Investigation of the Effects of Perchlorate on Thyroid and Reproductive System Function in Goldfish
PENNSYLVANIA STATE UNIV STATE COLLEGE SCHOOL OF FOREST RESOURCES
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With the development of new analytical detection capabilities, perchlorate contamination has been found in ground and surface waters across the United States U.S.. Perchlorate, as ammonium perchlorate, is an oxidant used in solid rocket fuels hence, sources of contamination generally occur near military test sites and chemical manufacturing plants. The perchlorate anion ClO4 - is known to inhibit thyroid function in mammals. In some locations in the U.S., perchlorate has been found at part per million concentrations in surface water inhabited by fish. To test the hypothesis that exposure to environmentally relevant concentrations of perchlorate can impact fish thyroid and reproductive function, adult male and female common goldfish Carassius auratus were exposed in a laboratory flow-through exposure system for 30 days to four concentrations of perchlorate ranging from 14 ppb to 31 ppm, along with controls. Exposure was continued to 60 d for an additional set of controls and 31 ppm treatment groups. Gonadosomatic index GSI, gonad histology, and plasma sex steroids 17 -estradiol, testosterone, and 11-ketotestosterone were examined to assess reproductive function. Thyroid activity was assessed by use of a nonparametric rank-order assessment method developed for fish during this study. Significant increases in head kidney thyroid activity occurred at 1200 ppb and 31 ppm in females and at 31 ppm in males. Pharyngeal thyroid activity increased in both male and female goldfish exposed to 31 ppm perchlorate. Exposure to perchlorate concentrations up to 31 ppm for 30 or 60 d had no effect on GSI. Some statistically significant effects on plasma sex steroid concentrations were observed for both sexes, but the differences were small and concentrations remained within normal ranges previously reported for goldfish in this reproductive state.
- Anatomy and Physiology
- Inorganic Chemistry