Assessment of biological effects of chlorinated hydrocarbons in osprey chicks

Osprey (Pandion haliaetus) eggs were collected during 1995 and 1996 at seve n sites along the Fraser and Columbia River systems of British Columbia, Ca nada, and Washington and Oregon, USA. Fifty-four eggs were, placed into a l aboratory incubator. Thirty-eight of the hatched chicks were sacrificed wit hin 24 h. Hatching success did not differ among sites and therefore between treatment and reference areas. Residual yolk sacs of eggs collected downst ream of the large bleached-kraft pulp mill at Castle.-ar contained greater mean concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, 2,930 ng/ kg lipid) compared with reference sites such as the Nechako River, an upper tributary of the Fraser system (33.7 ng/kg). Total polychlorinated bipheny ls (PCBs) in yolk sacs were also higher at Castlegar and in samples from th e Columbia River downstream of Portland, Oregon, compared with those from t he Nechako River. Concentrations of measured chemicals, including TCDD toxi c equivalents (TEQs), total PCBs, p,p ' -dichlorodiphenylethylene (p,p ' -D DE), and other organochlorines were not different in eggs that failed to ha tch compared with calculated whole-egg values for hatched eggs. There were significant biochemical responses; a hepatic cytochrome P4501A (CYP1A) cros s-reactive protein was detected in all samples tested and correlated positi vely with ethoxyresorufin o-deethylase (EROD) activity and yolk sac concent rations of TEQs and total PCBs. Tissue concentrations of vitamin A compound s varied among sites and correlated positively with yolk sac concentrations of TEQs and PCBs. Morphological, histological, and other physiological par ameters, including chick growth, edema, deformities, and hepatic and renal porphyrin concentrations, neither varied among sites nor showed concentrati on-related effects.