Multigenerational exposure of the estuarine sheepshead minnow (Cyprinodon variegatus) to 17β-estradiol. II. Population-level effects through two life cycles.
The evaluation of multigeneration, population-level impacts is particularly important in the risk assessment of endocrine-disrupting compounds, because adverse effects may not be evident during the first generation of exposure. Population models were developed for the sheepshead minnow (Cyprinodon variegatus) exposed to 17β-estradiol (E2) for two complete generations (F1 and F2) to determine population-level effects of multigenerational exposure to a model estrogen. Stage-structured matrix models were used to determine interactions between treatment and the number of generations exposed. Reproduction was significantly reduced in both the 0.08 and 0.2 μg E2/L treatments in both generations, and embryo and larval stages experienced reduced survival at 0.2 μg/L in the second generation only. However, increased female to male sex ratio in these treatments compensated for the loss in reproductive output, and significant population-level effects only occurred in the 0.2 μg E2/L treatment of the F2 population. The F2 population in the 0.2 μg E2/L treatment also had an altered, stable stage distribution relative to the control population of both generations and the Fl population in the 0.2 μg E2/L treatment, resulting in additional population-level effects. These results demonstrate that continued exposure to E2 had compounding effects on sheepshead minnow populations and that long-term exposures may be necessary to understand the risk that exposures to environmental estrogens pose to native populations. Although population-level effects did not occur in the Fl generation, a risk decision based on Fl organism-level effects would be protective of the population exposed for two generations.
Raimondo
Sandy
S
U.S. Environmental Protection Agency, National Health and Environmental Effects Laboratory, Gulf Ecology Division, 1 Sabine Island Drive, Gulf Breeze, Florida 32561, USA. raimondo.sandy@epa.gov
Hemmer
Becky L
BL
Goodman
Larry R
LR
Cripe
Geraldine M
GM
D000818:Animals; D052244:Endocrine Disruptors / Q000633:toxicity; D004781:Environmental Exposure; D004958:Estradiol / Q000633:toxicity*; D005260:Female; D005298:Fertility / Q000187:drug effects; D007695:Killifishes / Q000254:growth & development*; D008018:Life Cycle Stages; D008297:Male; D012098:Reproduction / Q000187:drug effects*; D018570:Risk Assessment; D012744:Sex Ratio; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D052244:Endocrine Disruptors; D014874:Water Pollutants, Chemical; D004958:Estradiol