Suburbanization, estrogen contamination, and sex ratio in wild amphibian populations.
Research on endocrine disruption in frog populations, such as shifts in sex ratios and feminization of males, has predominantly focused on agricultural pesticides. Recent evidence suggests that suburban landscapes harbor amphibian populations exhibiting similar levels of endocrine disruption; however the endocrine disrupting chemical (EDC) sources are unknown. Here, we show that sex ratios of metamorphosing frogs become increasingly female-dominated along a suburbanization gradient. We further show that suburban ponds are frequently contaminated by the classical estrogen estrone and a variety of EDCs produced by plants (phytoestrogens), and that the diversity of organic EDCs is correlated with the extent of developed land use and cultivated lawn and gardens around a pond. Our work also raises the possibility that trace-element contamination associated with human land use around suburban ponds may be contributing to the estrogenic load within suburban freshwaters and constitutes another source of estrogenic exposure for wildlife. These data suggest novel, unexplored pathways of EDC contamination in human-altered environments. In particular, we propose that vegetation changes associated with suburban neighborhoods (e.g., from forests to lawns and ornamental plants) increase the distribution of phytoestrogens in surface waters. The result of frog sex ratios varying as a function of human land use implicates a role for environmental modulation of sexual differentiation in amphibians, which are assumed to only have genetic sex determination. Overall, we show that endocrine disruption is widespread in suburban frog populations and that the causes are likely diverse.
['Lambert|Max R|MR|', 'Giller|Geoffrey S J|GS|', 'Barber|Larry B|LB|', 'Fitzgerald|Kevin C|KC|', 'Skelly|David K|DK|']
D000663:Amphibians D000818:Animals D000835:Animals, Wild D003237:Connecticut D052244:Endocrine Disruptors D004967:Estrogens D005260:Female D065928:Forests D006801:Humans D008297:Male D008675:Metamorphosis, Biological D061005:Ponds D011898:Ranidae D012744:Sex Ratio D013383:Suburban Population D014874:Water Pollutants, Chemical
landscaping estrone phytoestrogen lawn environmental sex determination