Respiratory uptake kinetics of neutral hydrophobic organic chemicals in a marine benthic fish, Pseudopleuronectes yokohamae

摘要

We investigated the respiratory uptake kinetics of polychlorinated biphenyls (PCBs), organohalogen pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), and 2,2',4,4'-tetrabrominated diphenyl ether (BDE #47) in a marine benthic fish, Pseudopleuronectes yokohamae. The respiratory uptake efficiencies (Ew) of the chemicals, of which there have been no reports for the majority of persistent organic pollutants (POPs), were obtained by measuring the respiratory uptake rate constants (k_1) and the oxygen consumption rates of fish. Fish were exposed to water in which these chemicals were dissolved at environmentally relevant concentrations for 28 d, followed by 168 d of depuration in clean seawater. The k_1, and E_w values for 99 compounds were obtained, and they ranged from 2000 to 42000 L kg-lipid~(-1) d~(-1) and from 0.060 to 1.3, respectively. The E_w values of the chemicals, except for PAHs, tended to increase with increasing values of the log octanol-water partition coefficients (K_(ow)) of the chemicals up to a log K_(ow) of 5. For log K_(ow) in the range 3-5, the E_w values in this study were much lower than those in a published study (about one-third). As a result of analysis by a two-phase resistance model, the resistance of transport rates to the lipid phase in this study was lower than was the case in the published study. These findings indicate that the E_w predicted by the published study for log K_(ow) in the range 3-5 may differ among fish species and water temperature, and further study is needed.