By Ric Jensen
Might some of the prescription drugs people regularly take end up in rivers and streams and, if so, what might be the consequences for human health and plants and animals in the environment?
This topic is receiving increased attention from scientists throughout Texas and nationally. Studies are now under way at Southern Methodist University (SMU), Baylor University, Texas Tech University, and Texas A&M University to learn more about this issue.
The basic problem is that several prominent studies suggest that low concentrations of a wide range of pharmaceuticals are being detected in surface waters in the United States and throughout the world. For example, a 2002 study by the U.S. Geological Survey showed that more than 30 pharmaceuticals were present in much of the nation’s surface water.
At the same time, research indicates that very low levels of some of these contaminants might be disturbing the endocrine systems of fish and amphibians, possibly threatening the ability of these animals to reproduce and causing other behavioral abnormalities. For example, research suggests that male fish exposed to estrogen often produce chemicals and egg yolks that are typically only generated by female fish.
The good news is that chemicals that cause changes in hormone levels do not seem to pose an immediate human health risk and are not showing up in drinking water supplies. According to Jim Davenport, leader of the water quality standards team for the Texas Commission on Environmental Quality, Texas has not yet developed regulations or standards for hormones or pharmaceuticals because national standards have yet to be established. “The issue is a concern to us, but there isn’t much we can do until we get more criteria to create standards, if they are needed,” he said.
At SMU, researcher John Easton of the Environmental Engineering Department is leading studies funded by Region 6 of the U.S. Environmental Protection Agency to identify levels of such hormones as estrogen, testosterone, and progesterone in surface waters of the North Bosque River. Later, he will compare levels of hormones from that watershed to concentrations near wastewater treatment plants in the Dallas area and will attempt to correlate pharmaceutical concentrations with land use.
“There are so many cattle in the North Bosque and they create so much waste that it seems possible that hormones produced by the dairies may build up in the region’s rivers,” he said. “We want to compare how levels of hormones in surface waters in that region compare to urbanized sites.” In addition, one of Easton’s graduate students, Adrian Dongell, was recently awarded a Texas Water Resources Institute grant to examine how well wastewater treatment plants treat and remove hormones and pharmaceuticals.
Research at Baylor University is focusing on a slightly different issue-investigating the effects of pharmaceuticals on aquatic species in streams that are often comprised largely of treated wastewater. Bryan Brooks, a researcher in the Center for Reservoir and Aquatic Systems Research, is leading efforts to examine how residuals from such commonly used drugs as steroids, cholesterol fighting beta blockers and antidepressants may be affecting the environment. Much of Brooks’ research is concentrated in the Pecan Creek watershed near Denton, because streams in that area are effluent-dominated.
“We need to determine the levels of different types of pharmaceuticals that are present in river and stream segments and then examine the risks that are posed to aquatic species,” Brooks said. “If we find that fish, amphibians, and other species are being harmed, then we need to determine if a red flag should go up that may prompt us to identify the crucial questions and learn more.”
Determining the extent to which pharmaceuticals might be present in surface and ground waters of the El Paso region is the focus of studies at Texas Tech University. Researcher Audra Morse of the Civil Engineering Department are carrying out studies for El Paso Water Utility (EPWU) that investigate the extent to which estrogens, caffeine, antibiotics and other hormones and pharmaceuticals may be present in the Rio Grande River.
“This problem may be more acute in arid regions like West Texas where streams may only flow intermittently and may be effluent-dominated,” Morse said. “These compounds are designed to cause physiological effects in humans that may result in similar changes to aquatic species in the environment.” At the same time, Morse is also working with EPWU to study if highly treated wastewaters injected underground as a supplemental source of drinking water in the El Paso region might result in elevated concentrations of these chemicals in drinking water.
At Texas A&M University, graduate student Jeffrey Ullman is beginning a research project under the direction of researchers Saqib Mukhtar of the Biological and Agricultural Engineering Department and Scott Senseman of the Soil and Crop Sciences Department. The goal of this study is to learn more about the fate and transport of hormones and endocrine disruptors that might run off from concentrated animal feeding operations (CAFOs). “One of the things we hope to learn more about is whether hormones that originate in CAFOs are still active when they reach surface waters,” Mukhtar said. “It is possible that these contaminants might be reduced by environmental processes before they reach rivers and streams.”
Scientists do not yet know the extent to which pharmaceuticals, hormones and endocrine disrupting chemicals might be present in surface waters of Texas or whether these contaminants might be adversely affecting the environment. Still, national studies suggest the issue needs to be studied, in part to better understand if there might be ramifications for aquatic species and perhaps humans.
