Reproductive effects of long-term exposure to bisphenol a in the fathead minnow (Pimephales promelas)

Bisphenol A (BPA), a high-volume chemical used to make polycarbonate plasti c, epoxy resins, and other chemicals has been reported to be weakly estroge nic. To investigate the effects of long-term exposure to Bisphenol A, a mul tigeneration study was conducted in which fathead minnows (Pimephales prome las) were exposed to water concentrations of BPA in the range from 1 to 128 0 mug/L. In this paper, we report the growth and reproductive effects of BP A on sexually mature adults in the F0 generation (after 43, 71, and 164 d o f exposure) and the effects on hatchability in the Ft generation. Mean meas ured concentrations of BPA in the water for all doses, over a 164-d exposur e period, were between 70% and 96% of nominal. An inhibitory effect of BPA on somatic growth (length and weight) occurred in adult male fish exposed t o 640 and 1280 mug/l. (after 71 and 164 d). BPA induced vitellogenin synthe sis (VTG; a biomarker for estrogen exposure) in males at concentrations of 640 and 1280 mug/l after 43 d and 160 mug/L after 71 d. In females, plasma VTG concentrations were elevated above controls only after 164-d exposure t o 640 mug/L. Inhibition of gonadal growth las measured by the gonadosomatic index) occurred in both males and females at concentrations of 640 and 128 0 mug/L after 164 d. In males, a concentration of 16 mug/L altered the prop ortion of sex cell types in the testis, suggesting inhibition of spermatoge nesis. Concentrations of BPA that induced VTG synthesis and affected gonada l development were lower than those that resulted in discernible effects on reproductive output. Egg production was inhibited at a BPA concentration o f 1280 mug/L, and hatchability in the F1 generation was reduced at a BPA co ncentration of 640 mug/L (there were not enough eggs spawned in the 1280 mu g/L group for hatchability studies to be conducted). The results demonstrat e that BPA acts as a weak estrogen to fish when administered via the water, with effects on breeding at and above 640 mug/L.