Biomarker response and health of polychlorinated biphenyl- and chlordane-contaminated paddlefish from the Ohio River basin, USA

Fifty paddlefish (Polyodon spathula) collected from two sites on the Ohio R iver and from one site on the Cumberland River, USA, were examined to deter mine gonad polychlorinated biphenyl (PCB) and chlordane concentrations, amo unts of plasma sex steroids (testosterone and estradiol), hepatic microsoma l ethoxyresorufin-O-deethylase (EROD) activity, and the presence of immunor eactive cytochrome P450 1A (CYP1A) protein. Percent hatch and liver, spleen , and kidney histology were also determined. Gonad PCB and chlordane concen trations were significantly higher in Ohio River paddlefish than in Cumberl and River paddlefish. Gonad PCB and chlordane concentration and gonad perce nt lipid were correlated in Ohio River paddlefish. Five of 10 Ohio River eg g samples exceeded the Food and Drug Administration's action limit for chlo rdane (0.30 mug/g). Polychlorinated biphenyl congener-specific analysis det ected predominantly the tetra-, penta-, and hexachlorobiphenyls in paddlefi sh testes. Plasma testosterone levels were significantly lower in males col lected from the upper Ohio River site than those collected from the lower p art of the river. There was no measurable hepatic microsomal EROD activity in any of the 50 paddlefish collected from the three sites. Western blottin g analysis confirmed that a rabbit antitrout CYP1A1 IgG antibody did not re cognize a CYP1A protein in paddlefish liver microsomes. Percent hatch was n ot significantly different in eggs collected from the Cumberland (88-96%) a nd Ohio Rivers (90-95%). Histological analysis of liver, spleen, and kidney detected the presence of hepatic steatosis and hemosiderosis, splenic lymp hoid cell depletion, and hyperplasia of interrenal and chromaffin tissues. Immunosuppression, hepatic metabolic disorders, and altered neuroendocrine function may be occurring in Ohio River paddlefish. Results presented here suggest that organochlorine exposure may be jeopardizing the long-term heal th of Ohio River paddlefish and that additional investigation of contaminan t effects on immune system function and hormone levels in paddlefish is war ranted.