Fate of Pesticides in the Atmosphere: Implications for Environmental Risk Assessment: Proceedings of a workshop organised by The Health Council of the Netherlands, held in Driebergen, The Netherlands, April 22–24, 1998

274 Pages·1999·30.6 MB·English

by  H. F. G. van Dijk

FATE OF PESTICIDES IN THE ATMOSPHERE:
IMPLICATIONS FOR
ENVIRONMENTAL RISK ASSESSMENT
Fate of Pesticides in the Atmosphere:
Implications for
Environmental Risk Assessment
Proceedings of a workshop organised by
The Health Council of the Netherlands,
held in Driebergen, The Netherlands,
Apri/22-24, 1998
Edited by
HARRIE F.G. VAN DIJK
Health Council of the Netherlands,
The Hague, The Netherlands
W. ADDOJ. VAN PUL
National Institute of Public Health and the Environment (RIVM),
Bilthoven, The Netherlands
PIMDEVOOGT
University of Amsterdam
Amsterdam, The Netherlands
GEZONDHEIDSRAAD
Reprinted from Water, Air, and Soil Pollution 115: 1-4, 1999
SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.
A C.I.P. Catalogue record for this book is available from the Library of Congress.
ISBN 978-90-481-5329-9 ISBN 978-94-017-1536-2 (eBook)
DOI 10.1007/978-94-017-1536-2
Printed on acid-free paper
All rights reserved
© 1999 Springer Science+B usiness Media Dordrecht
Originally published by Kluwer Academic Publishers in 1999
Softcover reprint of the hardcover I st edition 1999
No part of the material protected by this copyright notice may be reproduced
or utilized in any form or by any means, electronic or mechanical,
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TABLE OF CONTENTS
H.F.G. VAN DIJK, W.A.J. VAN PUL and P. DE VOOGT I Atmospheric Transport of Pesti
cides: Assessing Environmental Risks
R. GUICHERIT, D.J. BAKKER, P. DE VOOGT, F. VAN DEN BERG, H.F.G. VAN DIJK
and W.A.J. VAN PUL I Environmental Risk Assessment for Pesticides in the
Atmosphere; The Results of an International Workshop 5-19
H.F.G. VAN DIJK and R. GUICHERIT I Atmospheric Dispersion of Current-Use Pesticides:
A Review of the Evidence from Monitoring Studies 21-70
N.M. VAN STRAALEN and C.A.M. VAN GESTEL I Ecotoxicological Risk Assessment of
Pesticides Subject to Long-Range Transport 71-81
M.S. MAJEWSKI I Micrometeorologic Methods for Measuring the Post-Application
Volatilization of Pesticides 83-113
T.F. BIDLEMAN I Atmospheric Transport and Air-Surface Exchange of Pesticides 115-166
J.A. VAN JAARSVELD and W.A.J. VAN PUL I Modelling of Atmospheric Transport and
Deposition of Pesticides 167-182
A.J. GILBERT I Regulatory Risk Assessment of Pesticide Residues in Air 183-194
F. VAN DEN BERG, R. KUBIAK, W.G. BENJEY, M.S. MAJEWSKI, S.R. YATES, G.L.
REEVES, J.H. SMELT and A.M.A. VANDER LINDEN I Emission of Pesticides
into the Air 195-218
R. ATKINSON, R. GUICHERIT, A.A. HITES, W.-U. PALM, J.N. SEIBER and P. DE VOOGT
I Transformations of Pesticides in the Atmosphere: A State of the Art 219-243
W.A.J. VAN PUL, T.F. BIDLEMAN, E. BRORSTROM-LUNDEN, P.J.H. BUILT JES, S.
DUTCHAK, J.H. DUYZER, S.-E. GRYNING, K.C. JONES, H.F.G. VAN DIJK and
J.A. VAN JAARSVELD I Atmospheric Transport and Deposition of Pesticides: An
Assessment of Current Knowledge 245-256
D.J. BAKKER, A.J. GILBERT, D. GOTTSCHILD, T. KUCHNICKI, R.W.P.M. LAANE, J.B.H.J.
LINDERS, D. VAN DE MEENT, M.H.M.M. MONTFORTS, J. PINO, J.W. POL
and N.M. VAN STRAALEN I Implementing Atmospheric Fate in Regulatory Risk
Assessment of Pesticides: (How) Can it be Done? 257-266
List of Participants 267-272
The Organising Committee 273
About the Health Council of the Netherlands 275-276
ATMOSPHERIC TRANSPORT OF PESTICIDES: ASSESSING
ENVIRONMENTAL RISKS
Current global food requirements have made great demands on agricultural
production, including the need for efficient weed and pest control. In the
second half of the 20th century, this had led to an ever increasing use of
pesticides. Pesticides are a special case inasmuch as they are applied directly in
the environment for the purpose of eliminating pests. Due to their obvious
inherent toxicity, strict regulations exist throughout the world regarding their
registration.
However, that non-target areas, even in remote places, can be exposed to
chemicals that have become airborne elsewhere and that this exposure can
cause unwanted effects, has only come to light in the last two decades. The
global atmospheric transport of 'common' gaseous pollutants like sulphur
dioxide and freons was already known at that time. Yet it was the observation
of the presence of organochlorine pesticides (such as lindane and toxaphene)
and industrial chemicals (like the polychlorinated biphenyls) in for example,
animals living in the Arctic, which spurred serious scientific and political
interest in the long-range transport of substances. Surprisingly, the monitoring
efforts made in remote areas as a result of this awareness, have shown that
compounds (perhaps) initially believed to be degraded quite rapidly after
application, may still be found far away from the application area.
International bodies and governmental agencies, such as the UNEP and
the UN-ECE, have launched activities to tackle the issue of the long-range
transport of chemicals. Most of these initiatives focus on the so called
persistent organic pollutants (POPs) or persistent, bio-accumulating and toxic
(PBT) substances. This raises the obvious question of definitions. The issue of
how to incorporate a chemical's potential for being transported over long
distances, into the regulations for registration, of both industrial chemicals and
modem pesticides, is an issue which has received relatively little attention to
date. For pesticides, this is all the more surprising when one considers their
typical use, where a relatively high potential for becoming airborne is obvious.
The Health Council of The Netherlands took the initiative to organise a
workshop on the issue of'Fate of pesticides in the atmosphere; implications for
risk assessment'. About forty experts were invited to discuss this subject with
the aims of reviewing the current scientific knowledge and possible risk
assessment approaches and exploring possible statutory, environmental criteria
that could be incorporated into pesticide regulation.
This special issue of Water, Air and Soil Pollution publishes the
proceedings of the workshop held in Driebergen, The Netherlands on April
22-24, 1998. First, an extended summary of the deliberations of the workshop
is presented followed by keynote papers that were presented during it. Finally
discussion papers summarise the several topics discussed. Contributions were
Water, Air, and Soil Pollution 115: 3-4, 1999.
© 1999 Kluwer Academic Publishers.
4 H.F.G. VAN DUK
received from invited keynote speakers, or drafted from the minutes taken and
audio recordings made during the discussions. All contributions were subjected
to the usual peer review procedure of WASP.
The editors wish to express their gratitude, to all the participants of the
workshop, who have worked hard to deliver what has become this special issue.
It is our sincere hope that this issue will become a major starting point for
further efforts to estimate environmental risks associated with the long-range
transport of pesticides.
H.F.G. van Dijk, W.A.J. van Put, P. de Voogt
The Hague, The Netherlands
ENVIRONMENTAL RISK ASSESSMENT FOR PESTICIDES IN THE
ATMOSPHERE; THE RESULTS OF AN INTERNATIONAL
WORKSHOP
ROBERTGUICHERIT', DICKJ. BAKKER', PIM DE VOOGT2, FREDERIK VAN DEN
BERG3, HARRIE F. G. VAN DIJK4' and W. ADDO J. VAN PUL'
1 TNO Institute of Environmental Sciences. Energy Research and Process Innovation. P. 0. Box
342, NL-7300 AH Apeldoorn, the Netherlands, 1 Amsterdam Research Institute for Substances in
Ecosystems (ARISE), University of Amsterdam (UvA), Nieuwe Achtergracht 166, NL-1018 WV
Amsterdam, the Netherlands, 3 Winand Staring Centre for Integrated Land, Soil and Water
Research (SC-DLO), P. 0. Box 125. NL-6700 AC Wageningen, the Netherlands, 'Health Council
of the Netherlands, P. 0. Box 16052, NL-2500 BB The Hague, the Netherlands, 5 National
Institute ofP ublic Health and the Environment (RJVM), P. 0. Box 1, NL-3720 BA Bilthoven, the
Netherlands
(author for correspondence. e-mail: hfg. [email protected])
Abstract. The Health Council of the Netherlands organised an international workshop on the fate
of pesticides in the atmosphere and possible approaches for their regulatory environmental risk
assessment. Approximately forty experts discussed what is currently known about the
atmospheric fate of pesticides and major gaps in our understanding were identified. They
favoured a tiered approach for assessing the environmental risks of atmospheric dispersion of
these chemicals. In the first tier a pesticide's potential for emission during application, as well as
its volatilisation potential should be assessed. Estimates of the former should be based on the
application method and the formulation, estimates of the latter on a compound's solubility in
water, saturated vapour pressure and octanol/water partition coefficient. Where a pesticide's
potential for becoming airborne exceeds critical values, it should be subjected to a more rigorous
second tier evaluation which considers its toxicity to organisms in non-target areas. This
evaluation can be achieved by calculating and comparing a predicted environmental
concentration (PEC) and a predicted no-effect concentration (PNEC). By applying an extra
uncertainty factor the PNEC can be provisionally derived from standard toxicity data that is
already required for the registration of pesticides. Depending on the distance between the source
and the reception area, the PEC can be estimated for remote areas using simple dispersion,
trajectory type models and for nearby areas using common dispersion models and standard
scenarios of pesticide use. A pesticide's atmospheric transport potential is based on factors such
as its reaction rate with OH radicals. It should be used to discriminate between those compounds
for which only the risks to nearby ecosystems have to be assessed, and those for which the risks
to remote ecosystems also have to be determined. The participants were of the opinion that this
approach is, in principle, scientifically feasible, although the remaining uncertainties are
substantial. Further field and laboratory research is necessary to gain more reliable estimates of
the physico-chemical properties of pesticides, to validate and improve environmental fate models
and to validate the applicability of standard toxicity data. This will increase both the accuracy of
and our confidence in the outcome of the risk assessment.
Keywords: atmospheric fate, atmospheric transport, deposition, emission, long-range transport,
pesticides, registration, remote area, risk assessment, transformation
Water, Air, and Soil Pollution 115: 5-19, 1999.
© 1999 Kluwer Academic Publishers.
6 R. GUICHERIT ET AL.
l. Introduction
Around the world, pesticides are used on a large scale in agriculture. However,
the last decades have seen an increase in public and political concern about the
possible side effects of pesticide use and this has resulted in many countries
implementing legislation to control the registration of pesticides. This
legislation requires risk assessments on human health and environmental
impact to be conducted prior to registration. To date risk evaluation procedures
have given scant consideration to the atmospheric fate of pesticides despite
many having been detected in the air and in rainwater, not only in agricultural
areas, but also in nearby and remote nature reserves. Atmospheric transport is
generally considered to be an important contamination pathway of such
non-target areas. This applies not only to the older organochlorine insecticides,
the use of which has been abandoned or severely restricted in many
industrialised countries, but also to many modem ones.
The Health Council of the Netherlands organised a workshop on 'Fate of
pesticides in the atmosphere; implications for risk assessment', which was held
at Driebergen, the Netherlands, from the 22nd to the 24th of April, 1998.
Participation was based solely on personal expertise in the area, and not on
affiliation. Almost 40 experts (see the list of participants elsewhere in this
issue) from industry, governmental organisations and academia were invited to
discuss what is presently known about emissions of pesticides to the
atmosphere, their transformations and transport in the atmosphere, and their
exchange between the atmosphere and surfaces on the earth. The discussions
focused on these physico-chemical processes rather than on the possible human
and environmental impact in non-target areas. It is recognised that these two
aspects are different fields of expertise, which is why the organising committee
focused on the physico-chemical aspects during the workshop. However,
impact issues were taken into account when possible approaches to risk
assessment were considered.
The objectives of the workshop were (i) to review the current scientific
understanding of the atmospheric fate of pesticides, (ii) to consider possible
risk assessment approaches, that can constitute a basis for the development of
statutory environmental criteria for use in registration procedures which limit
the dispersion of pesticides via the atmosphere, and (iii) to determine if the
current level of knowledge is sufficient for these criteria to be feasible. This
paper presents the main findings and conclusions ofthe workshop.
2. Background information
Participants were given an informative introduction to the topic of atmospheric
transport of pesticides through a series of keynote lectures. In these, invited
speakers summarised the available evidence from monitoring studies of
non-target areas contaminated by airborne pesticides and also deliberated on
ENVIRONMENTAL RISK ASSESSMENT FOR PESTICIDES IN THE ATMOSPHERE 7
how the organisms and ecosystems may be affected. Hites presented results on
the atmospheric fate of organochlorine pesticides. By analysing tree bark
samples from around the world, he could confirm the hypothesis that more
volatile compounds like hexachlorobenzene and hexachlorocyclohexanes are
subject to global fractionation and cold condensation, resulting in their
accumulation at higher latitudes. He also presented long-term measurements
from the Great Lakes area, which show that organochlorine concentrations in
the air are steadily decreasing. From this he extrapolated that by the middle of
next century they will be virtually eliminated. This data demonstrates the
success of regulatory measures, which restricted or banned many of these older
pesticides.
From a regulatory viewpoint, modem pesticides are probably of more
interest than those already banned, although knowledge of the atmospheric fate
of organochlorine pesticides will help to increase our understanding of the fate
of the modem compounds. Van Dijk and Guicherit (this issue) summarised the
evidence from monitoring studies which show that modem pesticides are also
subject to atmospheric dispersion. It is clear that many of them, such as
triazine, acetanilide and chlorophenoxy herbicides, and organophosphorus
insecticides, commonly occur in air, rainwater and fog in Europe and North
America and probably throughout the world. Concentrations in the air range
from several pg/m3 to many ng/m3 and in rainwater from a few ng!L to several
Jlg/L. Concentrations in fog are even higher. Deposition levels are in the order
of several mg/ha/yr to a few g/ha/yr. From their presence in rather remote areas
it can be inferred that several of these compounds are transported over
hundreds, and in some cases probably thousands, of kilometres, since input
other than via atmospheric routes can be ruled out.
Van Straalen stressed the scantiness of information relating to the effects
of modem pesticides on organisms and ecosystems in non-target areas (Van
Straalen and Van Gestel, this issue). He suggested that the risks in remote areas
could be assessed in a similar way to those at and near application sites, i.e. by
calculating a PEC (predicted environmental concentration) over PNEC
(predicted no-effect concentration) ratio. The PNEC could be derived from the
toxicity data (a part of the standard information required to support the
registration of a product). The PEC in a non-target area could be estimated
from the recommended application rate, emission factors, atmospheric
residence time and persistence in soil and water. Van Straalen showed that the
concentrations in soil or water in the non-target area can only be higher than at
the application site if the residence time in the non-target area is one to two
orders of magnitude longer. To compensate for the large uncertainty he
proposed that the maximum acceptable ratio between PEC and PNEC be
increased by an extra safety factor.