Organochlorine residues in River Po sediment: testing the equilibrium condition with fish.

Organochlorine residues have been determined in sediment samples collected in the River Po, during 1980-1982 at five sampling stations. Significant higher levels have been observed in a deposition area after the confluence of a very polluted tributary. No significant differences could be observed with respect to the sampling period. Residue concentrations in sediment were correlated with the organic matter content. By using soil partition coefficients and bioconcentration factors in fish, pesticide and PCB concentrations in fish have been calculated from sediment values and compared with measured values from a previous investigation. Tentatively a quality criterion for PCB in sediment is proposed.