are found in motor spirit and in air particulate, respectively, while in the US lower ratios of 0.39 and 0.29 have been

C. J. Muskett, L. H. Roberts, and B. J . Page, Sci. Total Environ., 1979, 11, 73. L. K. Thompson, S. S. Sidhu, and B. A. Roberts, Environ. Pollut., 1979. 18. 221. 4 3 2 R. C. Severson and L. P. Gough, J . Environ. Qual., 1976, 5, 476. 4 3 3 F. G. Taylor, jun., L. K. Mann, R. C. Dahlman, and F. L. Miller, in ‘Cooling Tower Environment 1974’, USERDA Conf. 740302. NTIS, Springfield. VA, 1975. p. 408. 4 3 4 E. E. Hindman 11, P. V. Hobbs. and L. F. Radke, J . Air Pollut. Control Assoc., 1977, 27,224. 4 3 5 D. F. Miller, A. Levy, D. Y. H. Pui, K. T. Whitby, and W. E. Wilson, jun., J . Air Pollut. Control Assoc., 1976, 26, 576. 43h A. C. Chamberlain, M. J. Heard, P. Little, and R. D. Wiffen, Philos. 7rans. R . SOC.London, Ser. A , 1979,290,577, 4 3 7 J . J. Huntzicker, S. K. Friedlander, and C. I. Davidson, Environ. Sci. Technol.. 1975, 9, 448. P. Little and R. D. Wiffen, Armos. Environ., 1978, 12, 1331. 43y P. D. E. Biggins and R. M. Harrison, Nature (London),1978, 272, 53 I . 44u R. M. Harrison and R. Perry, Atmos. Environ., 19’18, 12, 957. 4 4 1 P. D. E. Biggins and R. M. Harrison, Enilirotz. Sci. Techno/., 1979, 13, 558. 442 B. H. O’Connor. G. C. Kerrigan. W. W. Thomas. and A. T. Pearce, Atmos. Enriron., 1977. 11, 635. 43u 431

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An alternative to the use of Pb-halide compounds in motor fuel as ‘anti-knock’ additives is ‘MMT’ (methylcyclopentadienyl-Mn tricarbonyl), which results in exhaust emissions of Mn 304.443 Typical emission rates from vehicles powered with petroleum spirit were 0.08 mg Mn km-I in 1977, or -15% of the Mn added to the Exhaust from a light-duty diesel engine released -0.15 g particulates km-I at 60 km h-I, consisting of 60-75 wt% organic compounds and iron.Sci. Technol., 1975, 9, 15 1. 560 P. Little and R. D. Wiffen, Atmos. Enciron., 1977, I I , 437. P. A. Cawse, AERE Harwell Rep. R9886, H.M.S.O., London. 1981. s62 J. A. Garland, Atmos. Enuiron.. 1978, 12, 349.

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Figure 4 Enrichment factors and dry deposition velocities of elements in air particulate at Styrrup, Notts., 1919 (Reproduced by permission from AERE Harwell Report R 9886)

The net daily particle exchange between the atmosphere and natural surfaces has been studied using fast response sensors to record vertical wind speed and particle c ~ n c e n t r a t i o n .At ~ ~ ~night, upward particle fluxes were found from grass, pine forest, and maize, but downward fluxes occurred in part of the day: over snow and wet soil the fluxes were upward at all times.564Dry deposition of particulate Pb to tree leaves in an urban area was measured from the difference in the ratio 210Pb/Pb in air (0.13 d.p.m.* lug-') and Pb of soil origin (0.04 d.p.m. From wind-tunnel tests with 203Pb-labelledexhaust it was found that compared with bare soil, the Vg to grass-covered soil (of non-aggregated aerosol) was increased by 4-fold to 0.14 cm s - ' . ~ ~ O Similar tests are described on the deposition of 212Pb-taggedaerosols to barley, filter paper (ideal smooth surface), and simulated grass.566 Relative contributions of sedimentation, inertial impaction, and eddy diffusion to dry deposition of Cd, Pb, and Zn to Avenafatua indicated impaction as the main mechanism.567The Vgfor particulate Cd, Pb, and Zn to grass agreed well with values derived from micrometeorological methods and indicated deposition

* d.p.m. = disintegrations per minute. M. L. Wesely, B. B. Hicks, W. P. Dannevik. S. Frisella, and R. B. Husar, A m o s . Envirotz., 1977, 11, 561. 564 M. L. Wesely and B. B. Hicks, in 'Proc. 4th Symp. Turbulence, Diffusion and Air Pollution, Reno 1978', Am. Met. SOC.,Boston, 1979, p. 5 10. 565 J. Servant, in USERDA Symp. Ser. No. 38. NTIS. Springfield, VA. 1976. p. 87. 566 A. Ahmed, J. Porstendorfer, and G. Robig. in ref. 41. p. 279. 567 C. 1. Davidson and S. K . Friedlander. J . Geophys. Res.. 1978, 83, 2343.

563

52


rates of Cd, 2; Pb, 95; and Zn, 160 kg km-' yr-' in the Rhine-Ruhr area:568 however, the V g for Cd and Pb decreased with increasing concentrations of these elements in air and may indicate a saturation mechanism.568For SO,, a V gof 0.9 cm s-' to mixed forest exceeded a V gof -0.1 cm s-' for particulate The multielement composition of dry deposition collected in non-urban regions of the UK has been reported together with data on dry-deposition velocities of elements obtained by simultaneous measurement of air concentrations.222 Deposit gauges show that in urban regions the undissolved deposit is frequently from 200-600 mg m-, day-' or an order of magnitude more than in rural areas of the UK.570In New York City, the average dustfall of metals is Cd 0.0067, Cu 0.033, Fe 5.7. Ni 0.13, Pb 0.83, V 0.17, and Zn 0.83 mg m-' Removal by dry deposition of emissions from a coal-fired power station is estimated as -10% for particles with V g = 1 cm s-I, deposited in a 22.5" sector within 50 km, but -25% for larger particles with Vg= 3 cm

Precipitation Scavenging.-A detailed summary of both theoretical and field studies on in-cloud ('rainout') and below-cloud ('washout') scavenging of aerosols by rain and snow was presented at the 1974 Illinois Conference.573Measured washout factors for some 20 elements, defined as ratio of concentration in surface level precipitation average concentration in surface level air

9

are listed,574and the tendency for these factors to increase with particle size is discussed by gat^.^^^ Washout ratios of 300-1000 are expected for SO:- aerosols in situations not influenced by large SO:- inputs from s e a - s ~ r a y . ~The ~ , relative importance of direct SO:- scavenging by precipitation and removal following oxidation of SO, has been examined.576 Experimentally determined washout coefficients (fractional amount of pollutant aerosol removed per unit time by precipitation) of particles from 0.01-1 ,urn diameter ranged from 2 x to 1 x s-I, or at least an order of magnitude above estimates derived from theoretical considerations, and the influence of coagulation and condensation growth of particles on this difference is inferred.577A relatively large scavenging collection efficiency (SCE, or collision efficiency x retention efficiency) of precipitation is observed for particles from 0.0 1-0.05 pm diameter (SCE 0.8), and is attributed to an increasing hygroscopic component with D. H. Schwela, Ecotoxicol. Environ. Safety, 1'979, 3. 174. J. S. Eaton, G . E. Likens, and F. H. Bormann, Tellus. 1978. 30. 546. 570 'The Investigation of Air Pollution; Deposit Gauges', Rep. Warren Spring Laboratory, Dept. of Industry, London, 1978. 5 7 1 M. T. Kleinman. T. J . Kneip, D. M . Bernstein. and M. Eisenbud. in USERDA Symp. Ser. No. 42.. NTIS, Springfield, VA. 1977, p. 144. s 7 2 L. E. Wangen, in Rep. LA 8023-PR, LASL Health Division, 1979, p. 159. 5 7 3 'Precipitation Scavenging (1974)', USERDA Symp. Ser. No. 41.. NTIS, Springfield, VA, 1977. 574 W. G. N. Slinn, L. Hasse, B. B. Hicks, A. W. Hogan, D. Lal. P. S. Liss, K. 0. Munnich. G . A. Sehmel, and 0. Vittori, Atmos. Eni,iron., 1978. 12, 2055. 575 D. F. Gatz. Water Air Soil Pollut., 1975, 5 , 239. 5 7 6 J. M. Hales, Armos. Eniiiron., 1978, 12, 389. 5 7 7 H. M. Davenport and L. K. Peters, Atrnos. Enuiron., 1978, 12, 997. 568

569


53

decreasing size in this range.578With particles from 1-4 pm diameter, SCE again increases with size, removal being mainly by inertial impaction with Models have been developed to compute the effects of humidity and electric charge on precipitation scavenging. 580 A high collection efficiency for below-cloud scavenging of aerosols by snow crystals has been confirmed by direct observation of attached particles from the ambient atmosphere, mainly from 0.5-1.5 pm diameter.581The primary capture mechanism by snow appears to be simple interception.582In large hailstones from an arid region, concentrations of large particles (d = 40-60 pm) were typically 104- lo6 kg-I of ice.583In snow samples from Antarctica, 60% of the crystal nuclei contained clay minerals such as illite and kaolinite and 20% contained NaC1.584 Analysis of snow has been used to indicate current industrial p o l l ~ t i o n , ~and ~~-~~~ alkaline snowfalls have occurred by scavenging of Ca and Mg carbonates in dust emissions from cement industries.589Snow profiles from Antarctica, deposited from 1914-1974, have revealed comparable concentrations of Ag, Cd, Cu, Pb, and Zn at all depths, possibly from a natural origin such as volcanic or maritime-derived a e r o s 0 1 s . ~A ~ ~similar , ~ ~ ~ feature in pre-1900 ice cores from Greenland has provided analytical data that suggests an input by aerosol deposition following crustal outgassing and volcanic activity rather than continental dust or maritime 593

Total (Wet + Dry) Deposition.-The input of elements from the atmosphere to the ground by wet and dry deposition is of particular interest to agriculturalists and ecologists to establish nutritional or toxic effects and cycling of elements in terrestrial and aquatic environments. The accumulation of such deposition in soil has indicated the extent of industrial pollution. From analysis of rainwater and dry deposition, the total deposition of 40 elements was recorded each month at rural locations in the UK from 19721975.72The solubility of elements in this deposition was high for As, Cu, Ni, Pb, Se, and Zn, but lower for elements mainly associated with larger particles, namely Al, Eu, Fe, Sc, Sm, and Ti, which would be less available to biological Analysis of the soluble fraction was made from 1967-1972 at rural sites in

L. F. Radke, M. W. Eltgroth, and P. V. Hobbs, in ‘Proc. Am. Met. SOC.Conf. Cloud Physics and Atrnos. Electricity’, Washington, 1978, p. 44. 579 S. N. Grover, H. R. Pruppacher, and A. E. Hamielec, J . Atmos. Sci., 1977, 34, 1655. 5 8 0 P. K. Wang, S. N. Grover, and H. R. Pruppacher,J. Atmos. Sci., 1978, 35, 1735. 5 8 ’ C. Magono, T. Endoh, F. Veno, S. Kubota, and M. Itasaka, Tellus, 1979, 31, 102. 5 n 2 E. 0. Knutson, S. K. Sood, and J. D. Stockham, Atmos. Enuiron., 1976, 10, 395. 583 J. Rosinski, K. A. Browning, G. Langer, and C. T. Nagamoto, J . Atmos. Sci., 1976, 33, 530. *84 M. Kurnai, J . A m o s . Sci., 1976, 33, 833. 5 8 5 E. J. Forland and Y. T. Gjessing, Atmos. Environ., 1975,9, 339. m A. W. Struempler, Atmos. Environ., 1976, 10, 33. 5n7 P. J. Galvin and J. A. Cline, Atmos. Enuiron., 1978, 12, 1163. W. G . Franzin, G. A. McFarlane, and A. Lutz, Environ. Sci. Technol., 1979, 13, 15 13. 589 R. J . Allan and I. R. Jonasson, A m o s . Enuiron., 1978, 12, 1169. C. Boutron and C . Lorius, Nature (London), 1979,277,55 1. s 9 1 C. Boutron, Nature (London), 1980, 284, 575. 59*M. M. Herron, C . C. Langway, jun., H. V. Weiss, and J . H. Cragin, Geochim. Cosmochim Acta., I977,41, 9 15. 593 H. V. Weiss, M. M. Herron and C. C. Langway, jun., Nature (London), 1978, 274, 353.

57n

54


England where weights of insoluble deposit ranged from 20-250 kg ha-' yr-I, being directly related to proximity of industry.5y4 In the Nigerian savanna, total deposition of Br, Ca, Co, Cu, Fe, Ni, Sc, Sm, Th, V, Zn, NH;, NO;, and SO:- showed an order of magnitude increase in the rainy season (April to October) compared with the dry season.s95It was noted that enrichment factors (normalized to Sc in average soil) for As, Ni, Pb, Sb, Se, and V in this deposition in Nigeria were generally an order of magnitude below those recorded at Chilton, Oxfordshire U K , reflecting industrial influences at high latitudes in the N. hemisphere.595In Trinidad, major anions and cations essential to plants have been measured in rainfall and deposited Analysis of rainwater samples from Norway has shown similar regional deposition patterns for As, Cd, Pb, Sb, Se, and V, which is mainly attributed to the transport of aerosols from industrial regions of Europe, although for Se a contribution from maritime-derived aerosols is indicated.s97A comparison of rural and urban deposition rates of some metals reported in the literature is made in Table 5. Much attention has been given to the acidity of precipitation and deposition of SO:-, particularly in Canada and Scandinavia, to investigate the disturbance of soil, forest, and aquatic ecosystems.600-604In Ontario, episodes of acid precipitation gave pH 3.0 in rainwater605 and acidification of a lake was related to scavenging of H,SO, aerosols, probably derived from local smelting industry.606 In Norway, deposition of non-maritime SO:- is heaviest in the south (4 g SO:- rn-, yr-') and precipitation has an average pH of 4.3; about 75% of the SO:- is deposited as wet d e p o ~ i t i o n . ~In~ ' the rural E. Midlands of the UK it is reported that rainwater acidity decreases from west to east, away from major combustion sources of SO,.6o8 In W. Germany, deposition of S from the atmosphere to spruce forest (80-86 kg ha-' yr-') exceeded accumulations in beech woodland (47-51 kg ha-' yr-') and on bare soil (23 kg ha-' ~ r - ' ) ,indicating ~ ~ ~ more efficient interception of aerosols by the canopy.609 Measurement of the true contribution of rainwater to total (dry + wet) deposition was made over one year at a rural site in S. England (Chilton, O ~ f o r d s h i r e ) .The ~~ rain collection funnel was covered during dry weather by an automatically operated screen so that this rainwater sample could be compared with a permanently exposed collector: over 76% of the total deposition of Co, Cu, Pb, Se, and Zn was G . A. Wadsworth and J . Webber, in ref. 72. p. 47. F. Beavington and P. A. Cawse. Sci. Total En~iron..1979. 13. 263. s96 R. C. Dalal, Water Resources Res.. 1979. 15, 1217. "' A. Semb, Res. Rep. F R 13/78, SNSF Project. Aas. Norway. 1978. P. A. Cawse, A E R E Harwell Rep. G1343, Didcot, Oxon.. 1980. 599 J . Ruppert, Waier Air Soil Pollui.. 1975. 4. 447. 6oo E. Gorham, Water Air Soil Pollut.. 1976, 6. 457. '"C. L. Schofield, Ambio, 1976, 5, 228. 602 W. W. McFee, J. M.Kelly. and R. H. Beck. Water Air Soil Pollui.. 1977, 7,401. '03 J . 0. Reuss. Water Air Soil Pollut., 1977, 7. 46 1. 6"4 'Proc. N A T O Conf. Effects Acid Precipitation on Terrestrial Ecosystems', ed. T. C. Hutchinson and M. Havas, Plenum Press, New York, 1980. '"'P. J Dillon, D. S. Jeffries, W. Snyder, R. Reid, N. D. Yan. D. Evans, J. Moss, and W . A. Scheider. J . Fisheries Hes. Bd. Canada, 1978, 35, 809. 'Ob R. J . Beamish and J . C . Van Loon, J . Fisheries Res. Bd. Canada, 1977. 34, 649. '"'F. H. Braekke, Res. Rep. FR6/76, SNSF Project, Aas, Norway, 1976. 60R A. Martin and F. R. Barber, A tmos. Enriron.. 19 78. 12. I48 1. 6oy R. Mayer and B. Ulrich, Atmos. Enuiron., 1978, 12, 375.

594

s93

'''

1.5

0.02 0.14 9.5 0.82 -

502

x 0.1 = kg hectare-'.

1.2 28 2.8 0.6 1 4.9 643

(0.5

Chilton, Oxon., Background station, UK12 Denmark 3 5

* ,pg cm-'

Rainfall, mm yr-'

Zn

v

Fe Pb

cu

Cd

Element

Rural

3.7 -

-

Membach, A rdennes, Belgium343 0.0 15 84 1.8 85% of Al, Sc, and Fe and 15% of Ca, Mn, and V.72 The Air-Sea Interface.-The downward flux and mechanisms by which atmospheric particles are deposited to the ocean are difficult to establish, being complicated by sea-air transfer processes that cause particulate matter to be ejected in bubble bursting and as spray formed during intense ocean turbulence. Many particulate metals (Al, Cd, Cr, Cu, Fe, Mn, Pb, and V) are known to be enriched in the sea surface microlayer compared to bulk seawater, either from transport to the surface by bubble flotation or by deposition of atmospheric trace elements.371Where atmospheric input fluxes are sought, the re-cycling of sea-salt particles and associated metals may distort the true net flux from air to sea. Recommendations are made for modelling the transfer of metals to oceans by wet and dry deposition,610and development of a multilayer model to describe transfer of air particulates past the air-sea interface is reviewed.574Dry deposition of particles to ocean surface films can be followed using radionuclides from nuclear weapon fallout as tracers, but complexities in mass-transfer rates arise from the presence of monolayer or multilayer films (organic and/or inorganic) and variable wind speeds that affect the shear of such films.611 The flux of metals from the atmosphere to the N. Atlantic Ocean has been estimated.610Atmospheric inputs to the North Sea of Cu and Pb were estimated as nearly 3 times the amounts discharged through the River Rhine, while for Mn, Ni, and Zn the relative inputs were almost The transport of Pb to the oceans and its subsequent fate has been examined:613industrial inputs of Pb to the world oceans are estimated as 4 x lo4tons yr-’ from the atmosphere and some 6 x lo4 tons yr-l by rivers and sewers, or about 40 times greater than the ‘neolithic rate’ of The flux of V from air to sea between latitudes 30°-600N is -2 x lo6 kg yr-l, or about 10% of the anthropogenic emissions from continental regions.614 In oceanic regions remote from industry such as the Gulf of Alaska, the input of Fe from the atmosphere is apparently an important source of Fe that is available to marine organism^.^'^.^^^ Interest in atmospheric inputs of elements to the Great Lakes system with respect to nutrient budget, acidity, and accumulation of heavy m e t a W 7 has led to specific modelling estimates of the dry deposition, allowing for local meteorological features,61Eand an appraisal of experimental appro ache^.^'^ Gatz 5 7 5 estimated that element inputs to Lake Michigan from wet and dry deposition are approximately ‘The Tropospheric Transport of Pollutants and other Substances to the Oceans’, US Natl. Acad. Sci./Natl. Res. Council, Washington DC, 1978. 6 1 1 G. A. Sehmel, in Rep. Batelle Pacific N.W. Labs., BNWL-SA-5597, Richland, WA, 1975, p. 1. 612 R. S. Carnbray, D. F. Jefferies, and G. Topping, Mar. Sci. Commun., 1979, 5, 175. 6 1 3 C. Patterson, D. Settle, B. Schaule, and M . Burnett, in ref. 373, p. 23. 6 1 4 R. A. Duce and G. L. Hoffman, Afmos. Enuiron., 1976, 10,989. 6 1 s W. C. Weimer and J . C . Langford, Armos. Environ., 1978, 12, 1201. 6 1 6 W. C. Weimer, J . C. Langford, and C. E. Jenkins, Rep. Batelle Pacific N.W. Labs., PNL-2280, UC 1 I , Richland, WA, 1978. 617 F. C. Elder, R. A. Fleming, and P. J Denison, in ‘Proc. 2nd Conf. Am. Met. SOC. on Hydrometeorology’, Toronto, 1977, p. 156. 6 1 8 H. Sievering, in ref. 564, p. 5 18. 61y J. W. Winchester, J . Great Lakes Res., 1976, Vol. 2 , Suppl. 1. 610


57

equal; for Fe and Pb the atmospheric inputs are about double the soluble inputs of these elements by streams. In the southern basin of Lake Michigan, surface enrichment of Cd, Cu, Pb, and Zn occurred mainly in the particulate phase being mainly associated with fly ash, other particles of anthropogenic origin and diatom fragments.620In fact, a flux of 106--107 fly ash particles cm-2 yr-’ is estimated.621 With respect to phosphorus it is reported that 18% of the total P budget of Lake Michigan is probably contributed by atmospheric deposition.622The deposition flux to Lake Huron averaged 1.4 ,ug P cm-2 day-’, with 29% of the P on particles (0.5 pm diameter.623 The dry and wet deposition of available P (i.e. water and acid-soluble P) was approximately equal and comprised 44% of total P in the 7 Effects of Airborne and Deposited Particulates

The effects of air particulates may be considered by reference to targets;625damage to the target or receptor organism may be acute (short exposures to high concentrations of pollutants) or chronic (exposures to lower concentrations over longer periods). Effects on biological targets may be expressed directly by physical or chemical mechanisms, or indirectly by alteration of the habitat.625The possibility of synergistic action by pollutants must also be considered.625Effects on human health, animals, plants, and weather have been reviewed.626

Hazard to Man.-Inorganic particulates that are inhaled into the respiratory tract are deposited mainly by impaction, sedimentation, interception, and d i f f ~ s i o n . ~ ~ ~ - ~ ~ The coarser fraction of the inhaled particles (d > 5 pm) are deposited in the nasal passages, nasopharynx, oral passages, and larynx. The next main region of deposition is the tracheobronchial zone and finally, for inhaled particles with aerodynamic diameters from 0.1-2 pm, deposition occurs mainly in the alveolar region of the lung beyond the terminal bronchioles. For subjects breathing particles of 0.1-4 pm diameter via the nose, alveolar deposition is -20%.627The density, shape and solubility as well as size of inhaled particles is of primary importance in deposition, retention, and clearance from the respiratory tract: tissue and cellular reactions to the particulates, including problems of asbestosis and silicosis are

A. W. Elzerman, D. E. Armstrong, and A. W. Andren, Entiiron. Sci. Technol., 1979, 13, 720. J. J. Alberts, J. Burger, S. Kalhorn, C. Seils, and T. Tisue, in ref. 148, p. 379. 622 T. J. Murphy and P. V. Doskey, Rep. EPA-600/3-005, US Environ. Protection Agency, Duluth, MN, 620

621

1975. R. Delumyea and R. L. Petel, Atmos. Enuiron., 1979, 13, 287. 624 R. Delumyea and R. L. Petel, Water Air Soil Pollur., 1978, 10, 187. 6 2 5 M. W. Holdgate, Philos. Trans. R. Soc. London, Ser. A , 1979, 290, 59 I . 626 ‘Air Pollution’, Vol. 2, 3rd Edn., ‘The Effects of Air Pollution‘, ed. A. C. Stern, Academic Press, New York, 1977. M. Lippmann and B. Altshuler, in ‘Proc. 20th Ann. O H O L O Biol. Conf. Air Pollut. Lung’, ed. E F. Aharonson and A. Ben-David, Wiley, New York, 1975, p. 25. R. Hounam and A. Morgan, in ‘Lung Biology in Health and Disease’, Vol. 5, ‘Respiratory Defence Mechanisms’, Part I , ed. J . D. Brain, D. F. Proctor, and L. M. Reid, Marcel Dekker, New York, 1 9 7 7 , ~ 125. . 62y M. Lippmann, in Handbook of Physiology, Section 9. ed. H. L. Falk, Williams and Wilkins, Baltimore, 1977, Ch. 14, p. 213.

623

58


recently r e v i e ~ e d . ~ ~Inhalation O - ~ ~ ~ of metallic aerosols may damage arterial, renal, and nervous ~ y ~ t e m ~ . ~ ~ ~ - ~ ~ ~ The haemolytic properties of elements in particulate form followed the order Si > Ni > Co > Cr > Fe > Mo > Ti > Cd > Zn and an initial direct interaction between the red cell membrane and particle surface was indicated, with the additional possibility of toxicity from dissolved At the cellular level, excessive concentrations of heavy metals can inhibit or inactivate enzyme systems.637 Table 6 Research on toxicity of dusts to man and animals Type of dust or major element contained A1 (+Zr) Be Cd co F Fe Mn Ni NO3 Pb

Si

Ta Zn Asbestos dusts including amphiboles and serpentine (chrysotile) forms

A uthorslR eferences Styles and Wilson63x Zorn et al.639 Asvadi and Hayes;64nBus et Oberg;h42 G e ~ r g i a d iPopov ; ~ ~ ~ et ~ 1 . ' ~ ~ Kinkead et ~ 1 . ' ~ ~ Nettesheim et al.647 Bergstrom and R ~ l a n d e rCoulston ; ~ ~ ~ and Griffin;649 Singh et al.650 Camner et Bell and Hackney652 Bouley et al.;653Griffin el al.;654Hapke and Abe1;655 Morgan and H o l m e ~ Schultz ; ~ ~ ~ and Skerfving'jS7 Adamis and ti ma^-;^^' Le Bouffant et al.;"' Keusch and Ruettner;66nSingh et a1.66' Bell et Bruch et al.;663Sackner et al.;664 Schlesinger et aL6'j5 Nemetschek-Gander et a1.666 Rosenberger and GruendeP7 Leong et a1.;668Morgan et al.;h699670 Rahman et al.;671 Singh et a1.;6'2 Wagner;"7' Wehner el al."'

J. S. Harrington and A. C. Allison, in ref. 629, p. 263. 'Inhaled Particles Vol. 4', Part 2, ed. W. H. Walton and B. McGovern, Pergamon Press, Oxford, 1977. 632 'Airborne Particles', Natl. Res. Council USA, Univ. Park Press, Baltimore, 1979. 633 'Environmental Hazards of Metals'. I.T. Brakhnova, Consultants Bur., New York, 1976. '"J. Calop, P. lsoard, and R. Fontanges, Bull. Med. Leg. Urgence Med.. Cenf. Anti-Poisons. 1977, 20, 404. ""Handbook on the Toxicology of Metals', ed. L. Friberg, G . F. Nordberg, and V. B. Vouk, Elsevier/N. Holland Biomedical Press, Amsterdam, 1979. 636 T. Rae, J . Pafhol., 1978, 125, 8 I . 6 1 7 G. L. Eichorn, in 'Ecological Toxicology Research', ed. A. D. Mclntyre and C. F. Mills. Plenum Press, New York, 1976, p. 123. 63M J . A. Styles and J. Wilson,Ann. Occup. Hjjg., 1976, 19, 63. 639 H. Zorn, T. Stiefel, and H. Diem. Zenrralbl. Arbeitsmed. Arbeitsschutz Proph.d., 1977, 27. 83. 640 S. Asvadi and J. A. Hayes, A m . J . Pathol., 1978. 90. 89. 64 I J. S. Bus, A. Vinegar, and S. M. Brooks, A m . Reu. Respir. Dis.. 1978, 118. 513. b42 S. G. Oberg, Diss. Abstr. In(. B . , 1977, 37, 4030. 64' R. M. Winston, Br. Med. J.. 1975, May 15, 401. 644 G. A. Georgiadi, Zh. Ushn. Nos. Gorl. Bolezn., 1978, No. 1.63. L. N. Popov. T. A. Kochetkova. M. I. Gusev, N. A. Markina, E. V. Flfimova. and M. A. Timonov. Gig. Sanit., 1977, No. 6 , 12. b4b E. R. Kinkead, K. 1. Darmer, jun.. L. C. DiPasquale, and C. C. Haun. Rep. AMRL-TR, Aerospace Med. Res. Lab., Univ. California, Irvine, 1975. 6 4 7 P. Nettesheim. D. A. Creasia. and T. J . Mitchell, J . N a f l . Cancer Inst.. 1975. 55. 159. 63"


59

Examples of recent research into biochemical and toxicological properties to man and animals of inhaled dusts are listed in Table 6. Cytotoxicity of inhaled Pb aerosols towards alveolar macrophages, which provide defence against respiratory infection, has been d e m ~ n s t r a t e d . Other ~ ~ ~ , ~workers ~~ have applied methanol extracts of air particulates from urban areas to test bacteria, to show mutagenic activity from organic pollutants associated with inorganic The high incidence of respiratory disease in many industrial areas of the UK especially prior to control legislation in 1960 is confirmed by data from other polluted cities of the world;680however, recent improvements in health cannot yet be attributed to a lower concentration of any specific pollutant.680 The ‘Environmental Health Criteria Programme’ organized by the W.H.O. in 1973 was designed to study the relationship between exposure to pollutants and health and to identify new or potential pollutants. A series of reports are now available that discuss Hg,544Pb,681 and sulphur oxide^.^ Health effects of R. Bergstrom and R. Rylander, in ref. 152, p. 178. F. Coulston and T. Griffin, Rep. PB-268643, NTIS, Springfield, VA, 1977. ‘”J. Singh, J. L. Kaw, and S. H. Zaidi, Toxicology, 1977,8, 177. 651 P. Camner, A. Johansson, and M. Lundborg, Enuiron. Res., 1978, 16,226. 6J2 K. A. Bell and J. D. Hackney, Rep. PB-257745, NTIS, Springfield, VA, 1976. 653 G. Bouley, A. Dubreuil, F. Arsac, and C. Boudene, in ref. 4 1, p. 127. 654 T. B. Griffin, F. Coulston, H. Wills, and J. C . Russell, Environ. Qual. S a j Suppl., 1975, 2, 202. 655 H. J. Hapke and J. Abel, Dtsch. Tieraerztl. Wochenschr., 1978, 35, 288. ‘S6 A. Morgan and A. Holmes, Enuiron. Res., 1978, 15,44. 657 A. Schutz and S. Skerfving, Scand. J . Work, Environ. Health, 1976, 2, 176. 658 Z. Adamis and M. Timar, Br. J. Exp. Pathol., 1978, 59,411. 6 5 9 Le Bouffant, H. Daniel, J . C. Martin, and S. Bruyere, C. R . Hebd. Seances Acad. Sci., Ser. D , 1977, 285,599. 66u F. Keusch and J. R. Ruettner, Exp. Cell Biol., 1978, 46, 257. J. Singh, P. N. Viswanathan and S. H. Zaidi, in ‘Proc. 1st Int. Symp. Environ. Pollut. Human Health, 1977, p. 3 14. K . A. Bell, W. S. Linn, and J . D. Hackney, Rep. PB-275789, NTIS, Springfield, VA, 1978. 663 J. Bruch, G . H. M. Krause, and H. D. Rogge, VDI Bericht. 1978, 314, 159. 664M. A. Sackner, D. Ford, R. Fernandez, J. Cipley, D. Perez, M. Kwoka, M. Reinhart, E. D. Michaelson, R. Schreck, and A. Wanner, Am. Rev. Respir. Dis., 1978, 118,497. h65 R. B. Schlesinger, M. Lippmann, and R. E. Albert, J . Am. Ind. Hyg. Assoc., 1978, 39, 275. 666 H. Nemetschek-Gansler, Th. Nemetschek, H. Polley, H. Wesch, H. D. Renovanz, and H. Franz, Pneumonologie, 1975, 152, 299. G. Rosenberger and H. D. Gruender, in ‘Proc. 20th World Vet. Congr., Vol. 3’. 1975, 2059. 668 B. K. J. Leong, R. J. Kociba, H. C. Pernell, R. W. Lisowe, and L. W. Rampy, J. Toxicol. Environ. Health., 1978, 4,645. 669 A. Morgan, P. Davies, J. C. Wagner, G. Berry, and A. Holmes. Br. J . Exp. Pathol., 1977, 58,465. 670 A. Morgan, A. Holmes, and R. J. Talbot, Ann. Occup. Hyg., 1977, 20. 39. 6 7 1 Q. Rahman, M. U. Beg, P. N. Viswanathan, and S. H. Zaidi, Scand. J . Work, Enuiron. Health, 1975, 1, 50. 6 7 2 J . Singh, M. U. Beg, J. L. Kaw, P. N. Viswanathan, and S. H. Zaidi, Acra Pharmacol. Toxicol., 1976, 39,77. h73 J . C. Wagner, Ann. Anaf. Pathol., 1976, 21, 21 1. 674 A. P. Wehner, G. E. Dagle, W. C. Cannon, and R. L. Buschbom, Environ. Res., 1978, 17,367. 675 H. W. Schlipkoter, G. H. M. Krause, R. Stiller-Winkler, and A. Brockhaus, Zhl. Bakt. Hyg. I Aht. Orig., 1977, B165, 251. 676 C. Aranyi, F. J. Miller, S. Andres. R. Ehrlich, J. Fenters, D. E. Gardner, and M. D. Waters, Environ. Res., 1979, 20, 14. 6 7 7 H. Tokiwa, K. Morita, H. Takeyoshi, K . Takahashi, and Y. Ohnishi, Mutation Res., 1977. 48, 237. 67x W. Dehnen, N. Pitz, and R. Tomingas, Cancer Letf., 1977,4, 5 . 679 R. Talcot and E. Wei, J. Natl. Cancer Inst.. 1977, 58,449. J. McK. Ellison and R. E. Waller, Enuiron. Res., 1978, 16, 302. ‘Environmental Health Criteria No. 3, Lead’. W.H.O. Geneva, 1977. m2 ‘Environmental Health Criteria No. 5 , Nitrates’, W.H.O. Geneva, 1977. 648 649

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60


As, Cd, Cr, Hg, Ni, and Pb in air, food, and water were reviewed at an E.E.C. Symposium,683and in a special report on Cd684it is estimated that 13--19% of inhaled Cd is absorbed by adults. The inhalation risks from Cd, Hg, and Pb are also examined in a consensus report of specialists.685Separate reviews of environmental hazards are available for Ag,686Be,687Cd,688Cr,689In,690and Tl.691Potential hazards to health of man, animals, and plants by trace-metal emissions from combustion of coal have been discussed by several a ~ t h o r s . ~ ~ ~ - ~ ~ ’ Particulate Pb in the atmosphere may enter man by direct inhalation or following contamination of Inhalation by adults of air containing 1 pg Pb m-3 can lead to accumulation of 1.2 pg Pb/100 ml of blood,697while oral intake of 100 ,ug Pb would contribute -6-18 pg Pb/100 m1;68’ normal diets give an intake of 200-300 pg Pb day-1.681A recent review has been made of factors affecting the deposition of Pb aerosols in the human lung, the blood Pb levels and eventual It is found that dusts from urban roads storage in the body, mainly in bone may contain up to 3600 pg Pb g-’ and 10 pg Cd g-’ and represent a potential health hazard to children in particular.699Much research into the uptake an& metabolism of Pb by man and animals has been made using specific Pb isotope ratios as marker^."^*^^^ In one such experiment a decrease in ratios of natural 206Pb/204Pb and 206Pb/207Pb in blood of adults in winter was attributed to a release of skeletal Pb deposits that are of different geological age, having lower isotope ratios than Pb in current air and diet.’O1 The carcinogenic and fibrogenic effects of fibrous dusts originating from asbestos, building, and textile (glass fibre) industries have been demonstrated in animal and Pott 703 advocates inclusion of other inhalable fibres in ‘Trace Metals, Exposure and Effects’, C E C Rep. EUR6389, E.E.C. Luxembourg, 1979. ‘Criteria (Dose/Effect Relationships) for Cadmium’, C E C Rep. EUR5697, E.E.C. Luxembourg, 1978. ‘Effects and Dose-Response Relationships for Toxic Metals’, ed. G . F. Nordberg, Elsevier, Amsterdam, 1976. ‘Trace Metals in the Environment, Vol. 2, Silver’, I. C . Smith and B. L. Carson, Ann Arbor Press, MI, 1977. 6 R 7 Rep. Oak Ridge Natl. Lab., ORNL-EIS Pt. 6, Beryllium, USEPA, 1978. Rep. Oak Ridge Natl. Lab., ORNL-EIS Pt. 4, Cadmium, USEPA, 1978. ‘Kg Rep. Oak Ridge Natl. Lab., ORNL-EIS Pt. 3, Chromium, USEPA, 1978. 690 ‘Trace Metals in the Environment Vol. 5 , Indium’, 1. C . Smith and B. L. Carson, Ann Arbor Press, MI, 1978. 6 9 ’ ‘Trace Metals in the Environment, Vol. 1, Thallium’, I. C. Smith and B. L. Carson, Ann Arbor Press, MI, 1977. D. L. Davidson and E. M. Cause, in ‘Proc. Ann. Conf. Microbeam Anal. Soc.’, 1978, 13, Paper 59a. 693 E. Piperno, in ref. 400, p. 192. 694‘Effects of Trace Contaminants from Coal Combustion’, ed. R. I. Van Hook and W. D. Shults, USERDA Rep. 77-64, NTIS, Springfield, VA, 1977. 69s A. Robson, Rep. PL-GS/E/5/79, CEGB, London, 1979. 696 ‘Lead and Health’, Rep. D.H.S.S. Working Party on Lead in the Environment, H.M.S.O., London, 1980. 697 A. C . Chamberlain, W. S. Clough, M. J . Heard, D. Newton, A. N. B. Stott, and A. C. Wells, Proc. R . SOC.London, Ser. B., 1975, 192. 77. A. C. Chamberlain, M. J. Heard, P. Little, D. Newton, A. C. Wells, and R. D. Wiffen, A E R E Harwell Rep. R9198,H.M.S.O., London. 1978. R. M. Harrison, Sci.Total Enciron.. 1979, 11, 89. R. B. Holtzrnan, in ref. 539, p. 37. W. 1. Manton, Arch. Environ. Hlth., 1977, 32, 149. ’ 0 2 H. W. Schlipkoter and K. H. Friedrichs, Klima Kaelte Ing.. 1975, 3, 359. ’03 F. Pott, Staub. Reinhalt. Luji, 1978, 38,486. h83

b84

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””

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61

addition to asbestos when evaluating carcinogenic potency. Relationships between exposure to asbestos fibres and subsequent development of pulmonary disease are discussed in a recent v01ume.l~~ A bibliography of 1425 references is now available on asbestos in the environment, covering physico-chemical properties and biological In cities, 2000-6000 fibres m-3 are reported, increasing to 11 000 fibres mP3 near an asbestos factory.702In a survey of 49 US cities, chrysotile asbestos fibres were mainly in the range 1-5 ng mP3, but attained 30 ng mP3near industrial users. 705 The accumulation in soil of inorganic particulate pollutants deposited from the atmosphere has been used to examine the severity and dispersion of industrial p011ution,~~~-~~* and damage to amenity f o r e s t ~ ,711 ~ 'and ~ ~ crops. 175,708 Contamination of crops by direct deposition of metals from the atmosphere or by uptake of metals from polluted soil may be hazardous to man712,713 and grazing At 10 m from a motonvay, soil contained 1200 pg Pb g-l, but since only 10% of Pb emitted from exhausts is deposited locally, contamination of rural areas is expected;716such depositions are reported to contribute >90% of total Pb in grass in rural Denmark.717In a forest ecosystem, Cd, Cu, Pb, and Zn deposited in dusts from a lead smelter retarded the biological decomposition of litter and humus.71*

-

Air-quality Indices and Standards for Particulate Pollutants.-The abatement and control of air pollution by technical and legislative procedures is now an established part of urban and national planning, to achieve short- and long-term goals for levels of particulates in the a t m o ~ p h e r e .In ~ ~the~ UK * ~ ~a ~system of control by the 'Best Practicable Means' approach has evolved since the first Alkali Act in 1863; thus 'Presumptive Limits' are set by the Health and Safety Executive and may be varied 722 In the US, the to meet special operating conditions at individual '04

J. H. Tucker, P. M. Cook, G. L. Phipps, G. N. Stokes, and P. H. Lima, Rep. EPA/600/3-78/066, US Environ. Protection Agency, N. Carolina, 1978.

705 L. Bruckman and R. A. Rubino, J . Air Pollut. ControlAssoc., 1978, 28, 1221. lo6J. H. Horton, R. S . Dorsett and R. E. Cooper, Rep. DP1475, Savannah River Lab., Aiken, S. Carolina, 1977. '01 V. Masek, Staub. Reinhalt. Luft, 1978, 38,493. ' 0 8 'Trace Element Contamination of the Environment', D. Purves, Elsevier, Amsterdam, 1977. ' 0 9 L. Lerman and E. F. Darley, in 'Responses of Plants to Air Pollution', ed. J. B. Mudd and T. T. Kozlowski, Academic Press, New York, 1975, p. 141. 'lo D. Auclair, Ann. Sci. Forest., 1977, 34,47. 7 1 1 M. Swieboda, Acta SOC. Bot. Pol., 1976, 45, 17. 7 1 2 F. Beavington,Environ. Pollut., 1979, 9, 21 1. 7 1 3 R. Guderian, G. H. M. Krause, and H. Kaiser, Schriftenr. Landesanst. Immisionsschutz Landes Nordrhein- Westfalen, 1977, 40, 23. 714 C. R. Dorn, J. 0. Pierce, G . R. Chase, and P. E. Phillips, Environ. Res., 1975, 9, 159. 'I5 G. Rosenberger, H. D. Griinder, and G. Crossman, Dtsch. Tierartzl. Wochenschr., 1976, 83,478. 716 G. L. Wheeler and G. L. Rolfe, Environ. Pollut., 1979, 18, 265. 7 1 7 J. C. Tjell, M. F. Hovmand, and H. Mossbaek, Nature (London), 1979,280,425. D. R. Jackson and A. P. Watson, J . Environ. Qual., 1977,6, 33 1. 'I9'Manual on Air Quality Management', ed. M. J. Suess and S. R. Craxford, W.H.O. Reg. Publ. I, W.H.O., Copenhagen, 1976. 720 'The Pollution Control Policy of The European Communities', S. P. Johnson, Graham and Trotman, London, 1979. 7 2 1 F. E. Ireland and D. J. Bryce, Philos. Trans. R . SOC.London, Ser. A , 1979,290,625. 122 E. Briggs, in 'Eurochem. Conf. Chem. Engng. in Hostile World,' Birmingham, England, 1977, Paper 6-28- 1.

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Environmental Protection Agency (EPA) has set national ambient air-quality standards (NAAQS) to protect public health against pollution by Pb, sulphur oxides, and total suspended particulates, in addition to emission standards for specific source^.^^^-'^^ The assessment of health hazards in an adequate manner to set regulatory limits for pollutants is well recognized as a complex and onerous t a ~ k . ~However, ~ ~ - ~increases ~ ~ in deaths in urban populations during acute pollution episodes in London, the Meuse Valley, Osaka, New York, and Donora (Pennsylvania) and detailed epidemiological studies have led to the introduction of pollution indices to relate health and For total suspended particulates (TSP) the W.H.O. has put forward a tentative interim guideline of 60-90 pg m-3 as an annual mean beyond which effects of long-term exposure on health are p r ~ b a b l e ,For ~ short-term exposures, the 24 h guideline is 150-230 pg m-3.5 In the case of smoke, guidelines for exposure limits are 100-150 pg mP3(24 h mean) and 40-60 pg mP3 (annual arithmetic mean).5 The Greater London Council guideline for TSP is 40 ,ug m-3 as an annual mean measured in daily intervals, with 98% of observations below 120 pug m-3.731In the US the primary air-quality standard for TSP is 75 pg m - 3 (annual geometric mean, 24 h values), with 260 pg m-3 as a 24 h value not to be exceeded more than once a year;’2a a standard for the fine particle fraction of TSP is under review. Dangers of pneumoconiosis from dust in quarries have been assessed by comparison with the UK coal mines (respirable dust) limit of 4.3 mg dust rnb3 at the coal face, that contains ( 5 % A pollutant standards index (PSI) based on TSP and levels of four gaseous pollutants gives a dimensionless value intended for public information purposes;732 the PSI concept and guidelines are approved by the EPA.733For example, a daily air-quality index is published by the New Jersey Bureau of Air Pollution Control, In Canada, good correlations based on measurement of TSP, SO,, and are reported between hospital admissions for respiratory complaints and a calculated air-pollution index (API) from measurements of haze and Subsequently, a new urban air-quality index was applied to 11 Canadian cities, taking into account both the magnitude and frequency of short-term (daily) pollution episodes and also annual concentrations of pollutants, namely TSP, SO,, CO, NO,, and 03.736 Effects on man of exposure to H,S04 aerosols and SO:- have

’”‘Air Pollution’.

3rd Edn., Vol. 5, ‘Air Quality Management’. ed. A. C . Stern, Academic Press, New Ynrk, 1977. de Nevers. J . Air Pollut. Control Assoc., 1977, 27. 197. US Environ. Protection Agency, Federal Regisier. 1978. 43. 9452. 7 2 h S L. Wilcox, E. L. Keitz. and L. J. Duncan. in ref. 88, p. 124 I . 72”lmpact of Energy Production on Human Health‘. ed. E. C. Anderson and E. M. Sullivan, USERDA Symp. Ser. 39. NTIS, Springfield, VA. 1976. 12’ B. G. Ferris, J . Air Pollut. Control Assoc., 1978. 28.482. 7 2 y H. Kolb, We//erLeben, 1978. 30, 230. W. R. Ott and G. C. Thom, J . Air Pollut. ControlAssoc.. 1976, 26,460. 7 3 ’ M. J . Gittins, Clean Air, 1978. 8, 19. 7 3 * W. R. Ott and W. F. Hunt. jun., J . Air Pollui. Control Assoc., 1976, 11, 1050. ’ j 3 US Environ. Protection Agency, Publ. EPA-450/2-76-013. N. Carolina, 1976. 7 3 4 V. J. Marchesani, J. N. DePierro, T. A. Juchnowski, R. J. Pfannenstiel, J. J. Serkies, and A. S. Thornton, Atmos. Environ.. 1975. 9. 683. 7 3 5 D. Levy, M. Gent, and M. Newhouse, in ref. 88, p. 1263. 7 3 h M. H. Doan and C. East, WaferAir Soil Polhi., 1977. 8, 4 4 I .

724

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been discussed r e ~ e n t l y ,although ~ guidelines are not yet available from W . H . 0 . 5 The secondary nature of these pollutants presents a complex problem, but it is considered that in the first instance, standards could be based on total water-soluble SO$- in air particulates, perhaps within the range 5-15 pg m-) as an annual average. 7 3 7 A Cumulative Hazard Index (CUMEX) has been developed to assess intake and absorption of single pollutants by man, and is applied to releases of Cd by a smelter The index is the ratio of integrated exposure to the body or critical organ to the limit assigned from considerations of health risk. Hazards to man from airborne metals have sometimes been estimated by comparison with Threshold Limit Values (TLV) for the workroom e n v i r o n m e r ~ t ,by ~ ~using ~ . ~ ~h ~t h of the TLV as a guideline for maximum acceptable levels in the ambient atmosphere, although this is not specifically recommended by the originators of T L V ' S . It ~ ~is~noted that in urban areas, Pb concentrations may reach 1% of the TLV for industrial workers, a level not usually attained by other metals.741 National ambient air-quality standards for metals have been summarized;723in 1979 the USEPA issued a revised standard of 1.5 pg Pb mP3 (based on 3 month average) intended to prevent levels in children's blood exceeding 30 pug Pb/100 ml.742In some countries, standards are set for deposited particulates,723e.g., 0.65 g rn-' day-' (as monthly average) in W. Germany. Effects on Visibility.-A reduction in visual range in the atmosphere, caused by an increase in airborne particles that affects light scattering and attenuation, involves both primary and secondary aerosols, and may be experienced in rural as well as urban area^.^^^*^^^*^^^ The implications for agriculture of reduction in intensity of light at ground level have been ons side red,^^^,^^^ in addition to requirements of a visibility impairment model to assess the impact of near-source and regional pollution by excessive particulate loadings.746However, visual opacity of smoke plumes is not well related to mass emissions of particulates and other factors such as physical properties of the TSP and observer location must also be considered to avoid rni~interpretation.~~~ Particulates have sometimes caused atmospheric discolouration by wavelength-dependent light scattering as in Los Angeles smog.748

M. D. Rowe. S. C . Morris, and L. D. Hamilton. J . A i r Pollut. Control Assoc., 1978, 28. 772. P. J . Walsh, G. G . Killough, D. C . Parzyck, P. S. Rohwer, E. M . Rupp, B. L. Whitfield. R. S. Booth, and R. J . Raridon, Rep. O R N L 5263. Oak Ridge Natl. Lab., Tennessee. 1977. '" 'Threshold Limits for Chemical Substances in Workroom Air', Am. Conf. Govt. Indust. Hygienists, Cincinnati, Ohio. 1979. 74"'Threshold Limit Values for 1977', Health and Safety Executive Guidance Note EH 15/77, H.S.E., London. 1977. ''' 'Pollution in the Atmosphere', Study Group Rep. R. Soc., London, 1978. 742 'Air Quality Criteria for Lead'. US Environ. Protection Agency, N. Carolina, 1978. 7 4 ' C . N. Davies, J . Aerosol Sci.. 1975, 6, 335. 744 H. A. Bridgman. Solar Energy, 1978, 21, 139. 745 Report E R D A - 12 17-75. Chemist/Meteorologist Workshop (USERDA), NTIS, Springfield, VA, 1975. 74h R. W . Bergstrom and D. A. Latimer, in 'Proc. 3rd Conf. Atmos. Radiat.', Am. Met. Soc., Boston, 1978. p. 14. 747 A. Weir, jun., D. G . Jones. L. T. Papay, S. Calvert. and S. C. Yung, Enzyiron. Sci. Techno/., 1976. 10, 539. 74R R. B. Husar and W . H . White, Amos. Enzliron.. 1976. 10, 199.

'j7

"*

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In rural areas, constants relating visibility to the mass concentration of particles showed wide variation between 2 x lo-* and 1 x lo-’ g m-3 km during wind erosion of soil, with higher values under drought conditions, and it proved difficult to predict mass concentrations of dust from measurements of ~isibility.’~~ In an urban aerosol analysed for particle-size associations of 8 elements and total mass at four levels of visibility, it was found that increases in fine particles (d = 0.1-1 pm) were particularly associated with a decrease in visibility and that these contained high mass concentrations of SO:- relative to NO;, C1, NH:, and C.750At a visual range of 8-13 km the TSP load was 232 pg m-3 compared with 59 pg mP3for visual range >26 km in a background area.75oSignificant effects of SO:- aerosols on reduction in visibility are reported by other w o r k e r ~ ~ ~ and l *G ~ e~ ~* r g i i ~ has *~ reviewed the sources, global distribution, and effects of SO:- particles on light scattering and absorption. Photochemical pollution in London in 1976 was considered a major factor in formation of haze,753and reduction in visibility caused by SO:- aerosols in photochemical smog is particularly evident at low humidities.754 In Los Angeles aerosol, SO:- and NO; contributed nearly 60% to the total m-1.755 light-scattering coefficient (b,,,,) of 6.4 x Examination of air trajectories over Sweden has shown that maximum light scattering and absorption is coincidental with peak levels of SO:-, NH:, and TSP loading experienced during airflow from S.E. to W. In the stratosphere, formation of haze clouds at 25 km altitutde in the absence of volcanic dust incursions are believed to result from interchange of particles across the tropopau~e.~~~ Effects on the Global Albedo and Climate.-Increases in particulate matter in the atmosphere may affect cloud droplet formation and precipitation, reduce the amount of solar radiation that reaches the ground, reduce the cooling of the surface layer of the earth at night and influence the global However, controversy still remains as to whether the presence of particulate material exerts a net warming or cooling effect to enhance or offset the global warming predicted In general it is from increases in CO, and chlorofluoromethanes in the atm~sphere.~ believed that aerosols are less important than CO, with respect to the global heat balance although regional effects of high TSP are not excluded.762In addition,

E. M. Patterson and D. A. Gillette, Atmos. Enuiron., 1977, 11, 193. R. K. Patterson and J. Wagman, J. Aerosol Sci., 1977,8,269. 7 5 1 J. B. Barone, T. A. Cahill, R. A. Eldred, R. G. Flocchini, D. J. Shadoan, and T. M. Dietz, Amos. Enuiron., 1978, 12,2213. 752 B. P. Leaderer, T. R. Holford, and J. A. J. Stolwijk, J . Air Pollut. Control Assoc., 1979, 29, 154. 753 D. J. Ball and R. E. Bernard, Nature (London), 1978,271, 733. 754 W. H. White, Nature (London), 1976, 264, 735. 755 W. H. White and P. T. Roberts, Atmos. Enuiron., 1977, 11, 803. 756 J. Heintzenberg and C. Tragardh, Rep. AC-48, Dept. Meteorology, Internat. Meteorol. Inst., Univ. Stockholm, 1979. 757 F. W. Gibson, Nature (London), 1976, 263,487. 758 L. A. Barrie, D. M. Whelpdale, and R. E. Munn, Ambio, 1976, 5 , 209. 7 5 9 G. D. Robinson, in ‘Energy and Climate’, Natl. Acad. Sci., Washington DC, 1977, p. 61. 760 H. Hidalgo, IEEE Trans. Geosci. Electron., 1978, 16,4. 761 E. W. Barrett, IEEE Trans. Geosci. Electron., 1978, 16, 62. 762 W. W. Kellogg and S. H. Schneider, IEEE Trans. Geosci. Electron., 1978, 16,44.

749

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65

considerable changes in global and surface albedo have been caused by deforestation, salinization, and d e ~ e r t i f i c a t i o n .As ~ ~ Flohn ~ 764 has pointed out, the role of particulates and CO, on global temperature changes must be viewed against a background of natural effects such as volcanic eruptions and changes in Arctic sea ice, snow cover, and oceanic evaporation. Bolin and Charlson 765 reported that scattering of solar radiation by tropospheric SO:- aerosols might lower the average temperature of the N. hemisphere by 0.1 "C, excluding any effects of this aerosol on the infrared flux or on cloud formation. Some workers believe that with less particulate pollution, by emissions controls on industry, a cooling effect of particles will no longer offset global warming (greenhouse effect) from anthropogenic emissions of CO,, with the possibility of -0.5 "C increase from 1970 to 2000.766 From an inventory of particulate production estimates and a historical summary of anthropogenic aerosols and climatic change, Dittberner 7 6 7 considers that the importance of volcanic emissions, industrial-derived aerosols, and CO, on climatic change is roughly comparable. A layer of Sahara dust over the Cape Verde Is. in July 1974 depleted -20% of the direct solar energy flux mainly by absorption but with some b a c k s ~ a t t e r i n g . ~ ~ ~ The estimated average solar heating rate of a Sahara dust layer at 1-5 km over the tropical Atlantic (for optical depth 2.0,and dust loading of 7.5 g rn-, under clear sky conditions) was 3.1 "C day-', rising to 4.3 "C day-' with overcast conditions below the dust layer base:769this aerosol absorbs strongly in the short-wave region of the solar spectrum so that increasing dust load gives relatively large heating rates in the lower troposphere and cooling near the A modified radiative transfer model has been used to examine the effects of heavy dust layers on infrared radiative cooling of arid regions with special reference to the Rajasthan Desert in N.W. India and indicates an increase in such cooling in the lower troposphere of Modifications by cloud layers to the influence of aerosols on the radiative heat balance of the earth have been e ~ a m i n e d . ~ ~ ~ . ~ ~ ~ With respect to the influence of stratospheric aerosols on climate, the presence of submicrometre particles derived mainly from volcanic activity and supersonic transports (SSTs), having long residence times of -3-10 yr, has received a t t e n t i ~ n . Past ~ ~ ~volcanic - ~ ~ ~ activity such as the 1963 Mt. Agung eruption are well correlated with elevated atmospheric heating rates and a temporary reduction in surface temperatures of the earth, whereas such climatic impact is not anticipated

-

C. Sagan, 0. B. Toon, and J. B. Pollock, Science, 1979,206, 1363. H. Flohn, in 'Global Chemical Cycles and their Alteration by Man', ed. W. Stumm, Dahlem Konferenzen, Berlin, 1977, p. 207. 765 B. Bolin and R. J. Charlson, Ambio, 1976, 5,47. 766 M. I. Budyko and K. Ya. Vinnikov, in ref. 764, p. 190. 767 G. J. Dittberner, IEEE Trans. Geosci. Electron, 1978, 16,50. 768T. N. Carlson and R. S. Caverly,J. Geophys. Res., 1977, 82, 3141. 769 T. N. Carlson and R. S . Caverly. in ref. 113, p. 160. 710 Harshvardhan and R. D. Cess, J . Quant. Spectrosc. Radiat. Transfer, 1978, 19,621. 7 7 1 S. Moriyama, Atmos. Environ., 1978, 12, 1875. 772 Harshvardhan and R. D. Cess, Tellus, 1976, 28, 1. 7 7 3 B. M. Herman, S . R. Browning, and R. Rabinoff,J. Appl. Meteorol., 1976, 15. 1057. 774 J. A. Coakley and G. W. Grams,J. Appl. Meteorol., 1976, 15,679. 775 J. Bensimon and B. Dehove, Met. (Paris) 6th Ser., 1977, No. 10, 15. 763

764


66 2600 i2200

1400 1200

1800

1000

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800

LL 0

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600

1000

1400 I I I I I 600 I 19461950 1954 1958 1962 1966 1970 1974

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Figure5 Injuence of volcanic dust at high latitudes. Annual (T, + T,) MDD totals at Thule, northwestern Greenland, showing the abrupt decrease in overall Summer warmth' after the eruption of Mount Agung in 1963. A melting degree day ( M D D ) is the difference between 0 " C and daily maximum (T,MDD) or minimum (T, MDD) temperatures, wher?the latter are above 0 "C (Reproduced by permission from Nature (London), 1978,271,735)

from S S T S . Observations ~~~ of the number and SO:- content of volcanic dust bands in ice cores from Greenland and Antarctica indicate the important influence of volcanic activity on cooling during the 'Little Ice Age' (- 1450-19 15) and on later stages of the last major ice age (the Wisconsin, -75 000-12 000 BP).F76 Details of 28 volcanic eruptions between 1883 and 1968 that caused stratospheric dust injections over latitudes 39"s to 64"N are listed by Oliver.777 From a study of the stratospheric dust veil index (DVI: a time- and area-weighted radiation loss parameter) and CO, levels from 1870-1969, it was found that these factors accounted for 65% of the variance in N. hemisphere temperature^.^^^,^'^ Values of DVI in the N. hemisphere in the mid-1960's were 1100 (after Mt. Agung event), the greatest since the eruption of Krakatau in 1883, which gave DVI values of 1500;7R0high levels of diffuse radiation after 1964 and relatively low values of direct solar radiation, typical of volcanic dust, appear to have decreased the summer warmth in the Canadian Arctic (Figure 5) with the result that melting of snow and ice is reduced7*0 (Figure 6). Heterogeneous reactions between volcanicderived particles and trace gases such as C1 injected to the stratosphere possibly cause ozone column depletion of < 1% for a major eruption equal to Mt. A g ~ n g . ~ ~ ' Inadvertent modification of climate on a local, regional, and global scale by enhanced formation of cloud condensation nuclei (CCN) and ice nuclei (IN) also demands c ~ n s i d e r a t i o n . ~In~ ' the US east coast region, CCN concentrations in urban air were from 1000-3500 crnp3, an order of magnitude greater than in continental or maritime atmospheres.782On a global scale, formation of CCN from B. Baldwin. J. B. Pollack, A. Summers. 0. B. Toon. C. Sagan, and W. Van Camp, Nature (London). 1976,263,551. 7 7 7 R. C. Oliver, J . Appl. Meteorol., 1976, 15, 993. "* M. K. Miles and P. B. Gildersleeves. Meteorol. Magazine, 1977. 106, 314. 7 7 9 M. K. Miles and P . B. Gildersleeves. Nafure (London), 1978, 271, 735. 7Rfl R. S. Bradley and J . England, Nature (London), 1978, 271. 736. 7 8 1 R. S. Stolarski and D. M . Butler, Pure A p p l . Geophys. (Bade). 1979. 117, 486. 782 L. F. Radke and P. V . Hobbs, Science, 1976, 193. 999. 776

lnorganic Particulate Matter in the Atmosphere

67

0 -500

- 1000

-1 500 NI

E 0

A

-2000 -2500

-3000

-3500

-4000

I

1

1

1

1

1

1

1950 1955

1

~

l1 , , , , I , , * , l , , , ,

1960 1965 1970

Figure 6 Glacier mass balance at high latitudes. Reconstruction of cumulative mass loss on the north-west Devon Ice Cap since 1947. The abrupt change in net loss since 1963 is clearly shown (Reproduced by permission from Nature (London), 1978,271, 735)

anthropogenic sources may be comparable to a natural production rate of s - ’ . ~ ~Basic , processes by which ice-forming nuclei induce vapour and liquid nucleation have been reviewed.783The formation of CCN in urban pollution episodes is accelerated by sunlight and results from coagulation and photolytic reactions to give larger, more water soluble particles.784 Project ‘Metromex’ was initiated in 1969 to study the influence of the St. Louis (Missouri) metropolitan area on temperature, cloud microstructure, and p r e ~ i p i t a t i o n plumes ; ~ ~ ~ of SO, undergo gas to particle conversion to form Aitken particles, which then grow to CCN. Zones of higher rainfall than the area average A scavenging effect of fog on CCN in are identified up to 30 km from the the St. Louis atmosphere has been shown by aircraft surveys with a CCN spectrometer.786An increase in rainfall downwind of industrial zones of Bombay is also related to greater numbers of CCN.787Plumes from paper mills increased the concentrations of large (d = 0.1-1 pm) and giant (d > 1 pm) CCN by five-fold with a corresponding increase in concentrations of large droplets (d 2 30 pm) in clouds located in the plume, that results in frequent rain showers at 2-5 km H. K . Weickmann, in ‘Proc. 3rd Int. Workshop Ice Nucleus Measurements’, ed. G . Vali, UGGI/IAMAP, 1976, p. 16. 784 C. C. Van Valin, R. F. Pueschel, F. P. Parungo, and R. A. Proulx, Atmos. Environ., 1976, 10, 21. 78s R. R. Braham, in Proc. 2nd W.M.O. Scient. Conf. Weather Modification, W.M.O. Rep. 443, Geneva, 1976, p. 435. m6 V. K. Saxena, in ref. 30, p. 152. 787 A. M. Selvam, A. S . Ramachandra Murty, S. K. Paul, R. Vijayakumar, and Bh. V. Ramana Murty, Atmos. Environ., 1978, 12, 1097. 783

68


downwind.’** The evidence for effects of power stations on precipitation has been summarized. 789 Submicrometre aerosols emitted from a copper smelter were reported as active CCN, although the relatively narrow size distribution inhibits coalescence and consequently a haze or fog may appear.79oThe fact that more IN appeared downwind was explained by near-distance deactivation of plume aerosols by gaseous emissions, such as SO, and NO,, that volatilize during dispersion to distant regions.79oWith reference to fly ash, if the volatile surface coating is evaporated, it enhances the relatively poor ability of these particles as IN.136Analysis of active IN from rocket exhaust aerosol indicated that most contain mixed particles of Al, Ca, and S.791 It is proposed that weather could be modified on a mesoscale by dispersal of submicrometre carbon particles in the upper troposphere.792This would absorb solar energy and assist cirrus cloud formation, leading to a lower daytime surface temperature of benefit to agriculture in certain seasons. A reduction in long-wave radiative cooling at night would lessen damage by frost.

8 Future Research Needs and Conclusions Recognition of the potential for long-distance transport of pollutants in the atmosphere and their complex effects on biological systems has helped to initiate interdisciplinary studies in recent years, and continued attention has been given to control of emissions by industry. In 1977 approval was made for continuation of the European Communities Environmental ‘Programme of Action’ designed to develop environmental quality objectives and standards for control of air and water pollution, to examine global aspects of pollution, and to study management of natural resources.793 Requirements for atmospheric pollution research on global, regional, and local scales were reviewed by a Royal Society Study areas for further work on inorganic particulates were identified as ( i ) high altitude aerosols and their influence on climate, (ii) removal and effects of metals and SO, deposited to soil, plants, and water, (iii) impact of accidental discharges, and (iv) transport processes. In the US, recommendations have been made for research to assess the environmental effects of fossil-fuel combustion in the next decade.794 The significance of climatic change following increases in particulate matter and CO, in the atmosphere is not well established, although these factors have been implicated with expansion of the Sahara desert into agricultural regions.795Recent eruptions of Mount St. Helens volcano, Washington, in May 1980 have made substantial contributions to the stratospheric dust and modern remote sensing techniques should yield valuable data on dust trajectories and residence times of particulates.

”’ E. E. Hindman, P. M. Tag, B. A. Silverman, and P. V. Hobbs, in ref. 785, p. 21. S . R. Hanna, in ref. 519, p. 88. F. Parungo and R. Pueschel, in ref. 30, p. 156. 79‘ F. Parungo and P. A. Allee, . I Appl. . Meteorol., 1978, 17, 1856. 792 W. M. Gray, W. M. Frank, M. L. Corrin, and C. A. Stokes, in ref. 785, p. 425.

789 790

CEC, ‘State of the Environment’, 2nd Rep., E.E.C. Luxembourg, 1979. D. Cohan and D. W. North, Rep. EA-1018, Electric Power Res. Inst., Palo Alto, CA, 1979. 7 9 5 J. 0. Ayoade, Arch. Meterol. Geoph. Bioklimatol. Ser. B., 1971, 25, 61. 796 A. Tucker, Manchester Guardian, 1980, 2nd June, p. 3. 793 794


69

Improved information is needed on biogeochemical cycling of elements for an accurate appreciation of disturbances caused by excessive release to the atmosphere and subsequent deposition to terrestrial and aquatic ecosystems; it is now believed that the rainfall flux of Hg to the open ocean has been over-estimated by more than an order of magnitude.797The removal rates of pollutants from the atmosphere by wet and dry deposition should be examined in detail under seasonal conditions that influence soil and plant cover. Little information exists on the chemical forms and oxidation states of metals in air and rainwater. Detailed recommendations for further research into sulphur emission, behaviour, and modelling were made by four workshops following the Dubrovnik Symposium.798Since the oxidation of SO, to SO$ can be catalysed by Mn and other metals, studies on the transport and fate of SO, should consider the concentrations of particulate metals in the atmosphere. New combined techniques of microscopy and multi-element analysis are proving extremely valuable to characterize particles emitted by natural and industrial sources. Wider application of these methods is anticipated to examine the distribution and correlations of elements in particle-size modes, and particulate composition in relation to sources and air-mass trajectories. Intercalibration of sampling and analytical methods is essential, particularly to improve the reliability of global monitoring and international projects on transport of pollutants. Application of physical and chemical methods of analysis to measurements in the field could reduce problems of sample contamination and deterioration in storage. Continuous measurement of airborne particulate matter is essential in urban areas to record high episodic levels of pollutants and for public reassurance on health risks. Information on long-term trends in concentrations of pollutants is required to relate to changes in major industrial activities and energy production. Development and application of personal air monitors is important to improve exposure estimates of residents to elements in urban areas within which the pollution levels may be very variable.745The Health and Safety Commission has recently advised that exposure of individuals to asbestos in the non-occupational environment should be measured.65 The possibility of synergistic effects of pollutants on human health requires careful attention; urban pollution being seldom restricted to single elements or gaseous species. Entry of airborne metal pollutants into the body by ingestion of contaminated vegetables and water, in addition to inhalation, has received little attention in studies on urban pollution but may contribute significantly to the intake of metals such as Cd and Pb.

Acknowledgments. I am very grateful to Mrs. Joyce Cowlard, Meteorological Office Library, Bracknell, Berks., and Margaret Cann, Environmental and Medical Sciences Division, AERE, Harwell for their co-operation with the literature survey work I carried out within the scope of this review.

'" T. R. Fogg and W. F. Fitzgerald, J . Geophys. Res., 1979,84,6987. '"Anon., Atmos. Environ., 1978, 12, I .

The Elemental Content of H u m a n Diets and Excreta BY H. J. M. BOWEN

1 Introduction The inorganic constituents of human diets have been studied for two reasons. Diets deficient in any of the essential elements can lead to numerous and varied malfunctions, which can often be cured by restoring the missing element.’V2Diets containing excessive amounts of almost any element can be toxic, but a change to a normal diet may not relieve the toxic symptoms quickly, as the retention time in the body may be long. Although information about the tolerable limits of concentration of elements in diets is meagre, it seems that both deficient and toxic diets are rare and local among human populations, and are more often seen in animals.2 2 Outline of Ingestion, Absorption, and Excretion The physiology of ingestion and excretion is too well known to need further description. Normal adults are in a steady state with respect to elemental inputs and outputs. Reference Man, a convenient fiction supposed to weigh 70 kg, is assumed to eat 750 g dry matter and drink 1.95 1 water per day; his excretion averages 30 g faeces (dry matter) and 1.4 1 urine per day.3 He also breathes 23 m3 of air each day, which contains traces of all the chemical elements. However, for almost all the elements more than 90% of the mass ingested comes from food. In exceptional localities, drinking water can provide a significant fraction of the intake of a r s e n i ~ , ~ f l ~ o r i n e ,selenium,6 ~ and uranium.’ Excretion in sweat, in hair, or in other ways appear to be of minor importance compared with urine and faecese3 Human diets are notoriously variable, but data on the relative proportions of the

’ A. S. Prasad and D. Oberleas (ed.), ‘Trace Elements in Human Health and Disease’, Academic Press, London, 1976. J. Underwood, ‘Trace Elements in Human and Animal Nutrition’, 4th Edn., Academic Press, London, 1977. W. S. Snyder (ed.), ‘Report of Task Group on Reference Man’. Pergamon, London, 1975. J . M. Harrington, J . P. Middaugh, D. L. Morse, and J. Housworth, A m . J . Epidemiol., 1978, 108, 317. C . M. Jones, J. M. Harries, and A. E. Martin, J . Sci.Fd. Agric., 1971, 22, 602. I. Rosenfeld and 0. A. Beath, ‘Selenium’, Academic Press, London, 1964. p. 286. A. V. Berdnikova, Vopr. Pitan., 1964, 23, 17.

* E.

70

The Elemental Content of Human Diets and Excreta

71

main components are available for some countries.8*yAs most common foodstuffs have been analysed, some authors have combined data to calculate average dietary intakes from these countries.'O Examples of diets with abnormal amounts of trace elements include those containing unusual amounts of sea food (rich in As, Br, Cd, Hg, I, Se, and Zn) or Brazil nuts (rich in Ba, Se, and Sr). Urban and institutional diets have been most studied, and since the food sources are numerous and widespread it is perhaps not surprising that their elemental contents are similar all over the world. More studies are needed on rural populations living almost exclusively on local foods. These can illustrate surprising results, such as zinc deficiency in Iran and excessive iron in parts of Africa,l3~l4and selenium toxicity in Colombia.6*l 5 Selenium deficiency has recently been reported in part of China (see ref. 101). Although specified concentrations of elements such as iron and zinc have been recommended in the USA,' it has not been proved that these apply to all individuals or to all countries. In particular, countries where the mean adult weight is lower than in the USA may have lower dietary requirements. Since few human feeding experiments are carried out for periods of more than one year (0.015 x lifetime), evidence on this point is hard to obtain. A few hospital patients are fed on artificial diets of constant elemental composition, but a recent review concludes that these are not cost effective (see ref. 262). While measurements of the masses of food ingested are straightforward, estimates of elemental absorption across the gut wall are more controversial. As a rough approximation, we can estimate the percentage absorption of any element across the gut from the ratio of urinary excretion to dietary intake. This is a fairly good approximation for mobile, rapidly metabolized elements, but takes no account of two side effects. These are (i) re-excretion of absorbed elements from the bile duct into the faeces, and (ii) the long retention times of some absorbed elements by specific organs, e.g., cadmium in kidney; iron in ferritin; barium, calcium, lead, strontium, etc. in bone.I6 A powerful method for studying absorption and retention by the body involves the occupancy principle. l 7 This method, which compares the oral and intravenous administration of radioactive tracers, has been used to show that the bromide ion is almost totally absorbed across the gut wa11.18 Note that the inhalation of elements into the lung can be the equivalent of an intravenous injection, so that inhalation of poisonous materials is more hazardous than ingesting them orally. However most F.A.O., Per capita food consumption data, Food balance sheets, average for 1964-6, Food and Agriculture Organization, Rome, 197 1. J . T. Tanner and M. H. Friedman,J. Radioanal. Chem., 1977, 37. 529. l o G. N. Schrauzer, D. A. White, and C. J . Schneider. Bioinorg. Chern., 1977, 7. 35. H. A. Ronaghy, in 'Clinical Applications of Zinc Metabolism', ed. W. J . Pories, W. H. Strain, J. M. Hsu, and R. L. Woosley. C. C. Thomas, Springfield, IL, 1974. p. 119. l 2 A. S. Prasad, 'Trace Elements and Iron in Human Metabolism', J . Wiley, New York, 1978. l 3 C. I. Waslien in ref. I , VoI. 2, p. 347. l 4 D. J. Horvath, in 'Trace Substances and Health', ed. P. M. Newberne, M. Dekker, New York, 1976, p. 319. ''J. Ancizar-Sordo, Soil Sci.,1947, 63, 431. l 6 H. J. M. Bowen, 'Environmental Chemistry of the Elements', Academic Press. London. 1979. " J . S. Orr and F. C. Gillespie, Science, 1968, 162. 138. I s F. C. Gillespie, J. Shimmins, and J. M. A. Lenihan. Radiochem. Radioanal. L.eti.. 1970. 4, 43.


72

elements will be inhaled as particulate matter, whose rate of absorption from the lungs will be determined by the solubility of the particles in blood. In the Chemical Industry, toxicity is sometimes caused by inhalation of excessive As, Be, Cr, Mn, Ni, Pb, Sb, V, and other elements, but there is little quantitative data relating inhalation rates to t o ~ i c i t y . ’ ~ Investigations of absorption across the gut wall are hampered by our ignorance of the chemical nature of most elements in prepared or partially digested food. For example, much of the iron in the diet is ingested as pcrphyrin derivatives such as myoglobin, but it is not known how much of the metal is set free on digestion or which chemical form of iron is most readily absorbed. In addition common organic constituents of foods, such as phytates, have substantial effects on the absorption of calcium, iron,” and zinc.I2 Aluminium is not normally regarded as toxic,19but may become so in the diets of patients undergoing dialysis.*’ Organometallic derivatives of lead and mercury have quite different lipid solubilities from those of the cations of these metals, so that their percentage absorption is increased.’,22 This needs further study since it now appears that several B-Group elements, notably arsenic, selenium, and tin, can occur as methyl derivatives in the e n ~ i r o n r n e n t . ~ ~ - ~ ~ As well as interactions with organic substances, there are almost certainly many mutual interactions between elements with respect to human dietary ab~orption.~’ Examples of such interactions include copper and molybdenum,2 and mercury and selenium,2* which have been investigated in mammals other than man. It is worth pointing out here that any extrapolation from the diets of laboratory animals or farm stock to those of human beings must be interpreted with caution. Thus studies of rodents give useful information on elemental t o x i c i t i e ~but , ~ ~ are limited by the short life-span of the animals.30In experiments with farm animals, whose life-span is also much shorter than that of man, the possession of a rumen by cows and sheep makes their digestive system rather different. Grazing mammals ingest much more soil and atmospheric fall-out than do humans, and neither wash nor cook their food before they eat it.

3 Methodological Problems The collection of food samples, including daily diets, for analysis is subject to an uncertain degree of contamination from dust, container materials, and laboratory handling. 24-h urine samples can readily be obtained from inmates of institutions, E. Browning, ‘Toxicity of Industrial Metals’, 2nd Edn., Butterworths, London, 1969. S . R. Williams, ‘Nutrition and Diet Therapy’, C. V. Mosby, St Louis, MO, 1977. 2 1 H. L. Elliott, F. Dryburgh, G. S . Fell, and A. I. Macdougall, Br. Med. J., 1978, 1, 1101. 22 S . Moeschlin, ‘Poisoning’, Grune and Stratton, New York, 1965. 23 R. S . Braman and C. C . Foreback, Science, 1973, 182, 1247. 24 J. M. Wood, H. J. Segall, W. P. Ridley, A. Cheh, W. Chudyk, and J. S . Thayer, in ‘Heavy Metals in the Environment’, ed. T. C. Hutchinson, Toronto, 1975, Vol. 1, p. 49. M. 0. Andreae, Anal. Chem., 1977,49,820. 26 R. S . Braman and M. A. Tompkins, Anal. Chem., 1979,51, 12. 27 C. H. Hill, in ref. 1, Vol. 2, p. 28 1. 28 J. Parizek and I. Ostadalova, Experienria, 1967, 23, 142. 29 B. Venugopal and T. D. Luckey, ‘Metal Toxicity in Mammals’, Plenum Press. New York, 1978, Vol. 2. 30 H. A. Schroeder and D. K . Darrow, in ‘Chemical Analysis of the Environment and Other Modern Techniques’, ed. S . Ahuja, E. M. Cohen, et al., Plenum Press, New York, 1973. l9

2o

’’

73

The Elemental Content of Human Diets and Excreta Table 1 Elemental content of adult human diets mg X day-'

X

A g 0.07

Al

As

Country

0.027 tO.0004--0.007 0.002-0.016 0.04

Many UK Italy Sweden USA

0.02?

Median

45 (7-500) 2.3 0.04- 1.4 20 5.3-9

Many UK Sweden USA USA

I O?

Median

1

0. I 0.055 0.08 (0.006-0.19) 0.027 (0.014-0.04) 0.07-0. I7 0.32 0.23-0.75 calc. 0.0 I

Many UK Scotland Germany Austria Japan Korea Many USA

0. I

Median

Au (0.007 0.002 (.ProJ Pap., 1971, No. 574D: ' M . L. Berrow and R. L. Mitchell, Trans. R. SOC.Edinburgh: Earih Sci.. 1980. 71. 103: P. J. Lechler. W. R. Roy. and R. K . Leininger. Soil Sci., 1980. 130,238 I. C. Gupta. S. K. Singha, and G. P. Bhargava, 1.Indian Soc. Soil. Sci.. 1974, 22, 88. G. R. Bradford, in 'Diagnostic Criteria for Plants and Soils', ed. H. D. Chapman, University of California. 1966, p. 2 18. 47 G. R. Bradford, Soil Sci., 1963, 76. 77, 48 N. Wells and J. S. Whitton, N.Z. J . Sci., 1966, 9, 982. 49 F. A. Sneva. Plant Soil., 1979, 53, 219. 50 J . Bolton, J . Sci. Food Agric.. 1973, 24, 721. 4s

46

99

The Elemental Constituents of Soils

essential element and additions of sodium chloride to soils can provide increased yields of some plants. Some show no response to added sodium, some respond when K levels are low and others even when K levels are adequate. Some degree of overlap exists in the roles of Na and K in plant nutrition and this aspect is discussed in detail by Tinker.39

Potassium. The overall mean content of 2011 soils is 1.83% K, Table 3, with a The fact that the bulk of K in most soils is in the silt and range of 0.005-7.9%. clay fraction^^^.^^ accounts for the distribution of K in profiles. A correlation coefficient of 0.81 was obtained between the K and clay contents of an extensive range of 204 soils in Finland.52As depth increased from 0-30 to 40-1 10 cm in Armenian brown soils, K decreased from 1.5 to 1.1%.53Potassium is an essential element for plants and animals and its key role in agriculture is reflected in a vast literature on available, extractable, and exchangeable K in soils and its uptake by plants, an aspect not wholly pertinent to this work. General treatments of these aspects of K in soils, plants, and agriculture can be found for example in

Table 3 Potassium soil contents (% K) Soils Range 119 soils; compilation up to 1965 0.04-7.9 134 topsoils, S.W. Pacific 139 soils, Quebec, B-horizons 193 topsoils, USSR 0.7-3.8 863 topsoils, USA 0.005-7 USSR Chernozems I .86-2.2 1 15 1 soils, W. Indies 0.07-5.2 22 topsoils, India 0.79-1.36 4 topsoils, Malaya 0.03-1.19 102 surface soils, Finland 102 subsoils, Finland 40 Rice field soils, India 0.20-1.91 10 surface soils, India 0.82-2.4 0.90-1.86 10 subsoil, India Alluvial soils, Colombia/Venezuela 87 soils, Algeria, A horizons 23 soils, Scotland, 4 profiles 0.45-2.7 12 topsoils, S.E. USA 0.058-2.52 201 1 Soils Overall Mean 1.83% K

Mean 1.39 0.68 1.37 2.04 2.3 -

1.14 1.10 0.37 2.20 2.50 1.06 1.46 I .44 0.78 1.03 I .42 0.67

R ef: a 4 7 b 77 63* 59 57 50 52 52 58 C C

61 64 d e

* Not included in Mean ‘Handbook of Geochemistry’, ed. K. H . Wedepohl, 11-2/19; V. F. Brendakov, S. V. lokhelson, and V. N. Churkin, Soc. Soil Sci., 1967, (1). 3 1. ‘J. S. Choudhari and B. L. Pareek, J. Indian SOC.Soil Sci., 1976, 24, 57; M. L. Berrow and R. L. Mitchell, Trans. R . SOC.Edinburgh: Earth Sci.,1980. 71, 103; P. J. Lechler, W. R. Roy, and R. K. Leininger, Soil Sci.. 1980, 130, 238 a

’’M. I. Perevalov and N. N. Poddubnyi, Izv. Timiryazevsk. S’kh. Akad., 1974, No. 1, 74. 52

53

A. Kaila, J . Sci. Agric. SOC.,Finland, 1973, 45, 254. L. A. Araratyan, Biol. Z h . Armenia., 1971, 24, 75.


100

references.39354-56 Recent publications on the K status of agricultural soils include 5 8 Finland,52 West in die^,^^ Ghana,60 Colombia/ studies on soils of India,57* Venezuela,61 Tonga,62 USSR,5’363and Algeria.64 The effect of controlled fire in increasing the topsoil K content has been disc~ssed.~’

Rubidium. The range of Rb contents in Table 4 was 1.5-1800 mg kgg’ and the mean content of Rb calculated for some 972 soils was 120 mg kg-’, in good agreement with the mean of 140 given in an earlier c ~ m p i l a t i o nRubidium .~~ is not an essential element but is taken up by plants. In plants a K :Rb ratio of 1000 has been indicated.66 Caesium. Information on Cs contents of soils is scant although early workers indicated a range of 0.3-25.7 mg kg-’ for soils of France and Italy,67a mean value Table 4 Rubidium soil contents (mg Rb kg-’) Soils Range Compilation up to 1965 1.5- 1800 4 1 soils, Scotland, 8 profiles 30- 1500 139 soils, Quebec, B horizon 113 soils, Madagascar, 26 profiles 10-920 110 soils, Cameroon, 18 profiles 22.6-225 7 soils, Brazil 4-80 40 soils, Bulgaria 63-420 259 topsoils, Wales 29- 160 230 subsoils, Wales 47-170 10 topsoils, Scotland, Different parent mat. 35-190 23 soils, Scotland, 4 profiles 6-150 972 Soils Overall Mean 120 mg Rb kg-’

Mean 140 302 100 212 96.3 30 179 89 99 91 60

Re$ a* 3 7 22 23 6 c

d d e

f

* Not included in Mean ‘Handbook of Geochemistry’, ed. K. H. Wedepohl, 11-4/37: C. C. Dantas and H. Ruf, Radiochim. Aria, 1975, 22, 192; “ M . Naidenov and A. Travesi, Soil Sci., 1977, 124, 152; “ R . I. Bradley, C. C. Rudeforth, and C. Wilkins, J . Soil Sci., 1978, 29, 258; ’ A . M. Ure, J . R. Bacon, M. L. Berrow, and J. J. Watt, Geoderma, 1979, 22, I ; ’M. L. Berrow and R. L. Mitchell, Trans. R . Soc. Edinburgh: Earth Sci., 1980, 71, 103 Ministry of Agric., Fish and Food Tech. Bull., HMSO, London, 1967, No. 14, 195 pp. V . J. Kilmer, S . E. Younts, and N. C. Brady (ed.), ‘Role of Potassium in Agriculture’, Am. SOC. Agron., Crop Sci. SOC.Am., Soil Sci. SOC.Am., Madison, Wisc. USA., 1968, 509 pp. 5‘ Ministry of Agric. Fish and Food., Tech. Bull. ‘Residual Value of Applied Nutrients’, HMSO, London, 1971, No. 20. 5 7 R. K. Bhatnagar, G. P. Nathani, S. S. Chouhan, and S. P. Seth, J . Indian Soc. Soil Sci., 1973, 21, 429. ” S. S. Devi and R. S. Ayer, J . Indian SOC.Soil Sci., 1974, 22, 32. 5 9 N. Ahmad, I. S. Cornforth, and D. Walmsley, Plant Soil, 1973, 39,635. 6o D. K. Acquaye, Proc. 10th Colloq. Internat. Potass. Inst. Abidjan., 1973, 51. T. F. Fuentes and J. J. Gamboa, Turrialba., 1975,25, 371. R. Lee and J. P. Widdowson, Trop. Agric., 1977, 54, 25 1. 6 3 P. G. Aderikhin and A. B. Belyaev, Pochuovedenie., 1973, No. 10.99. “ H. Mutscher, Beitr. Trop. Landwirtsch. Veterinarmed., 1978, No. 1.43. J. R. Boyle, Commun. Soil.Sci. Plant Anal., 1973, 4, 369. “ M. Florkin and H. S. Mason, (ed.), ‘Comparative Biochemistry IV’, Academic Press, New York, 1962. G. Bertrand and D. Bertrand. C.R. Hebd. Seances Acad. Sci., 1949, 229, 533. 54 55

‘’

‘’


101

of 5 mg kg-' for soils of the Russian plain, and 1 mg kg-' for Japanese soils.68 Recent work on 10 Scottish topsoils derived from different materials gives an average Cs content of 3.6 mg kg-' and a range of 1.7-5.7 mg kg-1,69 while 4 Brazilian soils had a mean content of 2.25 mg kg-' and a range of 0.6-6 mg kg-'.70 The average Cs content of soils can only be assigned, therefore, a tentative value of about 3 mg kg-'.

3 The Alkaline Earth Elements: Beryllium, Magnesium, Calcium, Strontium, and Barium Beryllium.-Geochemistry. Beryllium is more abundant in siliceous than in subsilicic rocks and is highly accumulated in alkalic rocks. The Be content of ultrabasic rocks averages < 0.25 mg kg-', while in granitic rocks it varies from 1 to about 30 mg kg-I, averaging about 5 mg kg-'. In intermediate rocks Be contents of more than 10 mg kg-' are produced by metasomatic processes. In granitic rocks micaceous minerals such as muscovite have relatively high Be contents of up to 50 mg kg-'.71 Weathering and Mobility. The most abundant Be minerals, beryl or chrysoberyl, are highly insoluble. During weathering, however, a fraction of the primary Be is mobilized and partly fixed in clay minerals. Clay minerals from weathered alkalic rocks can contain about 100 mg Be kg-', while bauxites and clay minerals formed by the weathering of Be-rich rocks contain up to 60 and 100 mg Be kg-', respectively. Be and Sr were lost during the weathering of the Carmenellis granite, C~rnwall.~* Soil Contents. L i ~ reports k ~ ~ the approximate concentration of Be in soils to be 6 mg kg-', while B ~ w e n reports '~ a median of 0.3 mg kg-I and a range of 0.01-40 mg kg-'. The crustal average for Be is 2.6 mg kg-1.75 A d e t a i l e d ' s t ~ d yof~ ~the pedochemistry of Be in soils of the Black Forest showed that the Be content increased from sand to silt to clay. The pedochemical behaviour of Be was found to be very similar to that of A1 and it was shown that Be was not incorporated into soil humus. The uptake of Be by spruce was very low even in soils of pH as low as 5. The total Be contents in thirteen profile subsoils ranged from 2.5 to 8.7, mean 4.6 mg kg-'.76 Total contents in 863 surface soils from the USA ranged from < 1 to 7, mean 1 mg kg-1,77in 14 surface soils from Japan 0.5 to 1.95, mean 1.32 mg kg-1,78

A. P. Vinogradov, 'The Geochemistry of Rare and Dispersed Chemical Elements in Soils', Consultants Bureau, New York, 1959. 69 A. M. Ure, J. R. Bacon, M. L. Berrow, and J. J. Watt, Geoderma, 1979,22, 1 . 'O C . C . Dantas and H. Ruf, Radiochim. Actu, 1975,22, 192. 7 1 K . H. Wedepohl (ed.), 'Handbook of Geochemistry', 11- 1/4, Springer Verlag, Berlin. " C. M. Rice, Mineral Mag., 1973, 39,429. l 3 D. J. Lisk, Adv. Agron., 1972, 24, 267. 74 H. J. M. Bowen, 'Environmental Chemistry of the Elements', Academic Press, London, 1979. l J S. R. Taylor, Geochim. Cosmochim. Acta, 1964, 28, 1273. 76 K. Keilen, K. Stahr, H. von den Goltz, and H. W. Zottl, Geoderma, 1977, 17, 3 15. 7 7 H. T. Shacklette, J. C. Hamilton, J . G. Boerngen, and J . M. Bowles, US Geol. Surv. Prof: Pap., GPO, Washington DC, 1971, No. 574-D. la T. Asami, J . Sci. Soil.Manure, Jpn., 1975,46,421. 68

102


and in 10 surface soils from Scotland 0.8 to 5.6, mean 2.7 mg kg-1.6y In 41 samples from eight Scottish soil profiles total Be ranged from < 5 to 30, mean 6.2 mg kg--1,3 while in 19 samples from four German profiles total Be ranged from < 3 to 10, mean 3.7 mg kg- ' (see ref. 8 I). On the basis of these analyses a tentative value of about 1.5 mg kg-I might be suggested as a mean soil content. Beryllium is accumulated in coals compared with detrital sedimentary rocks. Be in coals is generally inversely correlated with ash content suggesting that the Be occurs mainly associated with organic ~ e s i d u e s . ~Be ' is taken up by plants from high-Be soils but is generally accumulated in the roots and not readily translocated to other tissue^.'^ Be was found to be toxic to plants in an acid sandy loam but was not toxic in a soil containing free calcium carbonate.RoBe is toxic to humans and animals.

Magnesium.-Geochemistry. Magnesium is an important constituent of a large number of common rock-forming silicates i.e., olivines, pyroxenes, amphiboles, and micaceous and clay silicates. It also forms a large variety of carbonate minerals. Magnesium is relatively concentrated in the early crystalline precipitates in igneous rocks and there is a steady decrease in the Mg content through the calc-alkali series rocks ranging from gabbro to granite (and from basalt to rhyolite)." The crustal average for Mg reported by Taylor75is 2.33%. Weathering and Mobility. The most important Mg-minerals of igneous and metamorphic rocks which decompose during weathering are olivines, pyroxenes, amphiboles, biotites, and chlorites (the ferromagnesian minerals), and of sediments, dolomite, Mg-calcite, and chlorite. The ferromagnesian minerals are among the first to decompose during the process of rock weathering. Soil Contents. The total Mg content in 2723 soils from different parts of the world varies between 50 and 160 000 mg kg-' with a mean of 8262 mg kg-' (Table 5). For many soils, however, magnesium contents lie in the ranges of 0.2-0.8** or 0.04-0.9%74 Mg with a quoted median value of 0.5%.74Magnesium in soils exists in exchangeable, organically complexed, acid-soluble, and primary mineral forms. Most soil-Mg is in silicate minerals with relatively small amounts in the exchangeable and water-soluble forms. The Mg-containing silicate minerals include micas, micaceous clays, chlorites, vermiculites, and various ferromagnesian minerals, which are generally easily weathered and have a rather short life in soils. If not taken up by crops, labile Mg in the soil is vulnerable to leaching at a rate which depends upon the amount of soluble anions in the soil. Leached Mg may often accumulate in the subsoil. The combined losses by leaching and crop removal may be 1 1-55 kg Mg Some Mg, like K, may well be fixed in expanded 2 : 1 clays. Soils in temperate regions containing Mg-rich silicate minerals are, on average, higher in Mg than acid soils of the humid tropical regions. The relationship of Mg E. M. Romney and J. D. Childress, Soil Sci., 1965, 100, 210. R. J. B. Williams and H. H. Le Riche, Plant Soil, 1968.29,317. *'K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-1/12, Springer Verlag, Berlin. 82 R. C. Salmon, J . Sci. Food. Agric., 1963, 14, 605. l9

The Elemental Constituents ojSoils

103

Table 5 Magnesium soil contents (mg Mg kg-I) Soils Range 20 surface soils, New Jersey 240-1 1 670 18 soils, USA, 6 profiles 200-26 000 134 topsoils, S.W. Pacific 19 soils, USA, 4 profiles 960- 18 600 108 soils, Ghana, 19 profiles (300--3000 195 soils, California, 50 profiles 1200- I 6 0 000 5 surface soils, North Carolina 89-302 37 soils, Poland, 13 profiles 6000- 17 500 863 surface soils, USA 50-100 000 9 1 soils from 14 profiles 201-6602 10 surface soils, UK and Malaya 600-4700 2 10 surface and subsoils, Finland 2000-23 000 698 soils, New Zealand, 168 profiles 97-51 923 44 surface soils, N.W. India 10 944-19 699 5 1 surface soils, Denmark 185 soils, Canada, 54 profiles 300-45 000 23 soils, Scotland, 4 profiles 2000-20 000 12 topsoils, S.E. USA 180-24 600 2723 Soils Overall Mean 8262 mg Mg kg-l

Mean 5 144 5940 I I 400 8380 950 13 000 18Y 11 200 9200 2355 25 10 10 400 653 I 15 280 1420 8 200 10 780 4750

R eJ a

b 4 92 6 C

d e 77 83

50 52

1' '9 h 1

.i k

a A. L. Prince, M . Zimmerman, and F. E. Bear, Soil Sci.. 1947, 63, 69; J . Connor. N. Shrimp, and J . C. F. Tedrow, ibid.. 1957, 83, 383: G . R. Bradford, R. J. Arkley, P. F. Pratt, and F. L. Blair, Hilgardia, 1967, 38, 54 I ; H . B. Rice. and E. J . Kamprath, Soil Sci. Soc. Am. Proc.. 1968, 32, 386; 'B. Dobrazanski and J . Glinski, Rocz. Glebozn.. 1971, 21, 365; 'A. J. Metson, E. J . Gibson, and R. Lee, N . Z . Soil Bur. Sci. Rep.. No. 31, 100 pp.: P. K. Sharma, B. P. Kaistha. B. R. Tripathi. and R. D. Gupta. Agrochimica. 1977. 21. 529: J. C. Tjell and M. F. Hovmand, Acta Agric. Scand., 1978, 28. 81: ' J. A. McKeague. J. G. Desjardins. and M. S. Wolynetz. Agric. Canada. Ottawa 1979. LRRT Publ. 21: ' M . L. Berrow and R. L. Mitchell, Trans. R. Soc. Edinburgh: Earth Sci.. 1980, 71. 103: P. J. Lechler, W. R. Roy, and R. K. Leininger. SoilSci.. 1980. 130, 228

content to soil development and degree of weathering has been studied by Mokwunye and M e l ~ t e d . *The ~ silt and clay fractions in the soils chosen for this study contained more than 95% of the total soil Mg. Comparisons between temperate and tropical soils showed why highly weathered tropical soils are almost always deficient in Mg for plant growth. In a comprehensive study of Mg in New Zealand soils, the wide variations in total contents observed could be related to soil parent materials and degree of soil development as expressed in the genetic soil clas~ification.~~ Magnesium is essential to the growth of both plants and animals. It is an essential constituent of chlorophyll, but most of the Mg in plants is present in other forms. Magnesium is an activator of more enzymes than any other element; it is also involved in ion transport and cation balance in plants. Magnesium is also essential to the growth of humans and

Calcium.-Geochemistry. Calcium occurs in the upper continental crust of the earth to the extent of about 3.5% by weight and is fifth in the order of abundance

'' A. U. Mokwunye and S. W. Melstead. Cornmun. Soil Sci. Plan( Anal., 1973. 4. 397. 84

A. J. Metson and E. J . Gibson. N . Z . J . Agric. Res.. 1977. 20, 163.

'' J . B. Jones. jun., M. C . Blount, and S. R. Wilkinson, 'Magnesium in the Environment, Soils, Crops, Animals and Man'. Proc. Symp. Fort Valley. Georgia, USA. 1972. Fort Valley State College. 1972.

104

Env ironmen ta 1 Chemistry

(following 0, Si, Al, and Fe). It forms a large number of minerals, some of them being major constituents of rocks, including aluminosilicates, phosphates, carbonates, sulphates, and fluorides. Calcium aluminium silicate minerals formed at high temperatures, include plagioclase feldspars, pyroxenes, and amphiboles, while, of those formed at lower temperatures, calcite, aragonite, gypsum, dolomite, and high-Mg calcite are the most important. In sediments and sedimentary rocks Ca is mainly present in limestones or dolomites.86

Weathering and Mobility. The most important Ca-bearing minerals of igneous and metamorphic rocks that decompose during weathering are the plagioclases, pyroxenes, amphiboles, and epidote and in sedimentary rocks, calcite, dolomite, anhydrite, and gypsum. Experimental studies on the weathering of Ca silicates have produced solutions with a range of Ca concentrations, < 1-90, mean 15 mg kg-’, similar to those found in river waters. Surface sea water is normally saturated or nearly saturated with respect to CaCO, and a small amount of evaporation can cause precipitation.86 The geobiology of C a has been recently reviewed by Delwi~he.~~ Soil Contents. The mean total C a content in 1757 topsoil and soil profile samples from various parts of the world and derived from a wide range of parent materials is 1.96% with a range of 0.01-32% Ca (Table 6). The range of Ca contents in soils has been reported by B ~ w e n ’to~ be 0.07-50%, mean 1.5% Ca. Of those which are free of calcium carbonate, analyses have been reported showing values ranging from 0.086 to over 2%. Calcareous soil contents will vary from less than 1 to more than 25%. Extremely sandy soils in humid regions are frequently very low in total Ca content.88 Calcium occurs in soils ( a ) in primary mineral form, (b) as a constituent of inorganic compounds, (c) complexed or combined with organic matter, and (d) held by cation exchange. It is the major exchangeable cation in most soils and can be lost from soils by (i) leaching, (ii) crop uptake and removal, and (iii) erosion. In temperate humid conditions more Ca is lost by leaching than by cropping, and losses are replaced mainly by the application of lime. Calcium is a basic cation and thus neutralizes soil acidity. It also acts as a flocculator and this helps in maintaining the granular structure of soil particles.89 Lime is added to soils for several reasons which include (a) increasing the soil pH, (b) supplying Ca or C a and Mg, (c) obtaining optimum availability of nutrient cations, ( d ) increasing the availability of P and Mo, (e) increasing the rate of mineralization of nitrogen, and (f)reducing the activity of A1 ions in the soil to non-toxic levels. Calcium is essential to the growth of both plants and animals and plays a structural role as a constituent of cell walls in plants and as an essential component of the skeleton of many animals. The calcium ion is also involved in a number of metabolic processes. 8b

K. H. Wedepohl (ed.), ‘Handbook of Geochemistry’, 11-2/20., Springer Verlag, Berlin. C. C. Delwiche, Commun. Soil Sci. Plant Anal., 1975, 6, 207. H. D. Chapman, ‘Diagnostic Criteria for Plants and Soils’, Univ. of California, Div. of Agric. Sci., 1966.

89

R. 0. McLean, Commun. Soil Sci. Plant Anal., 1975,6, 219.


105

Table 6 Calcium soil contents (% Ca) Mean Ref: Soils Range 4 1.32 134 topsoils, S.W. Pacific 92 0.983 trace-3.99 19 soils, USA, 4 profiles 0.46 0.107- 1.21 6 108 soils, Ghana, 19 profiles 7 139 soils Quebec, B horizons 3.69 77 2.40 863 surface soils, USA (0.0 15-3 2 0.327 50 0.01-0.96 10 surface soils, UK and Malaya 52 1.08 0.28-1.9 2 10 surface and subsoils, Finland a 1.39-16.65 5.65 4 soils, Canada b 0.347 5 1 surface soils, Denmark C 1.50 184 soils, Canada, 54 profiles 0.03-1 3.1 d 2.22 23 soils, Scotland, 4 profiles 1.O-4.6 e 1.72 0.02 1-1 3.29 12 topsoils 1757 Soils Overall Mean 1.96% C a “ R . D. Koons and P. A. Helmke, Soil Sci. SOC.A m . J., 1978, 42, 237; ‘ J . C. Tjell and M. F. Hovmand, Acta Agric. Scand., 1978, 28, 81; J . A. McKeague, J. G. Desjardins, and M. S. Wolynetz, Agric. Canada, Ottawa 1979. LRRI Publ. 21: M. L. Berrow and R. L. Mitchell. Trans. R. SOC.Edinburgh: Earth Sci., 1980, 71, 103; P. J . Lechler, W. R. Roy, and R. K. Leininger, Soil Sci., 1980, 130,238

Strontium.-Geochemistry. The bulk of the Sr in the earth’s crust occurs as a trace element dispersed in rock-forming and accessory minerals. The distribution of Sr(Sr2+, 1.13 A) in rock-forming minerals is controlled by its diadochy with Ca(Ca2+, 0.99 A) and K (K+, 1.33 A), and it commonly occurs in plagioclases and K-feldspars. The Sr levels found in other rock-forming minerals are considerably lower than those in the feldspars and are particularly low in micas. Among sedimentary rocks, limestones often contain high levels of Sr, up to 11 000 mg kg-’, whereas sandstones generally only contain 40-1 50 mg kg-’ and greywackes 100-400 mg Sr kg-’.90 The chief minerals of Sr are the sulphate and the carbonate and these occur as molecular deposits in sedimentary rocks or as veins possibly of hydrothermal origin. The crustal average Sr content is 375 mg kg-1.75 Weathering and Mobility. Losses of Sr during the weathering of rocks have been reported by Butler,” Short,92 and Rice,’* all indicating that Sr is a rather mobile element during rock weathering, particularly under conditions where decomposition of feldspars occurs. About 80% of the Sr in the rivers of the world is derived from the weathering of carbonates and sulphates, the remaining 20% being from silicates. Thus the major rock type involved in the Sr cycle is limestone.

Soil Contents. The range of Sr contents in topsoils and soil profile samples from various parts of the world and derived from a wide range of parent materials is 6000 1100-15 000 360 soils, China, 11 1 profiles 600-13 900 108 soils, Ghana, 19 profiles 139 soils, Quebec, B horizons 3300-16 500 34 soils, Galapagos, 13 profiles 1800-9900 6 1 soils, Burma, 17 profiles 650-34 000 1 13 soils, Madagascar, 26 profiles 1460-6 3 20 29 soils, Portugal, 6 profiles 300-15 000 863 topsoils, USA 12 soils, Scotland (60-16 400 19 1 soils, Canada, 8 1 profiles 400- 18 000 10 topsoils, Scotland 1900- 15 000 23 soils, Scotland, 4 profiles 2000-26 000 2 160-8270 12 topsoils, S.E. USA Overall Mean 509 1 mg Ti kg-' 2192 Soils

Mean 4 200 4 700 8085 72 10 4860

>4450 6500 3830 10 500 9350 43 10 7470 3004 3000 4730 4400 6400 10 960 4360

R ex 228 a 3 4 92 5 b 6 7 9 21 22 C

77 108

d 69

e

f

a A. L. Prince, Soil Sci., 1957, 84, 413; C. L. Fang, T. C. Sung, and Bing Yeh, Acta Pedologica Sinica, 1963, 11, 130; A. S. Coutinho, A. J. Das Texieira, E. M. De Sequeira, and M. D. Lucas, Agron. Lusit., 1973, 33, 257; J. A. McKeague, J. G . Desjardins, and M. S. Wolynetz, Agric. Canada, Ottawa, 1979, L R R l Publ. 21; e M . L. Berrow and R. L. Mitchell, Trans. R . SOC.Edinburgh: Earth Sci., 1980, 71, 103;fP. J. Lechler, W. R.Roy, and R.K. Leininger, Soil Sci., 1980, 130,238

soil, derived from chlorite schist, contained 7% Ti, almost entirely in the form of cryptocrystalline anatase. The A horizons of Scottish podzols often contain unusually large amounts (up to 140 mg kg-') of Ti extractable by edta. This form of Ti appears to be derived from the dissolution of Ti-minerals followed by Titanium has been found to be reprecipitation in situ in secondary form.108*109 subject to mobilization in four Canadian soils, thus making it unreliable as a weathering index."O Organic acids in soils may be involved in the mobilization of Ti as has been shown by Dumon.lll

Soil Contents. The mean Ti contents of 2192 soils on a world wide basis is calculated to be 5091 mg kg-' as shown in Table 9 with a range of 1000 134 topsoils, S.W. Pacific 19 soils, USA, 4 profiles 48-1 170 82 soils, Australia, 12 profiles 50-1 180 109 soils, Ghana, 19 profiles 20-2000 139 soils, Quebec, B horizons 34 soils, Galapagos, 13 profiles 62-540 1 13 soils, Madagascar, 26 profiles 20-1850 863 topsoils, USA < 10-2000 110 soils, Cameroon, 18 profiles 470-1054 26 I topsoils, Wales 60-970 227 subsoils, Wales 73-468 10 topsoils, Scotland 230- 1000 23 soils, Scotland, 4 profiles 20-400 Overall Mean 345 mg Zr k g - ' 2299 Soils

Mean 239 632 496 5 I6 263 275 960 227 363 240 676 265 28 5 604 208

R eJ:

a 3 4 92 1 I6 6 7 9 22 77 23 h h 69 122

" J . Lounamaa, Ann. Bot. SOC.Vunumo, 1956. 29; I, R. 1. Bradley, C . C. Rudeforth, and C . Wilkins, J . Soil. Sci., 1978, 29, 258.

K. H. Wedepohl (ed.), 'Handbook of Geochemistry', 11-4/40. Springer Verlag, Berlin. R. R. Brooks. 'Geobotany and Biogeochemistry in Mineral Exploration'. Harper and Row, New York, 1972. ' I 5 V. M. Goldschmidt, 'Geochemistry', ed. A. Muir. Clarendon Press, Oxford, 1954. ' I 6 A. Wild. A us[. J . Agric. Res.. 196 1. 12. 300. 'I3

'I4

111


Soil Contents. The mean content of Zr in 2299 soils sampled world-wide was calculated (Table 10) to be 345 mg kg-' with a range of < 10-3000 mg kg-I. Other estimates of the abundance of Zr in the soils of the world by various authors have been summarized by W e d e p ~ h l . "A ~ typical range is 50-2000 mg kg-' with a mean of 300 mg kg-I. The range of Zr contents of 3 179 soil samples from the United States has been given at basalts > andesites > granites and rhyolites. Contents of Ni in rocks are often correlated with those of Mg, Co, or Cr.274The crustal average for Ni has been reported to be 75 mg kg -'with averages for basalt of 150 mg kg-' and for granite of 0.5 mg kg-'.75

Weathering and Mobility. Nickel is relatively easily mobilized during weathering because it is contained in the more easily weathered ferromagnesian minerals. It is, however, coprecipitated with iron and manganese oxides. In tropical climates, where ultrabasic rocks rich in Ni are weathered, a residual Ni-rich lateritic soil develops which is of economic importance. The common Ni-mineral associated with these deposits is garnierite which is now the source of about half the total annual Ni production. Nickel, together with other metals, is also concentrated in marine manganese nodules.274 Soil Contents. The total nickel contents of 4625 samples of soil detailed in Table 20 range from 0.1-1523 mg kg-' with a mean of 33.7 mg kg-'. Soil nickel Table 20 Nickel soil contents (mg Ni kg-') Soils 100 topsoils, Finland 18 soils, USA, 6 profiles 36 soils, Scotland, 7 profiles 129 topsoils, S.W. Pacific 19 soils, USA, 4 profiles 375 topsoils, Finland 360 soils, China, 11 1 profiles 108 soils, Ghana, 19 profiles 68 soils, Spain, 23 profiles 19 soils, Germany, 4 profiles 195 soils, California, USA, 50 profiles 34 soils, Galapagos, 13 profiles 34 soils, Poland, 9 profiles 210 topsoils, Burma 68 soils. Burma, 17 profiles 113 soils, Madagascar, 26 profiles 64 soils, Poland, 22 profiles 863 topsoils, USA 110 soils, Cameroon, 18 profiles 27 soils, Japan, 7 profiles 39 topsoils, Canada 293 topsoils, Ontario 46 soils, Poland, 9 profiles 36 1 topsoils, Sweden 260 topsoils, Wales 230 subsoils, Wales 66 soils, USSR, 18 profiles 5 1 topsoils, Denmark 752 topsoils, England and Wales 274

Range

< 10-300 2-77 4- I50 -

5-27 13-46 11-180 < 10-200 3.2-957 20-300 4.2- 1 5 23 20-270 16-35 -

12-93 3-530 12-92 0.5-7 mg kg-I) than silt fractions (0.5-2 mg kg-1).380

Soil Contents. A bibliography of references to silver in plants and soils has been published381and a few early workers have reported the contents of silver in soils. mg Ag kg-I, and L o ~ n a m a a ~reports ~* S ~ a i n egives ~ ~ a range of 10.0 1.15-1 1.60 7.2- 10.0 0.1-1 1.5 4 .O-7.6 4.1-9.6 0.79- 14.55

Mean 6.40 9.03 7.77 8.16 5.03 5.62 6.60 4.37 8.78 6.2 5.69 7.44 7.75

R eJ 228 4 92 6 a

b 77 C

d

e 69 122 805

1770 Soils Overall Mean 6.65% AI ' G. R. Bradford. R. J. Arklev. P. F. Pratt. and F. L. Blair. Hikardia., 1967, 38, 541; ' B . Dobrianski and J. Glinski. Rocz. Glehozn., 1971. 21, 365: ' A. S. Coutinho. A. J . Das Texiera, E. M. De Sequeira. and M. D. Lucas. Agron. Lusif., 1973. 33, 257; " L . F. Molloy and L. C. Blakemore, N . Z . J. Sci.. 1974, 17, 233; ('J. A. McKeague, J . G . Desjardins, and M. S. Wolynetz. Agric. Canada, Ottawa 1979. LRRI Publ. 2 1

50R 5n9

K. H. Wedepohl (ed.). 'Handbook of Geochemistry'. 11- 1 /13. Springer Verlag, Berlin. E. 0. McLean, Cornrnun. Soil Sci. Plan1 Anal.. 1976. 7. 6 19.


159

co-ordination with six OH, groups from each of which a hydrogen ion dissociates sequentially as the pH increases. The resulting hydroxo-A1 ions are adsorbed onto the cation-exchange system of the soil where they can obstruct the exchange of cations. Mobile A1 also reacts readily with soluble phosphates converting them to relatively insoluble and unavailable forms. The acidic nature of adsorbed and polymerized Al can lead to a misinterpretation of the true lime requirement of soil. In addition it can also affect the apparent requirement by its effect on the buffers used in the lime-requirement test. The level of exchangeable Al may therefore be an adequate index of lime requirement on highly weathered soils.5o9 During the podzolization process A1 and Fe move down the soil profile, being removed from the eluvial A horizons to be deposited in the illuvial horizons of accumulation, the B horizons. It has been commonly argued that the formation of podzols involves the transport of Al and Fe as organic c o r n p l e x e ~ but , ~ ~recent ~ ~ ~ evidence ~~ for the presence of imogolite and proto-imogolite allophane in podzol B horizons suggests that A1 moves in the form of a mobile ahminosilicate complex.512 The natural occurrence of allophane and imogolite in a soil environment has been recently reviewed.513The origin, composition, and structure of the oxides of aluminium, iron, and manganese in clays has been reviewed by Mackenzie et al.,514and the occurrence of amorphous materials of aluminium, iron, and silica in soils has been reviewed by Mitchell et al.515The formation of aluminium oxyhydroxides in soils has been recently reviewed by H s u . ~ ' ~ The Al-hydroxide layers in clay minerals and individual crystals, or in polymerized particles of gibbsite, contain positively charged adsorption sites which may play important roles in soils as points where anionic nutrient species (e.g., nitrate or borate) can be retained for later extraction by plant roots. Although the essentiality of Al for plant or animal growth has not been proved, A1 in soil is of great importance in the growth of plants. Soluble A1 is toxic to most plants and problems of toxicity can occur in acid soils. Some plant species accumulate Al, however, and Al succinate has been found to be exuded in the acid sap of some accumulator plants.s08It has also been found that bryophytes (mosses) contain a higher percentage of Al in their ashes than is common in the higher plant forms. These primitive plants play a significant role in weathering and in the development of soil on exposed rock surface^.^'^,^^'

Gallium.-Geochemistr. Although Ga is widespread in nature, its minerals are extremely rare and this element is generally associated with Al in the common minerals. The main feature of the distribution of G a in igneous rocks is its rather McKeague, G . J. Ross, and D. S. Gamble, in 'Quaternary Soils: 3rd Conf. on Quaternary Research'. ed. W. C. Mahaney, Geo. Abstracts Ltd., Norwich, 1978. p. 27. "' E. W. Russell, 'Soil Conditions and Plant Growth'. 10th Edn., Longman. London, 1973. 'I2 V . C. Farmer, J . D. Russell. and M. L. Berrow. J . Soil Sci.. 1980. 31. 673. ' I 3 K . Wada, in 'Minerals in Soil Environments', ed. J . B. Dixon, and S. B. Weed. Soil Sci. Soc. Am., Madison, Wisc., USA, 1977, p. 603. 'I4 R. C. Mackenzie, E. A. C. Follett, and R. Meldau. in 'The Electron optical Investigation of Clays', ed. J . A. Gard, Min. Soc. Monogr. No. 3, 197 1, p. 3 15. B. D. Mitchell. V. C. Farmer, and W. J . McHardy, A h . Agron., 1964, 16, 327. 5 ' 6 P. H. Hsu, in 'Minerals in Soil Environments', ed. J . B. Dixon and S. B. Weed. Soil Sci. SOC.Am., Madison, Wisc.. USA, 1977, p. 99. 5 ' 7 D. Jones, M. J. Wilson. and J . M. Tait, Lichenologisl. 1980, 12. 277.

s'" J . A.

En u iron men ta 1 Chemistry

160

uniform occurrence in most basic, intermediate, and granitic rocks. This is related to the role of feldspars as the main carriers of G a in these rocks. A\ :Ga ratios vary from 2500 to 50 000 in rocks with a mean of about 5000. The average concentration of G a in basalts is 17 mg kg-' and in granites to 18.5 mg kg-', these values being consistent with a figure of 18 mg kg-', which appears to be the best estimate of the crustal abundance of Ga.518Gallium levels are generally higher in freshwater than in marine argillaceous deposits. The low levels of G a in sandstones accord with the known depletion of the element in quartz. A crustal average content for gallium of 15 mg kg-' has been reported by Taylor.75

Weathering and Mobility. Gallium, like Al, is enriched in the products of intense weathering; it is more mobile than Al, however, and the ratio A1:Ga commonly increases in the residual materials in the weathering process. The element exists as Ga3+ in natural environments and the most important factor affecting its behaviour in the cycle of weathering and sedimentation is the low solubility of the hydroxide. Gallium is therefore not readily transported by most natural waters. Soil Contents. The mean gallium content in 1615 soils sampled world-wide was mg G a calculated (Table 28) to be 21.1 mg kg-' with a range of about 2-200 kg-'. This is in good agreement with the data of B ~ w e n , a' ~median value of 20 mg G a kg-' and a range of 1-200 mg G a kg-'. Gallium is present in most soils where it occurs mainly in aluminosilicates, isomorphously replacing A1 in the structure, and many soils thus have total A1:Ga ratios of -5000-10000. The general tendency for G a to be concentrated in residual materials, even though generally to a lesser degree than Al, is reflected in the fact that in many soil profiles the concentration of G a is positively correlated with the amount of clay. The usual trend in soil profiles is for a slight increase in G a content with increase in depth.518 There is little variation in the Ga content in soils from different climatic zones:

Table 28 Gallium soil contents (mg G a kg-') Soils Range 134 topsoils, Finland 3.5 nmol kg-' in near-bottom waters. In the East Pacific Ocean at 33ON, surface waters contained 1.5 nmol kg-' and deeper waters 0.55 nmol kg-', but there was an increase to about 1.5 nmol kg-' in the dioxygen minimum region, which here contained only some 10 p m o l 0 , kg-I. Some earlier measurements of dissolved manganese in the Atlantic Ocean had indicated comparable concentrations to those found for TDM by Bender et a1.88 Thus concentrations of 0.5-1.6 nmol I-' were found in surface waters collected off the shelf west of Scotland.89A geometric mean concentration of 1.5 nmol I-' has been given70 for Atlantic Slope water off Nova Scotia; concentrations in Central Atlantic water in the same region were below 0.75 nmol I-'. Klinkhammer and Benderg0 reported vertical distributions of TDM for 13 stations in the Pacific Ocean. Concentrations of particulate manganese ranged from 5-50% of those of TDM and the trends in the two quantities were not generally related except in some bottom waters. Profiles in the Northern Hemisphere typically showed surface maxima of 1-3 nmol kg-I, concentrations decreasing below the mixed layer to about 1 nmol kg-I. In the dioxygen minimum zone increases in concentration of TDM, up to 3.9 nmol kg-I at one station, were often found, and below this zone, concentrations decreased to about 0.5 nmol kg-'. At some stations, increases in concentration occurred near the sea-bed. Profiles in the South Pacific Ocean mostly showed surface maxima but with concentrations (

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