Environmental fate and bioavailability of wood preservatives in freshwatersediments near an old sawmill site

Impacts of an old contaminated sawmill site located in Eastern Finland were studied, with emphasis on transportation and bioaccumulation of wood prese rvatives in the surrounding water system. To assess the transportation of c hlorophenols and chromated copper arsenate (CCA) from the sawmill to the ne arby lake, the concentrations of these compounds in selected sediment sampl es were analyzed. To assess the contribution of a pulp mill further upstrea m, the concentration of extractable organic halogens (EOX) was analyzed. Bi oaccumulation of wood preservatives from sediments was examined using Lumbr icus variegatus as test organism. In sediments collected from the sawmill a rea, concentrations of chlorophenols, arsenic, chromium and copper were hig h. In the surrounding area the concentrations of these compounds were sligh tly elevated at some sampling points but were mostly within the natural ran ge of variation. Thus, it can be concluded that transportation of wood pres ervatives from the sawmill area to its surroundings is fairly low. However, 60 mug/l of arsenic and 50 mug/l of copper were found in water taken from a brook that runs through a landfill area of the sawmill to the nearby rive r, and the concentration of arsenic in the surface sediment at one sampling point in the lake was slightly elevated. The total amount of organohalogen s in sediment was higher in the river and the lake than in the sawmill area . Of all the wood preservatives studied, only arsenic was found to bioaccum ulate in present conditions, reaching a tissue concentration of 362 mug/g d w in organisms exposed for 28 days to sediment from the brook. High concent ration of arsenic in oligochaeta tissue was related to high concentration o f arsenic in the pore water. (C) 2001 Elsevier Science Ltd. All rights rese rved.