Bioaccumulation of some polychlorinated dibenzo-p-dioxins and octachlorodibenzofuran in the guppy ( [formula omitted][formula omitted])

A study is reported which investigates the bioconcentration and dietary accumulation of some chlorinated dibenzo-p-dioxins congeners (PCDDs) and octachlorodibenzofuran (OCDF) in the guppy ( Poecilia reticulata ). Dietary bioaccumulation of the PCDD congeners and OCDF was insignificant. The bioconcentration factors of PCDDs and OCDF were approximately two orders of magnitude lower than those of polychlorinated biphenyls of similar 1-octanol-water partition coefficient. It is demonstrated that the low bioconcentration and dietary bioaccumulation factors of the PCDDs are due to rapid depuration of the chemicals from the fish. Metabolic transformation of the PCDDs in the fish is shown to be an important factor causing this rapid depuration. Metabolic transformation of the PCDDs appears to involve hydroxylation, probably mediated by the mixed function oxidase system.