Findings from Worldwide Research into Endocrine-Disrupting Substances

[Effects of synthetic estrogen ethinylestradiol on early life stages of mink frogs and green frogs in the wild and in situ; Environmental Toxicology and Chemistry], 2005; Vol. 24 (8):2027-2036

[Induction of vitellogenin mRNA in juvenile Chinese sturgeon (Acipenser sinensis Gray) treated with 17β-estradiol and 4-nonylphenol; Environmental Toxicology and Chemistry], 2005; Vol. 24 (8):1944-1950

A global decline in amphibian and sturgeon populations has prompted worldwide research into endocrine-disrupting chemicals (EDCs). EDCs and their effects on these populations are the focus of two studies—one in Canada and another in China. Findings from these studies are published in the latest issue of Environmental Toxicology and Chemistry.

Endocrine-disrupting chemicals come in the form of estrogenic contaminants. Natural and human-made estrogens have been detected in sewage treatment effluents and, occasionally, in receiving waters because of their incomplete removal in the treatment process. These chemicals have the ability to mimic the actions of endogenous estrogen, thereby disrupting the endocrine system, development and reproduction. Concern regarding the potential environmental effects of these chemicals has increased during the past decade.

The study in Canada indicates that exposure to low concentrations of an environmental estrogen disrupted hatching and gonad development of native amphibians, specifically mink and green frogs, in situ and in the wild. Estrogenic contaminants such as organochlorine pesticides contaminate the waters these frogs live in, at similar concentrations to those tested.

The study in China shows the first indication of risk of EDCs to Chinese sturgeon. Sturgeon are a relatively ancient fish and are of great commercial value. All 25 extant sturgeon species are listed as protected under the Convention on the International Trade of Endangered Species. Recently, intersexual testis-ova phenomenon was found both in shovelnose sturgeon from the Mississippi River and in Chinese sturgeon in the Yangtze River.

Endocrine-disrupting chemicals not only have adverse effects on their own, but also may combine with other environmental stressors to further affect both individuals and populations. More field-based research is needed to determine the potential risk of EDCs at environmentally relevant concentrations to wild populations.

To read the entire study about amphibians in Canada, click here: http://www.allenpress.com/pdf/entc_24_801_1944_1950.pdf

To read the entire study about Chinese sturgeon, click here: http://www.allenpress.com/pdf/entc_24_828_2027_2036.pdf

Environmental Toxicology and Chemistry is a monthly journal of the Society of Environmental Toxicology and Chemistry (SETAC). For more information, visit http://www.setac.org.