UPTAKE OF PCBS IN FISH IN A CONTAMINATED RIVER SYSTEM - BIOCONCENTRATION FACTORS MEASURED IN THE FIELD

We have studied PCB concentration and domain (one to three congeners) distribution in water and fish along a gradient of a contaminated river system. The river was contaminated by a small lake that contains about 400 kg of PCB in the sediment. The PCB concentration in water in the outlet from the lake was 8.6 ng/L, which was 12 times higher than upstream. PCB concentration in fish from the lake was about 20 times higher than the concentration in fish from upstream lakes. The polluted lake considerably influenced domain distribution in both water and fish. The fish bioconcentration factors (BCFs) for low to highly chlorinated domains showed a bell-shaped curve. BCFs for low chlorinated PCBs were less than for more highly chlorinated ones, but for the largest molecules the BCFs were reduced. The bell-shaped curve remained also when domain numbers were transformed into corresponding log K-OW values. BCFs for the same domains were shown to vary between stations.