MULTIGENERATIONAL STUDY OF THE EFFECTS OF CONSUMPTION OF PCB-CONTAMINATED CARP FROM SAGINAW BAY, LAKE-HURON, ON MINK - 1 - EFFECTS ON MINK REPRODUCTION, KIT GROWTH AND SURVIVAL, AND SELECTED BIOLOGICAL PARAMETERS

This study was conducted to determine the multigenerational effects of consumption of PCB-contaminated carp (Cyprinus carpio) from Saginaw B ay (Lake Huron) on mink (Mustela vison) reproduction and health and to examine selected biomarkers as potential indicators of polyhalogenate d hydrocarbon toxicity in mink. The mink were fed diets formulated to provide 0 (control),, 0.25, 0.5, or 1.0 ppm polychlorinated biphenyls (PCBs) through substitution of Saginaw Bay carp for ocean fish in the diets. To determine whether the effects of PCB exposure were permanent , half of the parental (P-1) animals were switched from their respecti ve treatment diets to the control diet after whelping the first of two F-1 generations. Effects of in utero and lactational exposure to PCBs on subsequent reproductive performance of the F-1 animals were examin ed by switching half of the first-year F-1 offspring (kits) to the con trol diet at weaning, while the other half was continued on their pare ntal diet (continuous exposure). Continuous exposure to 0.25 ppm, or m ore, of PCBs delayed the onset of estrus (as determined by vulvar swel ling and time of mating) and lessened the whelping rate, litters whelp ed by females continually exposed to 0.5 ppm, or more, of PCBs had gre ater mortality and lesser body weights than controls. Continuous expos ure to 1.0 ppm PCBs had a variable effect on serum T-4 and T-3 concent rations. Compared to the controls, there were significant differences in kidney, liver, brain, spleen, heart, and thyroid gland weights of t he mink continually exposed to 1.0 ppm PCBs. There was an increase in the incidence of periportal and diffuse vacuolar hepatocellular lipido sis in the P-1 mink with continuous exposure to increasing concentrati ons of PCBs. Plasma and liver PCB concentrations of the adult and kit mink were, in general, directly related to the dietary concentration o f PCBs and the duration and time of exposure. Short-term parental expo sure to PCBs had detrimental effects on survival oi subsequent generat ions of mink conceived months after the parents were placed on ''clean '' feed. The lowest observed adverse effect level (LOAEL) for dietary PCBs in this study was 0.25 ppm.