Action
Given such concerns, EPA researchers are assessing wastewater effluents to measure their effects on ecosystems and aquatic animals while also developing innovative solutions to reduce concentrations of potential EDCs. EPA researchers are deploying a range of techniques to examine effluents from waste water treatment facilities. One fundamental approach involves chemistry-based assessments of the concentration of various known and potential endocrine-disrupting drugs or chemicals in effluents. This approach provides valuable information on the chemicals present, but is limited because methods have not been developed for measuring many chemicals of interest. In addition, mixtures of chemicals (rather than a single chemical acting alone) can have unpredictable effects on hormonal systems.
Researchers are also examining the properties of effluents using various biochemical and biological assays that describe how the effluents might affect hormonal systems. For instance, one test that assesses whether male fish have been exposed to estrogens is an assay that measures whether the gene for vitellogenin, the egg yolk protein, has been induced at levels similar levels to females or similar to a known concentration of ethynylestradiol tested in the Canadian study. Another assay under development assesses whether estrogen is turned on in human cells. Assays such as these are being used by EPA researchers to examine various types of effluents. Researchers are also studying the extent of the problem of potential EDCs in the nation's waterways. A national survey of water collected from 50 wastewater treatment plant effluents found that 13 had endocrine disruption activity, as measured by the vitellogenin gene assay in male fish. Another study took a broader approach, and showed that 5 percent of 113 samples from various California rivers and lakes had detectable endocrine disruption activity, as measured by the vitellogenin gene assay.
More comprehensive studies are now underway as these earlier studies did not test samples over different time periods or in different seasons and did not evaluate the concentrations of the various chemicals present. One current research study focuses on examining effluents on a small river in New England that has four waste treatment plants on its banks. EPA researchers along with other federal agencies (USGS, USFWS, NPS) are examining the types of chemicals in the effluents and comparing the health of fish kept in cages upstream and downstream of the treatment plants, using the vitellogenin test and other assays. Scientists are also conducting a battery of laboratory tests on the effluents, such as their effect on cells grown in the lab. Another EPA research project examines effluents from hospitals, long-term care facilities and industrial facilities to assess the composition of that wastewater. Effluents from these types of institutions may produce particularly high concentrations of EDCs - and so may represent potential targets for minimizing discharges.