Chemical pollution and ecotoxicology

Abstract

1. Baltic Sea organisms appear to be particularly sensitive to persistent hazardous substances because many of them are physiologically stressed in their brackish-water environment. 2. The profile of chemical pollution of the Baltic Sea has changed during the past decades with reductions in the concentrations of many "legacy contaminants" such as DDTs, PCBs, dioxins and trace metals. However, many of these compounds degrade very slowly and their concentrations are still unacceptably high. 3. Radionuclides from the Chernobyl nuclear power plant accident still contaminate the Baltic Sea but are slowly returning to pre-Chernobyl levels. 4. The growing oil tankers traffic is increasing the risk of major oil spills in the Baltic Sea. In addition, dumped chemical weapons on the seafloor are likely to leak due to corrosion. 5. An increasing amount of "contaminants of emerging concern", e.g. Industrial chemicals, pharmaceuticals and ingredients of personal care products, most of them with unknown toxicity and environmental behaviour, ends up in the Baltic Sea. 6. Standardised biotests are widely used to examine the quality of water and sediments, but despite their usefulness in this context they often lack ecological relevance. 7. The term "biomarker" is used for a distinctive biological or biologically derived indicator (e.g. Gene expression, enzyme activity, imposex, behaviour, growth, reproduction) of exposure to or effects of hazardous substances in the environment. 8. Biomarkers can be used to assess the effects of hazardous substances in organisms from different trophic levels. They allow rapid detection of potential toxic exposure and damage by providing information on the actual health status of organisms, including the effects of non-bioaccumulative substances and mixture toxicity. A major challenge remains in linking biomarker responses observed in field-collected organisms to effects at the population and community levels. 9. The accelerating climate change is expected to cause alterations in the bioavailability and toxicity of chemicals and their spread in the ecosystem due to changing environmental conditions.