EFFECT OF TEMPERATURE ON THE ACCUMULATION KINETICS OF PAHS AND PCBS IN THE ZEBRA MUSSEL, DREISSENA-POLYMORPHA

The role of temperature on the accumulation and elimination kinetics o f selected polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyl (PCB) congeners was examined for the zebra mussel, Dreissena polymorpha. Uptake and elimination rates were measured at intervals o ver a three year period in laboratory toxicokinetics studies in which zebra mussels were maintained at ambient field temperatures or acclima ted to higher or lower temperatures. The uptake rate coefficients (k(u )) for benzo(a)pyrene (BaP) and 2,2',4,4'5,5'-hexachlorobiphenyl (HCBP ) increased in proportion to temperature over a range from 4 to 20 deg rees C when measured at the field-collected temperature. Both k(u) and the elimination coefficient (k(u)) also decreased with increasing org anism size. However, no relationship with temperature was found for th e k(u) of BaP in the following year nor was there a relationship betwe en k(u) and temperature for pyrene and pentachlorophenol (PCP) when th e kinetics were measured at field-collected temperatures. In laborator y acclimation studies, k(d) for three compounds (BaP, HCBP, and PCP) s howed a significant positive relationship with temperature over the 4- 20 degrees C range. Pyrene accumulation kinetics however, still exhibi ted no relationship with temperature. These results contradict the con cept that uptake of contaminants changes over a season with temperatur e thereby, influencing contaminant toxicokinetics. Furthermore, the k( d) values observed for these compounds indicate that elimination was s low, and no relationship of k(d) was exhibited with water temperature, season, or year.