Organochlorine distribution and mono-orthosubstituted PCB pattern in the roach (Rutilus rutilus) from the River Seine

Organochlorine levels (PCBs and pesticides) were determined by high resolution gas chromatography (HRCG) in the roach and in the water from stations of the River Seine with different pollution levels, in spring and autumn. An inverse relationship between size and pollutant levels was shown in the roach from highly polluted stations (p ≤ 0.001) but failed to be found at the slightly polluted ones. No changes in the PCB pattern were found in relation to the size, either in fish from the highly polluted sites or in fish from the slightly polluted ones. At both types of sites, a fall of the PCB contents occurred in spring as compared to those of autumn; this appears to be in relation to spawning. Concerning the PCB pattern, PCB 153 and PCB 101 are classically the major components found in both the commercial mixtures and the roach. The mono-orthosubstituted and the less chlorinated components showed much lower levels in the roach than in the commercial mixtures; this appears to be in accordance with the high metabolic induction ability of those types of congeners.