Concentrations of PCBs and other organochlorine compounds in eels (Anguilla anguilla, L.) of the Vanajavesi watercourse in southern Finland, 1990–1993

As a consequence of stocking, the Vanajavesi watercourse has become one of the most important eel waters in southern Finland. In the upper reaches of the waterway, Lake Kernaalanjärvi (410 ha) was severely loaded in the 1956–1984 period by a single paper mill, which discharged a total of more than 1000 l of PCB compounds into the water. For this reason it has been impossible to use the pike, pike-perch and bream from this lake for human consumption. However, the effect of the discharges with respect to these species has only been a local one. In 1989 and 1990, some PCB measurements were also made on a number of eels. The highest measured PCB concentrations (33.8 mg kg−1 fresh wt.) of these were up to seven times higher than for pike, and 15 times higher than pike-perch, in the same area. As a result of this study, a more extensive study concentrating on eels was initiated at the Finnish Game and Fisheries Research Institute. From 1990–1993, a total of 54 eels were trapped in the Vanajavesi waterway and determinations for PCBs and other organic chlorine compounds were made. In this case the highest PCB level measured was only 5.1 mg kg−1, some 70 km downstream of Lake Kernaalanjärvi. In general, however, the concentrations were inversely proportional to the distance downstream from the lake. In Lake Kernaalanjärvi itself, the average PCB concentration was 1.7 mg kg−1. Of all the eels studied, 12.9% were unfit for human consumption (PCB concentration > 2.0 mg kg−1) according to the National Board of Health directive.