Metals and organochlorine compounds in fish from Latvian lakes.

Abstract

Organochlorines and metals have high toxicity and worldwide distribution in the aquatic environment. They are known to accumulate in sediments. In mollusks and fishes, they are bioconcentrated, even when released in minute quantities into the environment. This is important, as these chemicals have an adverse impact on species diversity, and accumulate in humans when seafood is consumed (Jaffar et al. 1988; Ruiter 1995). The nature and extent of accumulation and impact of persistent xenobiotics in water bodies depend on their sources; i.e. whether they are from industry, agricultural activities, transboundary transport with air masses (Sharif et al. 1993), geochemically determined elevated concentrations, or dissolution of mineral phases due to acidification of the environment (Iivonen et al. 1992). It is, therefore, important to analyze persistent xenobiotics (metals and organochlorines) in biota, even if the impact of anthropogenic pollution is minimal. Metal and organochlorine concentrations in fish in Latvia have never been reported. In Latvia direct point sources are found only in a few regions, while dominant metal sources in many cases appear to be transboundary transport of pollutants (Nikodemus and Brumelis 1994). Comparatively high biota contamination levels (HELCOM 1996) have been found in neighbouring countries (Sweden, Poland, Russia and Denmark), but data for comparison in Latvia is lacking.