University of California Water Resources Center

Pharamceutically active compounds (PhACs) are a group of compounds that include hormones, antibiotics and painkillers. Results of several recent studies suggest that these compounds are present in wastewater effluents and in polluted surface waters. The possible presence of these compounds is especially significant to populated arid regions where wastewater effluents are used as drinking water and to augment freshwater habitats. To assess implications of PhACs in polluted waters, we have studied the fate and transport of several hormones. In the initial phase of the investigation, new analytical techniques were developed that are capable of detecting the hormones 17~-estradiol, ethinyl estradiol and testosterone under the conditions encountered in polluted natural waters. Analysis of hormones in wastewater effluents from conventional treatment plants indicates that estrogenic hormones are present at concentrations comparable to those that cause endocrine disruption in fish under laboratory conditions. Testosterone is also present at similar concentrations, but no data are available on the threshold concentrations for endocrine disruption in fish. Hormones were detected at slightly lower concentrations in surface water samples, indicating that some removal may occur. Laboratory studies of hormone partitioning suggest that sorption is a relatively unimportant removal mechanism in surface waters. However, most hormones should be removed by adsorption during wastewater treatment. Additional research is needed to assess the mechanism through which hormones pass through wastewater treatment plants as well as their transformation in the aquatic environment.