Chemistry Reference
In-Depth Information
6 Future Perspectives
Under the Stockholm Convention and other agreements, the European countries
compelled themselves to eliminate or reduce the production, use and emissions of
POPs and to decrease human and ecosystem exposure. Now, one aspect under
discussion is the extension of the pollutants with POP properties to new compounds
needing environmental monitoring. Several candidates have been intensively stud-
ied in the recent years. One obvious requirement concerns the proven toxicity
effects of the molecules under study.
The emission reports and air concentration measurements indicate that the
atmospheric concentrations of most of the well-studied POP, e.g. PCBs, HCH and
HCB in Europe, declined between 1990 and 2000 but decreased more slowly during
the last decade. The overall reduction results from the international actions
undertaken in the last decades for the elimination/reduction of production and use
of these compounds. However, there are still primary emissions from diffuse
sources, such as old stockpiles or old equipment, which are often hard to target.
Model calculation using different policy scenarios show that between now and 2020,
little decrease on the emissions should be expected for PCBs, HCB, HCHs and PAHs
[
79
] because most of the reduction programmes have already been completed. The
ubiquitous presence of these persistent compounds in the European ecosystems
involve that soils, vegetation and water bodies constitute secondary emission
sources for POP re-emissions to the atmosphere [
10
]. This scenario outlines the
need for a comprehensive assessment of the dynamics of POPs in the European
ecosystems, particularly in the mountain areas in which freshwater is primarily
accumulated. The interdependences between long-range transport, degassing and
deposition involve a background contamination of these water bodies at the onset of
water accumulation in lakes and, subsequently, when transferred to rivers.
In this context, the progressive warming associated to human-driven climate
change may also add to the redistribution of POPs in the European environment. At
increasing ambient air temperatures, higher degassing of POP flux towards the
atmosphere in high mountain regions is expected [
83
]. The increase of ambient air
temperatures in the Arctic region has also been related to the re-volatilisation of POP
to the atmosphere [
84
]. In the European continent, the accelerated retreat of glaciers
due to higher temperature has also led to an induced release of POP tomeltwater that is
reflected in the increasing POP concentrations in sediments from lakes that are fed by
this water. These changes have not been observed in lakes without glacier input [
85
].
References
1. AMAP (1998) Arctic pollution issues: a state of the arctic environment report. Arctic Moni-
toring and Assessment Programme, Oslo
2. Grimalt JO, Fern´ndez P, Berdie L, Vilanova RM, Catalan J, Psenner R, Hofer R, Appleby PG,
Rosseland BO, Lien L, Massabuau LC, Batterbee RW (2001) Selective trapping of organo-
chlorine compounds in mountain lakes of temperate areas. Environ Sci Technol 35:2690-2697
