Academic journal article Environmental Health Perspectives

Estrogens from Sewage in Coastal Marine Environments. (Research)

Academic journal article Environmental Health Perspectives

Estrogens from Sewage in Coastal Marine Environments. (Research)

Article excerpt

Estrogens are ancient molecules that act as hormones in vertebrates and are biologically active in diverse animal phyla. Sewage contains natural and synthetic estrogens that are detectable in streams, rivers, and lakes. There are no studies reporting the distribution of steroidal estrogens in marine environments. We measured estrogens in sewage, injection-well water, and coastal tropical and offshore tropical water in the Pacific Ocean, western Atlantic Ocean, and Caribbean Sea. Concentrations of unconjugated estrone ranged from undetectable (< 40 pg/L) in the open ocean to nearly 2,000 pg/L in Key West, Florida, and Rehoboth Bay, Delaware (USA); estrone concentrations were highest near sources of sewage. Enzymatic hydrolysis of steroid conjugates in seawater samples indicated that polar conjugates comprise one-half to two-thirds of "total estrone" (unconjugated plus conjugated) in Hawaiian coastal samples. Adsorption to basalt gravel and carbonate sand was less than 20% per week and indicates that estrogens can easily leach into the marine environment from septic fields and high-estrogen groundwater. Of 20 sites (n = 129 samples), the mean values from 12 sites were above the threshold concentration for uptake into coral, indicating that there is a net uptake of anthropogenic steroidal estrogen into these environments, with unknown impacts. Key words: effluent, environmental, estrogen, estrone, marine, radioimmunoassay, sewage.

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Estrogens are ancient molecules that occur across diverse animal phyla (1). In vertebrates, estrogens promote cellular hydration and proliferation by modulating gene expression through the action of specific nuclear receptors. Vertebrates synthesize estrogens from androgen precursors and generally excrete estrogens in the form of polar conjugates such as sulfonates and glucuronides, which have greatly increased solubility in water.

Considerably less is known about estrogen action and metabolism in invertebrates. Scleractinian corals can take up estrogens from the water column at concentrations as low as 300 pg/L (2). Laboratory experiments with sponges, crustaceans, mollusks, and echinoderms have demonstrated that estrogens can have diverse effects, including stimulated ovarian and/or oocyte development (3-5), blocked embryonic development (6), altered enzymatic activities (7,8), accumulation of proteins (9,10), and cellular damage or apoptosis (10,11). These experiments were conducted using a wide range of experimental conditions, estrogen forms, and concentrations. It is not known, however, whether steroidal estrogens of sewage origin released into the marine environment affect growth, development, or reproduction of invertebrates, which help to form the foundation of marine food webs and ecosystems.

Sewage is known to contain natural and synthetic estrogens; however, few studies have quantified steroidal estrogens in natural fresh waters (12-15), and except during a mass coral spawn (16), estrogens have not been measured in seawater. Because estrogens are pervasive in the environment and are resistant to bacterial degradation (17), human sewage is a likely source of estrogens to coastal marine systems, with potential physiologic or ecologic effects on coastal marine organisms. Although exposure to relatively dilute estrogens in water appears not to pose a direct threat to human health (12), little is known of the residence times, adsorption properties, concentrations, or distributions of estrogens in the environment, especially in coastal marine environments. The distribution of estrogens could alter functioning of nearshore ecosystems. For example, it has been suggested that reproduction and recruitment of corals diminish near human population centers (18,19).

Synthetic estrogens, primarily in the form of birth control pills and estrogen replacement therapies, are among the most prescribed pharmaceuticals in the United States (20). Estrogen-mimicking compounds are increasingly considered environmental pollutants that disrupt basic physiologic functions in vertebrates, ranging from reduced testicular size or spermatogenesis and production of vitellogenin in males to skewed sex determination, poor development, and overall reduction in population growth (21-24). …

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