Sediment desorption of PCB congeners and their bio-uptake by dipteran larvae

Sediment desorption of PCB congeners and their bio-uptake by Chironomus tentans Fabricus were investigated in a continuous flow system. The desorption of 71 congeners (in Aroclors 1221, 1016, 1254 and 1260) determined by glass capillary gas chromatography could be described by a first order function. The release rate of the individual congeners was inversely related to their octanol/water partition coefficients (K_ow). The depth of mobilization generally decreased with the number of chlorine substitutions and was inversely related to K_ow.Bio-uptake of the congeners by Chironomus tentans Fabricus was selective with the bio-uptake factor being highest for those with 2–4 chlorines. There was no correlation between the factor and either K_ow or desorption rate from the sediments.