The overall goal of the proposed work is to develop a comprehensive, multicompartmental model to study the fate and behaviour of POPs in the Baltic Sea environment. POPs enter the region by being either advected into the atmosphere and the aquatic environment or released from emission sources within the region itself. Because these pollutants are semi-volatile, they will undergo repeated cycles of deposition and reevaporation. Soils, vegetation, water bodies and sediments constitute storage reservoirs, acting both as sinks and sources of POPs. Eventually, they are permanently taken out, being advected out of the region, or degraded or irreversibly stored (burial in deeper sediment layers). The following POPs have been selected for the proposed study: hexachlorocyclohexanes (HCHs), polychlorinated biphenyls (PCBs), hexachlorobenzenes (HCBs), dichloro-diphenyl-dichloroethane (DDE), benzo(a)pyrene (B(a)P), dibenzodioxins, and dibenzofurans.
Specific objectives of the proposed study are to:
- develop, evaluate, and use a non-steady state multimedia mass balance modelthat describes the fate of selected POPs in the Baltic Sea environment, inorder to:
--examine physical, chemical, and biological processes resulting in the migration of POPs through the individual environmental compartments,--describe meteorological, chemical, physical, and biological parameters affecting the mobility of POPs in the environment,
--assess the relative importance and absolute magnitude of various chemical inputs to the Baltic Sea, namely autochthonous sources vs. advective import, atmospheric vs. riverine sources, and old vs. new sources (i.e. environmental reservoirs vs.current emissions),
--describe and possibly explain observed spatial patterns and temporal trends in the fluxes, concentrations, and relative compositions of various POPs within the Baltic Sea environment,
--evaluate the reltive importance of degradation, sediment burial, export in the atmosphere and outflow to the North Sea as loss mechanisms of POPs from the Baltic Sea,
-review information on present emissions and fluxes of the studied POPs to air, soil and water in the Baltic region and assess the emission input from surrounding regions within and outside Europe,
- assess historical emissions within and outside the study region for the last 2 decades, - develop an emission data base for modeling purposes, - complete and update existing data base of levels of POPs in the countries around the Baltic Sea and use these data for verification of model results, - prepare a set of recommendations with respect to the exposure and risk assessment for POPs in the Baltic Sea region.
It is expected that the model results will contribute to the explanation of several important aspects of the fate of POPs in a regional marine environment and its catchment area. The influence of (i) seasonal fluctuations, (ii) geographical gradients, (iii) sea-air-land interactions, and (iv) long-term chanqes of POPs on their environmental behavior will be presented. KEYWORDS: Organic pollutants, Cycling model, Baltic, Emission, Deposition, Sediments, Fish, Degradation
Funding SchemeCSC - Cost-sharing contracts