POP Contamination on European and Hemispherical Scale

EMEP Status Report 4/2002

V.Shatalov, A.Malanichev, S.Dutchak

ABSTRACT

Present Status report describes a progress in the investigation of persistent organic pollutants (POP) long-range transport and accumulation in the environment achieved under EMEP in 2002. The work was performed in accordance with the EMEP work-plan for 2002 [ECE/EB.AIR/75, Annex IV].

The main objectives of the work-plan for 2002 are:
- Assessment of transboundary transport of benzo[a]pyrene (B[a]P): calculation of B[a]P transboundary transport and contamination of European region for 1999.
- Evaluation of PCDD/F transport and accumulation in various environmental compartments in 1999.
- Tentative simulation of PCBs and g-HCH transport and accumulation from European sources on the hemispheric scale (including the Arctic).

Main results of these activities are shortly described below.

According to calculations essential deposition fluxes are observed in regions with intensive B[a]P emissions: Poland, the Czech Republic, Slovakia, Germany, Lithuania and Latvia. For a considerable part of the territory of European countries B[a]P mean annual concentrations in the surface air reach 1 ng/m³ or higher. In some countries the exceedance of mean diurnal concentration of 1 ng/m³ can take place during more than 100 days a year.

The analysis of transboundary fluxes demonstrates that the highest B[a]P air concentrations caused by external emission sources take place in Slovakia, the Czech Republic and Hungary. High calculated values of B[a]P export are obtained for Germany, Poland and France.

The analysis of calculated spatial distributions of PCDD/F concentrations and depositions in the environment shows that these pollutants are widely spread over Europe. Relatively high soil concentrations in some parts of the Scandinavian Peninsula are obtained. They can be explained by the role of forests in the formation of soil contamination levels. Sea currents also contribute to PCDD/F long-range transport. The half-life of PCDD/Fs in the environment is estimated to be about 30 years.

The investigation of PCDD/F toxicity congener composition in emissions and the environment showed that to improve the assessment of PCDD/F contamination in the EMEP region the evaluation of transport of main PCDD/F congeners is important. However, with the accuracy about 50% pilot simulation of PCDD/F transport and accumulation can be made by the "indicator congener" 2,3,4,7,8-PeCDF properties.

Simulations of long-range transport of selected POPs in the EMEP region show that from 30 to 80% of their annual emissions (depending on a pollutant in question) are transported outside the EMEP region. For substances with high outflow from the region evaluation of transport and accumulation on the hemispheric/global scale is reasonable. Tentative calculations of POP long-range transport from European emission sources for 1990 were made for g-HCH, PCBs and HCB by the hemispheric version of the MSCE-POP model. These calculations showed that:
- Considered pollutants can reach remote regions such as Asia, the Arctic and North America.
- Among the considered pollutants HCB has maximum ability to long-range transport.

In line with the evaluation of pollution models for POP are further developed. In particular, wet deposition scheme, parameterization of atmosphere/soil and atmosphere/sea exchange modules have been modified.

The assessment of POP contamination is made in close collaboration with national experts and subsidiary bodies to the Convention on Long-range Transboundary Air Pollution (CLRTAP): the expert group on POP assessment (Working Group on Strategies and Review) and Working Group on Effects.

The preparatory work for the intercomparison of POP multicompartment transport models has been started.