Some Indications Of Contaminant Effects On Baltic Cod (Gadus Morhua L.)

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The Baltic Sea has been exposed to severe human impacts. Apart from eutrophication and overfishing, contamination by known organic pollutants such as PAHs, PCBs and organochlorine pesticides are of major concern, even though the levels of the latter two have decreased during the past two decades. Additionally, novel scarcely known and unknown contaminants may also cause biological effects. In the EU-funded project 'Biological Effects of Environmental Pollution in marine coastal ecosystems - BEEP', we assessed to what extent Baltic cod is affected by contaminants. During a cruise in December 2001, cod were collected in the western and southern Baltic Sea, the somatic condition factor was estimated and different indicators (biomarkers) for contaminant exposure and biological effects were analysed. In addition, various PCBs and organochlorine pesticides were measured in cod liver. The results obtained demonstrate that the contaminant levels in the Baltic are likely to influence the physiology of cod: in almost all specimens analysed, hepatic EROD activity in the liver was readily measurable, and 1-OH-pyrene, a common PAH-metabolite, was detectable in bile. Both features indicate an induction of the CYP1A biotransformation system in response to toxic substances. The occurrence of DNA adducts in some of the specimens provide evidence for the presence of genotoxic substances. Acetylcholinesterase (AChE) was measurably inhibited, an indication of exposure to organophosphates and related compounds, particularly in specimens taken off the Polish and Lithuanian coast. In general, spatial differences in the biomarker responses as well as contaminant loads were found, suggesting differences in concentration and mixtures of organic contaminants in this ecosystem.