ECOTOXICOLOGICAL AND HEALTH RISKS CAUSED BY CONTAMINATED RIVER KYMIJOKI SEDIMENTS.

Matti Verta, Markku Korhonen, Jouni Lehtoranta

Finnish Environment Institute, P.O.Box 140, FIN-00251 Helsinki, Finland

Terttu Vartiainen, Hannu Kiviranta

National Public Health Institute, P.O.Box 95, FIN-70701 Kuopio, Finland

Jussi Kukkonen, Heikki Hämäläinen

Department of Biology, University of Joensuu, P.O.Box 111, FIN-80101 Joensuu, Finland

Pirjo Mikkelson, Helena Palm

Department of Chemistry, University of Jyväskylä, P.O.Box 35, FIN-40351 Jyväskylä, Finland.

Kymijoki, the fourth largest river in Finland, is situated in the south eastern corner of the country and discharges to the Baltic Sea. The area has long traditions in paper industry and the river has been heavily polluted by e.g. pulp mill effluents as well as the chemical industry. Recently, polychlorinated diphenylethers (PCDE), dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) have been detected from river sediments. These compounds occur as impurities of a wood preservative (main product polychlorinated phenols, PCPs), manufactured on the upper Kymijoki from the 1940s to 1984.

A joint research project was launched in 1996 in order 1) to define the (spatial) extent of the contamination of the river and its estuary, 2) to elucidate the transport mechanisms of the compounds in the river channel and accumulation into biota, 3) to investigate ecotoxicological effects of the contaminated areas on the aquatic biota, 4) to assess the health risks for humans, and 5) to find out the restoration needs and preconditions of the contaminated environments.

Preliminary results show extremely high concentrations of PCDEs and PCDD/

Fs in sediments at the upper course of the river. Congeners, typical to impurities, dominate in river sediments. The fish analyzed thus far have shown highly elevated PCDE levels, but only slightly elevated PCP or PCDD/F levels (as ITEQ) compared with the levels in fish in the Baltic Sea. High toxicity to sediment exposed micro-organisms and high frequencies of mentum deformities in midge (Chironomus spp) larval populations were measured in areas of high pollutant concentrations in sediments but in some occasions at the lower River Kymijoki as well. The survival of midge larvae was not clearly affected by the pollutants, but growth and development tended to be slower in most contaminated sediments from the upper course of the river.

Preliminary analysis of PCDD/F's in the milk samples of mothers did not differ from the level in other locations in Finland. Preliminary blood samples from local fishermen at the coastal area showed high PCDD/F levels. An epidemiological cancer survey of the exposed population in River Kymijoki area is underway. Epidemiological studies among groups of people with significantly elevated prevalence of adverse health conditions will account for exposures to both PCDD/F's in fish from the River Kymijoki and from the Baltic Sea as well as for exposures to PCP compounds in potable water originated from River Kymijoki. Exposure models will be used retrospectively to reconstruct past events and to simulate future development.