Presentation Abstract

Detection and Fate of Environmental Estrogens in Wastewater-Impacted Surface and Groundwaters
Bruce Brownawell¹, Sharanya Reddy¹, and Charles Iden^2
1Marine Sciences Research Center,
²Department of Pharmacology, State University of New York at Stony Brook, Stony Brook, NY

As a result of numerous reports of feminized male and sexually immature fish from wastewater-impacted water bodies, there has been great interest in the environmental occurrence and fate of steroid estrogens and other contaminants that can interact strongly (e.g., ethynyl-estradiol) or weakly (e.g., several alkylphenols) with estrogen receptor sites. Prior work showed that a portion of steroid estrogens and other estrogen mimicks pass through sewage treatment plants with potentially relevant ecological exposure. Observations in groundwaters, although few, suggested that steroid estrogens were not significantly mobile in porous media environments, perhaps because of the tendency of these moderately hydrophobic chemicals to sorb to geological media. Many pharmacologically active xenobiotic compounds, including steroid estrogens, however, are excreted in human urine primarily as water-soluble glucuronide and sulfate conjugates that can dissociate later releasing the active forms. We hypothesized that under some conditions soluble estrogen conjugates could act as a source of estrogens to aquifers or to groundwater-fed streams and focused our attention on developing methods to analyze for them in environmental samples. A sensitive method to measure steroid estrogen conjugates in matrix-rich sewage influents and effluents (method detection limits ranged from 0.04 to 0.28 ng/L) has been developed using high performance liquid chromatography tandem mass spectrometry (HPLC/MS/MS) with electrospray ionization. The method employs extensive sample purification by selective extraction from an Oasis HLB solid-phase cartridge followed by separation by anion exchange chromatography. This purification scheme, combined with a stable isotope dilution approach, was used to overcome problems of matrix suppression of ionization and permitted selective and sensitive detection of 10 target conjugates. It was found that the conjugates (especially the glucuronides) are rapidly degraded in sewer pipes prior to reaching sewage treatment plants, within sewage treatment plants (that remove most of the sulfate conjugates), and in septic tanks prior to leaching into groundwater systems. Preservation of these labile compounds was ineffective with common bacterial poisons and required de-activation of extracellular enzymes that hydrolyze the conjugates.

This research project suggests that steroid estrogen conjugates are unlikely to represent a “missing” source of estrogens to receiving waters. Estrogens and xenoestrogens are typically not persistent or mobile in groundwaters. Over short distances (22 feet), however, alkylphenol ethoxylate metabolites, estrogenic fluorescent whitening agents, and free estrone and β-estradiol were mobile in an anerobic septic tank plume. Each of these compound classes, however, were rapidly (less than days) transformed in the portion of the plume that was oxidized and in contact with the water table. Reliable methods also were developed for measuring sediment/soil sorbed estrogens that involve normal phase HPLC extract purification prior to immunoaffinity extraction purification of extracts and analysis by HPLC-time-of-flight-MS. The method has been applied to sewage impacted sediments from Jamaica Bay ( New York City). Results indicate that steroid hormones (at a few ng/g) may be preserved with little degradation and that the estrogenic potency (determined with in vitro assays of extracts) of steroid hormones was very similar to that of nonylphenol in these sediments. Future work will test whether poor migration of steroid estrogens (and other xeno-estrogens) in aquifers is the result of sorption or transformation reactions.

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