A new intergovernmental study of pollution in
the Arctic has reported on concerns about levels of many persistent organic
pollutant contaminants, and recommends that emission controls are an essential
prerequisite to reduce exposure to humans and to protect wildlife.
The Arctic Monitoring and Assessment Programme (AMAP) was
established in 1991 by the ministers of the eight Arctic countries and charged
with preparing an assessment of the state of the Arctic environment with respect
to defined pollution issues. Accordingly, between 1991 and 1996 AMAP designed
and implemented a monitoring programme and conducted its first assessment. About
400 projects delivered data to AMAP for consideration.
The ensuing report, of mammoth size, comprises fully
referenced, comprehensive, technical and scientifically presented assessments of
the available and validated data. Even with this amount of information
scientists contributing to the report are still concerned that there are too
many gaps in our understanding of the pollution threats to the fragile Arctic
ecosystem.
The persistent organic pollutants (POPs) group of chemicals
are identified as the primary concern. Pesticide and pesticide-contaminant POPs
included in the study were aldrin, dieldrin, chlordane, DDT, hexachlorbenzene,
technical HCH [a mixture of alpha, beta and gamma and delta
hexachlorocyclohexanes], toxaphene, endosulfan, and tributyltin. All POPs
considered by the AMAP monitoring programme have been found in air, snow, water,
and/or wildlife in the Arctic.
Monitoring of air in the Arctic has shown that levels of
lindane (gamma HCH) and chlordane are correlated with long-range transport from
usage in the mid-latitudes of North America, Europe and Asia. The highest levels
of alpha HCH in the world's oceans are found in the Canada Basin and Canadian
Arctic Archipelago. Exceptionally high HCH levels are found in Russian river
water, especially the Ob (in north, central Russia). Ratios of gamma-HCH to
alpha HCH indicate use of lindane.
The infamous DDT is still widespread in the Arctic
environment. Despite being widely restricted in some countries, DDT is still
used for public health mosquito control in many tropical countries. The data for
levels of DDT in Russian rivers, while reflecting some analytical quality
assurance problems, show extraordinarily high residue levels when compared with
urban areas of North America and western Europe. Levels of DDE, a breakdown
product of DDT, in the Canadian population of tundra peregrine falcons, are
still considered high enough to cause egg shell thinning.
High levels of toxaphene were reported in fish higher up in
the Arctic food chain. Toxaphene, another POP-used as an insecticide in
Caribbean cotton production-has been found in Greenland halibut at levels that
may be high enough to affect fry bone development and increase mortality during
spawning. An extra concern is that very little information is available on the
general toxicity of this chemical in animals.
The anti-fouling paint, tributyltin, is probably causing
imposex (see also p.16) in Arctic invertebrates in some harbours.
Overall, the report concludes it is unlikely that levels of
these POPs are declining in the Arctic environment. And it is not just older or
defunct products that are of concern. The production and use of new organic
chemicals, including new generation pesticides, are identified as potential
threats.
In some cases, a number of Arctic species have high enough
POP levels to cause adverse effects. Therefore the report recommends:
monitor levels of POPs in wildlife and the wider environment so that levels can be better compared over time and by geographical location, and improving understanding of transport and fate process
refine and develop methods of determining subtle biological effects and relate POP levels to these effects
improve the ability to assess biological effects in organisms and health effects in humans
continue to promote measures to reduce
levels of POPs in the environment. (DB)
AMAP Assessment Report: Arctic Pollution
Issues, AMAP Secretariat, PO Box 8100, N-0032, Oslo, Norway, 1998, 859pp.
[This
article first appeared in Pesticides News No. 42,
December 1998, page 18]