TOXIC AND BIOCHEMICAL EFFECTS OF 3,3',4,4'-TETRACHLOROBIPHENYL (CB-77) AND CLOPHEN A50 ON EIDER DUCKLINGS (SOMATERIA-MOLLISSIMA) IN A SEMIFIELD EXPERIMENT

In this study the possible toxic and biochemical effects of one intrap eritoneal dose of 5 or 50 mg kg-1 of 3,3',4,4'-tetrachlorobiphenyl (CB -77) or 50 or 200 mg kg-1 of Clophen A50 (CloA50) on 28-day-old eider ducklings (Somateria mollissima) were investigated After ten days, no significant differences could be observed in any of the toxic and bioc hemical parameters studied, apart from ethoxyresorufin (EROD) activity , when comparing group average values of the dosed and control animals . However, significant correlations were observed at day 10 after expo sure between the individual internal PCB concentration and body weight gain and beak length growth (negative correlations in the CloA50 grou ps); relative liver weight and cytochrome P4501A activity (positive co rrelations in CB-77 and CloA50 groups); plasma thyroid-hormone and hep atic retinoid levels (negative correlations in CB-77 groups); and plas ma retinol levels and the ratio plasma retin/hepatic retinyl palmitate (positive correlations in CB-77 groups only). Animal activity was sig nificantly reduced in the group that received 50 mg CB-77 kg-1. These observations indicate that eider ducks are a sensitive species to PCB toxicity and may be at risk for development of adverse health effects in relatively highly contaminated areas such as the Waddenzee.