Table Of ContentISSUES IN ENVIRONMENTAL SCIENCE
AND TECHNOLOGY
EDITORS: R. E. HESTER AND R. M. HARRISON
6
Chlorinated
Organic
Micropollutants
ISBN 0-85404-225-3
ISSN 1350-7583
A catalogue record for this book is available from the British Library
@ The Royal Society of Chemistry 1996
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Editors
Ronald E. Hester, BSc, DSc(London), PhD(Cornell), FRSC, CChem
Ronald E. Rester is Professor of Chemistry in the University of York. He was for
short periods a research fellow in Cambridge and an assistant professor at Cornell
before being appointed to a lectureship in chemistry in Y orkin 1965. Hehas been a
full professor in York since 1983. His more than 300 publications are mainly in the
area of vibrational spectroscopy, latterly focusing on time-resolved studies of
photoreaction intermediates and on biomolecular systems in solution. He is active
in environmental chemistry and is a founder member and former chairman of the
Environment Group of The Royal Society of Chemistry and editor of 'Industry
and the Environment in Perspective' (RSC, 1983) and 'Understanding Our
Environment' (RSC, 1986). As a member of the Council of the UK Science and
Engineering Research Council and several of its sub-committees, panels and
boards, hehas been heavily involved in national science policy and administration.
He was, from 1991-93, a member of the UK Department of the Environment
Advisory Committee on Hazardous Substances and is currently a member of the
Publications and Information Board of The Royal Society of Chemistry.
Roy M. Harrison, BSc, PhD, DSc (Birmingham), FRSC, CChem, FRMetS, FRSH
Roy M. Harrison is Queen Elizabeth II Birmingham Centenary Professor of
Environmental Health in the University of Birmingham. He was previously
Lecturer in Environmental Sciences at the University of Lancaster and Reader
and Director of the Institute of Aerosol Science at the University of Essex. His
more than 250 publications are mainly in the field of environmental chemistry,
although his current work includes studies of human health impacts of
atmospheric pollutants as well as research into the chemistry of pollution
phenomena. He is a former member and past Chairman of the Environment
Group of The Royal Society of Chemistry for whom he has edited 'Pollution:
Causes, Effects and Control' (RSC, 1983;T hird Edition, 1996) and 'Understanding
our Environment: An Introduction to Environmental Chemistry and Pollution'
(RSC, Second Edition, 1992). He has a close interest in scientific and policy aspects
of air pollution, currently being Chairman of the Department of Environment
Quality of Urban Air Review Group as well as a member of the DoE Expert Panel
on Air Quality Standards and Photochemical Oxidants Review Group and the
Department of Health Committee on the Medical Effects of Air Pollutants.
XI
Contributors
R. Atkinson, University of California, Statewide Air Pollution Research Center,
Riverside, CA 92521, USA
P. Cains, Environmental and Process Engineering, AEA Technology, 404 H arwell,
Didcot, Oxon OX]] ORA, UK
P. de Voogt, Amsterdam Research Institute for Substances in Ecosystems,
Department of Environmental and Toxicological Chemistry, University of Amsterdam,
Nieuwe Achtergracht 166,1018 WV Amsterdam, Netherlands
G. H. Eduljee, Environmental Resources Management, Eaton House, Wallbrook
Court, North Hinksey Lane, Oxford OX2 OQS, UK
s. J. Harrad, School of Chemistry, Institute of Public and Environmental Health,
The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
M. McLachlan, Ecological Chemistry and Geochemistry, University of Bayreuth,
D-95400 Bayreuth, Germany
A. G. Nixon, University of Tennessee, Knoxville, TN 37996, USA
S. Safe, Department of Veterinary Physiology and Pharmacology, Texas A & M
University, College Station, TX 77843-4466, USA
D. L. Swackhamer, Environmental and Occupational Health, School of Public
Health, Box 807 UMHC, 420 Delaware St SE, University of Minnesota,
Minneapolis, MN 55455, USA
c. c. Travis, Health Sciences Research Division, Oak Ridge National Laboratory
1060 Commerce Park Drive, Oak Ridge, TN 37830, USA
A. B. TurnbulI, School of Chemistry, Institute of Environmental and Public H ealth,
The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
XII
Preface
In this volume of Issues we address the sources, environmental cycles, uptake,
consequences and control of many of the more important chlorinated organic
micropollutants. Under this heading we have included a range of semi-volatile
persistent compounds, notably polychlorinated biphenyls (PCBs), polychlorinated
dibenzo-p-dioxins(PCDDs) and polychlorinated dibenzofurans (PCDFs) as well
as a number of chlorinated pesticides. We have not sought to include volatile
speciess uch as CFCs which cause environmental problems of an entirely different
nature. The compounds included in this volume cause no threat to the
stratospheric ozone layer, but have given widespread cause for concern in
relation to their environmental persistence and high toxicity, and their potential
for adverse effects on humans and wildlife.
Despite the fact that PCBs and some of the chlorinated pesticides are no longer
manufactured, they remain relatively abundant in the environment because of
their low reactivity. A further consequence of this chemical inertness and their
lipid solubility is a tendency to concentrate within food chains and hence present
the greatest level of risk to those at the top of the food chain. In the case of PCD Ds
and PCDFs, there is evidence of natural production from sources such as forest
fires, but this appears to be modest in magnitude, and current environmental
burdens result largely from human activity. Prior to the Seveso incident few had
heard of these compounds, whereas nowadays 'dioxins' are regarded as major
environmental hazards by the general public, who derive their opinions largely
from poorly informed press coverage, itself often fuelled by incomplete and
sometimes inaccurate information put forward by pressure groups, but reflecting
also some genuine disagreements within the scientific community over the risks
posed by these compounds.
Rational decision making over chlorinated organic micropollutants in the
environment must be based upon sound science. This volume draws upon the
expertise of some of the most distinguished workers in this field to review current
knowledge of the sources, environmental concentrations and pathways, human
toxicity and ecotoxicology, and control methods for these groups of compounds.
In the first article, Harrad addresses some of the problems of quantification
inherent in understanding the environmental inventories and budgets of PCBs,
PCDDs and PCDFs. The source inventory approach is extended by Travis and
Nixon in the second article to evaluate sources of human exposures to PCDDs
Preface
and PCDFs. Such exposure to these compounds depends crucially upon
biological uptake and transfers through the food chain, for example, from
atmospheric emissions into pasture grass and thus into cows' milk; McLachlan
provides a detailed insight into the processes involved and their relative
efficiencies. Despite their known persistence in the environment, PCBs, dioxins
and furans are both decomposed within, and removed from, the atmosphere by
scavenging processes,a nd Atkinson reviews knowledge of the processes involved.
The next two articles by Safe and de Voogt describe, respectively, the human
toxicology and ecotoxicology of exposure to chlorinated organic micropollutants.
These put into clear context the consequences of the exposures estimated through
the early chapters. Turnbull then focuses on the usage, environmental cycles and
concentrations of chlorinated pesticides, showing that even compounds which
are subject to extensive bans upon production and use are still cycling within the
environment. One of the ecosystems which has suffered the greatest pollution
from PCBs is the North American Great Lakes system. This has been the subject
of intensive scientific investigation which is described as a case study by
Swackhamer. Historically, one of the most important source categories for
'dioxin' emissions has been the combustion of waste in incinerators. Since the
'dioxin' problem became evident, far more stringent controls have been applied in
developed countries to incinerator emissions and much has been learnt about the
optimal techniques for controlling PCDD and PCDF formation and emission. In
the final article, Eduljee and Cains describe the operating procedures and control
technologies available for minimizing such emissions.
We believe that this volume gives a unique and valuable compilation of
information on an extremely important group of environmental pollutants. It is
fully up-to-date and should provide a comprehensive overview of this topical
subject useful for some years to come.
Ronald Eo Rester
Roy Mo Harrison
VI
Contents
Sources and Fates of PolychlorinatedDibenzo-p-dioxins,
Dibenzofuransand Biphenyls: The Budget and Source Inventory Approach 1
Stuart J. Harrad
1 Introduction 1
2 PhysicochemicalProperties and Environmental Levels 2
3 Environmental Budgets 2
4 Source Inventories 9
5 Conclusions 15
Human Exposure to Dioxin 17
Curtis C. Travis and April G. Nixon
1 Introduction 17
2 Measuring Toxicity Levels 17
3 EnvironmentalConcentrations Reveal Ubiquity of Dioxin 18
4 Sources of Dioxin 18
5 Accumulationof PCDD/Fs in the Food Chain 24
6 Comparing Source Emissions to Deposition Estimates 27
7 Human Exposures to PCDDs and PCDFs 28
8 Conclusions 30
Biological Uptake and Transfer of Polychlorinated
Dibenzo-p-dioxins and Dibenzofurans 31
Michael S. McLachlan
1 Introduction 31
2 Soil/Plant Transfer 32
3 Atmosphere/Plant Transfer 36
4 Transfer from Plants to Livestock and Animal Food 44
5 Transfer from Food to Humans 50
6 Transfer from Human Milk to Infants 51
vii
Contents
7 Concluding Remarks 51
8 Acknowledgements 52
Atmospheric Chemistry of PCBs, PCDDs and PCDFs 53
Roger Atkinson
1 Introduction
2 Gas/Particle Partitioningof PCBs, PCDDs and PCDFs in the
Atmosphere 55
3 Physical Removal Processes 56
4 Chemical Transformations 59
5 Transformationsof Gas-phase PCBs, PCDDs and PCDFs 61
6 Transformations of Particle-phase PCBs, PCDDs and PCDFs 69
7 Tropospheric Lifetimes of PCBs, PCDDs and PCDFs 70
8 Conclusions 72
9 Acknowledgements 72
Human Toxicology of Chlorinated Organic Micropollutants 73
Stephen Safe
1 Introduction 73
2 Human Toxicology of Organochlorine Pollutants 75
3 PCDDs/PCDFs 76
4 PCBs 81
5 Halogenated Aromatics and the Endocrine Disruption Hypothesis 87
6 Acknowledgements 88
Ecotoxicology of Chlorinated Aromatic Hydrocarbons 89
Pim de Voogt
1 Introduction 89
2 Bioaccumulationof CACs 91
3 Biotransformation 98
4 E⁄ects 106
5 Conclusions 111
6 Acknowledgements 112
Chlorinated Pesticides 113
Alan Turnbull
1 Introduction 113
2 A Brief History of the OrganochlorinePesticides 113
3 OrganochlorinePesticide Production, Use and Regulation 115
4 Partitioning in the Environment 118
5 Environmental Occurrence 125
6 EnvironmentalToxicity 132
7 Conclusions 135
viii
Contents
Studies of Polychlorinated Biphenyls in the Great Lakes 137
Deborah L. Swackhamer
1 Introduction 137
2 PCB Concentrations in the Great Lakes 139
3 PCB Fate and Transport 143
4 Bioaccumulation and Foodweb Dynamics 150
5 Summary and Conclusions 153
6 Acknowledgements 153
Control of PCDD and PCDF Emissions from Waste Combustors 155
Gev H. Eduljee and Peter Cains
1 Introduction 155
2 Early Investigations 156
3 US and Canadian Studies 157
4 Implementationof Good Combustion Practice 161
5 Reaction Fundamentals and Control Strategies 169
6 Summary 176
7 Acknowledgements 179
Subject Index 181
ix
Sources and Fates of Polychlorinated
Dibenzo-p-dioxins, Dibenzofurans and
Biphenyls: The Budget and Source
Inventory Approach
STUART J. HARRAD
1 Introduction
Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans
(PCDFs) and polychlorinated biphenyls (PCBs) have attracted considerable
attentioninrecentdecades,owingtoconcernovertheirpotentialadversee⁄ects
inhumansandwildlife,whicharecompoundedbytheirubiquitousenvironmental
presence and resistance to degradation.Amongst the 75 possible PCDDs, 135
PCDFsand209PCBs,thereexistswidevariationinphysicochemicalproperties,
bioaccumulative tendencies and toxicity. Figures 1 and 2 illustrate the basic
structuresandnomenclatureofbothPCDDs,PCDFs—collectivelyreferredtoas
PCDD/Fs—and PCBs.
This chapter reviews our knowledge of several key issues pertaining to the
environmentalpresenceofthesecompounds.Constructingsourceinventoriesfor
Figure1Basicstructures
andnomenclatureof
PCDD/Fs
1
