Research Product

The evaluation of multi-generation, population-level impacts is particularly important in the risk assessment of endocrine disrupting compounds (EDCs) because adverse effects may not be evident during the first generation of exposure. Population models were developed for the sheepshead minnow (Cyprinodon vark?gahus) exposed to 17B-estradiol (E2) for two complete generations (FI, F2) to determine population-level effects of continued exposure to a model estrogen. Stage structured matrix models were used to determine interactions between treatment concentration and the number of generations exposed. Reproduction was significantly reduced in both the 0.08 and 0.2 ug E2/L in both generations and embryo and larval stages experienced reduced survival at 0.2 ug/L in the second generation only. However, increased female:male sex ratio in these treatments compensated for the loss in reproductive output and significant population-level effects only occurred in the 0.2 ug E2/L treatment of the F2 generation. The F2 0.2 ug E2/L population also had an altered stable stage distribution relative to both control populations and the F1 0.2 ug E2/L population, resulting in additional population-level alternation. These results demonstrate that continued exposure to E2 had compounding effects on sheepshead minnow populations and long-term exposures may be necessary to determine the risk EDC exposure poses to native populations