PCB and PAH impacts on cytochrome P-450-dependent oxidases in roach (Rutilus rutilus) from the Seine River (France)

Roach were sampled in the Seine River along a gradient of polyaromatic hydr ocarbon (PAH) conclusions at three stations: Marnay upstream of Paris and E pinay and Poses downstream of Paris. Two hepatic monooxygenase activities: EROD (ethoxyresorufine-O-deethylase) and AE (aldrin epoxydase) and muscle r esidues of PCBs and PAHs were investigated during three periods of the year (before spawning, during spawning, and postspawning). Before spawning, ERO D and AE activities were significantly correlated with muscle PCB levels (p less than or equal to 0.05 for both activities) and with muscle PAH levels (p less than or equal to 0.05 for both activities) at the three stations. Cd was not inversely related to monooxygenase activities. During spawning, enzymatic activities remained low and were not correlated to pollutant leve ls. Postspawning EROD and AE activities were again significantly related to muscle PCBs (p less than or equal to 0.05 for both activities). Thus, inve stigations of EROD and AE activities may be considered as a reliable tool f or biomonitoring of PCB or PAH exposure, as far as appropriate conditions a re observed.