Toxicokinetics of DDE and 2-Chlorobiphenyl in Chironomus tentans
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- Lydy, M., Lasater, J. & Landrum, P. Arch. Environ. Contam. Toxicol. (2000) 38: 163. doi:10.1007/s002449910021
Uptake, biotransformation, and elimination rates for DDE and 2-chlorobiphenyl (2-CB) were examined using fourth instar midge larvae (Chironomus tentans) under a water-only exposure. A two-compartment model that included biotransformation described the kinetics for 2-CB and a one-compartment model was used for DDE. The uptake clearance coefficient (ku) was 65.96 ± 2.09 ml · g−1 midge · h−1 for 2-CB and 84.1 ± 2.7 ml · g−1 midge · h−1 for DDE. DDE demonstrated no measurable elimination, while 2-CB showed elimination with faster elimination of parent compound (kep = 0.100 ± 0.008 h−1) compared to the polar metabolites (kem = 0.073 ± 0.016 h−1). The biotransformation rate for 2-CB (km = 0.031 ± 0.005 h−1) appeared to be time-dependent with faster rates at the beginning of the accumulation process slowing to a constant once the midge was loaded with chemical. Experimental results indicate a difference in the ability of C. tentans to eliminate 2-CB and its metabolites more quickly than DDE, and these differences were related to the bioconcentration potential of the compounds.