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Pharmaceuticals in our Water Supplies

November 08 2009

Are “Drugged Waters” a Water Quality Threat? University of Arizona - Arizona Water Resource Newsletter  July 2000 Developed to promote human health and well being, certain pharmaceuticals are now attracting attention as a potentially new class of water pollutants. Such drugs as antibiotics, anti-depressants, birth control pills, seizure medication, cancer treatments, pain killers, tranquilizers and cholesterol-lowering compounds have been detected in varied water sources. Where do they come from? Pharmaceutical industries, hospitals and other medical facilities are obvious sources, but households also contribute a significant share. People often dispose of unused medicines by flushing them down toilets, and human excreta can contain varied incompletely metabolized medicines. These drugs can pass intact through conventional sewage treatment facilities, into waterways, lakes and even aquifers. Further, discarded pharmaceuticals often end up at dumps and land fills, posing a threat to underlying groundwater. Farm animals also are a source of pharmaceuticals entering the environment, through their ingestion of hormones, antibiotics and veterinary medicines. (About 40 percent of U.S.-produced antibiotics are fed to livestock as growth enhancers.) Manure containing traces of such pharmaceuticals is spread on land and can then wash off into surface water and even percolate into groundwater. Along with pharmaceuticals, personal care products also are showing up in water. Generally these chemicals are the active ingredients or preservatives in cosmetics, toiletries or fragrances. For example, nitro musks, used as a fragrance in many cosmetics, detergents, toiletries and other personal care products, have attracted concern because of their persistence and possible adverse environmental impacts. Some countries have taken action to ban nitro musks. Also, sun screen agents have been detected in lakes and fish. Researchers Christian G. Daughton and Thomas A. Ternes reported in the December issue of “Environmental Health Perspectives” that the amount of pharmaceuticals and personal care products entering the environment annually is about equal to the amount of pesticides used each year. Concern about the water quality impacts of these chemicals first gained prominence in Europe, where for over a decade scientists have been checking lakes, streams, and groundwater for pharmaceutical contamination. American officials and scientists are taking note, with two recent U.S. professional organizations — the National Ground Water Associations and the American Chemical Society — addressing the issue at their annual meetings this summer. The issue emerged in Europe about ten years ago, when German environmental scientists found clofibric acid, a cholesterol-lowering drug, in groundwater beneath a German water treatment plant. They later found clofibric acid throughout local waters, and a further search found phenazone and fenofibrate, drugs used to regulate concentrations of lipids in the blood, and analgesics such as ibuprofen and diclofenac in groundwater under a sewage plant. Meanwhile other European researchers discovered chemotherapy drugs, antibiotics and hormones in drinking water sources. In the United States, the issue might have attracted earlier notice if officials had followed up on observations made 20 years ago. At that time, EPA scientists found that sludge from a U.S. sewage-treatment plant contained excreted aspirin, caffeine and nicotine. At the time, no significance was attached to the findings. In Phoenix about this time another event occurred that also might have alerted officials that pharmaceuticals could pose a water quality threat. Herman Bouwer of the U.S. Agricultural Research Service in Phoenix recalls that clofibric acid was found in groundwater below infiltration basins that were artificially recharging groundwater with sewage effluent. Bouwer says more attention should have been paid to the finding; if clofibric acid could pass through a sewage treatment plant and percolate into the groundwater so also could many other drugs. Europeans, however, took the lead in researching the issue. In the mid-1990s, Thomas A. Ternes, a chemist in Wiesbaden, Germany, investigated what happens to prescribed medicines after they are excreted. Ternes knew that many such drugs are prescribed, and that little was known of the environmental effects of these compounds after they are excreted. He researched the presence of drugs in sewage, treated water and rivers, and his findings surprised him. Expecting to identify a few medicinal compounds he instead found 30 of the 60 common pharmaceuticals that he surveyed. Drugs he identified included lipid-lowering drugs, antibiotics, analgesics, antiseptics, beta-blocker heart drugs, residues of drugs for controlling epilepsy as well as drugs serving as contrast agents for diagnostic X rays. Results of recent research in North America also indicate reason for concern. At the June National Groundwater Association conference, Glen R. Boyd, a Tulane University civil engineer, reported detecting drugs in the Mississippi River, Lake Ponchetrain and in Tulane’s tap water. Boyd and his team found in tested waters low levels of clofibric acid, the pain killer naproxen and the hormone estrone. Samples of Tulane’s tap water showed estrone averaging 45 parts per trillion with a high of 80 parts per trillion. At the recent American Chemical Society conference, Chris Metcalfe of Trent University in Ontario reported finding a vast array of drugs leaving Canadian sewage treatment plants, at times at higher levels than what is reported in Germany. Such drugs included anticancer agents, psychiatric drugs and anti-inflammatory compounds. North American treatment plants may show higher levels of pharmaceuticals because they often lack the technological sophistication of German facilities. The U.S.G.S. is currently conducting the first nationwide assessment of “emerging contaminants” found in selected streams, including the occurrence of human and veterinary pharmaceuticals, sex and steroidal hormones and other drugs such as antidepressants and antacids. One hundred stream sites were identified, representing a wide variety of geographical and hydrogeological settings. Four of these sites are in Arizona: Santa Cruz River at Cortaro Road; Santa Cruz River near Rio Rico; Salt River below 91st Ave. sewage treatment plant; and Gila River above diversions at Gillespie Dam.

Mapping of human genome means more drugs, possibly more pollution Pharmaceuticals are greatly increasing in numbers and kinds, with greater likelihood of releases into the environment. Before the recent announcement of the almost complete categorization of the human genome, Christian G. Daughton and Thomas A. Ternes wrote in an article that appeared in Environmental Health Perspectives, “The enormous array of pharmaceuticals will continue to diversify and grow as the human genome is mapped. Today there are about 500 distinct biochemical receptors at which drugs are targeted. ... The number of targets is expected to increase 20-fold (yielding 3,000 to 10,000 drug targets) in the near future.” The authors warn, “This explosion in new drugs will severely exacerbate our limited knowledge of drugs in the environment and possibly increase the exposure/effects risks to nontarget organisms.”

Stream sites were chosen that were expected to be highly susceptible to contamination by targeted compounds. Testing the sites will provide an initial indication of the potential for these compounds to enter the environment, as well provide an opportunity for developing suitable laboratory methods for measuring compounds in environmental samples at very low (sub-ppb) levels. Detected contaminants include caffeine, which was the highest-volume pollutant, codeine, cholesterol-lowering agents, anti-depressants, and Premarin, an estrogen replacement drug taken by about 9 million women. Also chemotherapy agents were found downstream from hospitals treating cancer patients. Final results from the study are expected to be released in the fall. For additional information about the U.S.G.S. study check the website: toxics.usgs.gov/regional/emc.html What risk does chronic exposure to trace concentrations of pharmaceuticals pose to humans or wildlife? Some scientists believe pharmaceuticals do not pose problems to humans since they occur at low concentrations in water. Other scientists say long-term and synergistic effects of pharmaceuticals and similar chemicals on humans are not known and advise caution. They are concerned that many of these drugs have the potential of interfering with hormone production. Chemicals with this effect are called endocrine disrupters and are attracting the attention of water quality experts. To some scientists the release of antibiotics into waterways is particularly worrisome. They fear the release may result in disease-causing bacteria to become immune to treatment and that drug-resistant diseases will develop. Scientists generally agree that aquatic life is most at risk, its life cycle, from birth to death, occurring within potentially drug-contaminated waters. For example, anti-depressants have been blamed for altering sperm levels and spawning patterns in marine life. Most studies of pharmaceutical and pharmaceutically active chemicals in water have mostly focused on aquatic animals. For example, recent British research suggest that estrogen, the female sex hormone, is primarily responsible for deforming reproductive systems of fish, noting that blood plasma from male trout living below sewage treatment plants had the female egg protein vitellogenin. This finding would seem to be consistent with what U.S. researchers suspect has occurred downstream from treatment plants in Las Vegas and Minneapolis. Carp in these areas show the same effects as the British fish. Some scientists believe arid regions of the West are especially vulnerable to the effects of drug-contaminated effluent. These areas are more likely to have streams that rely almost entirely on effluent for flow, especially during dry months. Further, effluent is extensively used in irrigation and even for recharging drinking water aquifers. Also, areas of the West have attracted large number of retired people who are likely to use more pharmaceuticals than other population segments; thus more pharmaceuticals in wastewater. Endocrine Disrupters in Water What Are EDs? What Risks Do They Pose? Endocrine disrupters (EDs), a relatively new term in the water quality glossary, is the focus of much recent discussion and debate. What are EDs, and what are their water quality implications? ED is a self-defining term; i.e. EDs are compounds that disrupt the endocrine system. The endocrine system consists of various glands that regulate the functioning of all organ systems. Since the endocrine system is involved in such critical functions as basic metabolism and reproduction, even slight interferences with endocrine functions, especially during certain phases of the life cycle, can cause profoundly damaging effects. EDs represent a broad array of compounds of varied origins and could include natural hormones; various pharmaceuticals including birth control pills; and estrogen replacement products and other steroids. Many of these compounds are taken by humans, excreted and released with wastewater or effluent. Pesticides and various industrial chemicals like dioxin and PCBs also are sources of EDs that often end up in water bodies. While not hormones themselves, they are hormonal active agents. Concentrations of EDs are likely to be extremely small, occurring at times in nanograms per liter. On a temporal scale this is equivalent to about one second in 31 years. Yet, one nanogram per liter of a typical pharmaceutical is equivalent to about two trillion molecules per liter. This represents a rather large quantity to bind with receptors in the human or animal body. Resistant to chemical and biological degradation, endocrine disrupting chemicals appear to persist in the environment and to bioaccumulate. EDs are distributed worldwide, and virtually all living organisms are directly or indirectly exposed to them, through ingesting contaminated foods or waters, breathing contaminated air, or merely through contact with contaminated soils, sediments or water. Much of the concern about the potential hazards of EDs can be traced to the development in 1938 of a man- made estrogen, called diethylstilbestrol or DES. Hailed at the time as a miracle drug, DES essentially mimics the action of sex hormones in the body. Its many uses at the time included treating women to prevent miscarriages. Later it was found that some daughters of women having taken DES during pregnancy developed a rare tumor of the vagina. Scientists have since observed certain populations of wildlife with symptoms of exposure to environmental contaminants that affect the endocrine system; e.g. feminized fish that were exposed to municipal and industrial effluent and alligators with delayed or abnormal sexual differentiation from central Florida lakes contaminated with organochlorine pesticides. Questions also have been raised about whether EDs are the cause of the documented general decrease in human semen quality and increased breast cancer in woman. “Our Stolen Future,” a book published in 1996, attracted public attention to the issue. In the tradition of “The Silent Spring,” “Our Stolen Future,” written by Theo Colborn, Dianne Dumanoski and John Peterson Myers, warned of an impending crisis, reporting that synthetic chemicals are now pervasive in the environment. By mimicking natural hormones these chemical disrupt the normal reproductive and development process and pose a serious threat to future generations of people and wildlife. A general consensus among most scientists, however, is that the data is insufficient to determine the ecological or human health risks posed by EDs. Yet sufficient evidence exists to raise concerns and warrant further study, and government action is underway. Within the EPA Office of Research and Development Strategic Plan, ED research is identified as one of the six high-priority topics. The agency has developed a comprehensive ED research plan. Further, in response to mandates of the 1996 Food Quality and Protection Act and the Safe Drinking Water Act, EPA is developing an ED screening program, with notice of the final program expected in Dec. 2001. This final policy statement will describe the screens and tests to be required as part of the program, as well as the chemicals to be included and the priority-setting procedure for determining the order of testing. In response to requests from various federal entities, the National Research Council studied the ED issue and published a report last year. In its report the NRC committee avoided the term endocrine disrupters because it “is fraught with emotional overtones and [is] tantamount to a prejudgement of potential outcomes.” They substituted the term “hormonally active agent” or HAA as a more neutral term, “defined as an agent that has demonstrated hormone-like activity in a test system.”

Book Finds Reasons for Concern Because the endocrine disruption question has surfaced so recently, the scientific case on the extent of the threat is still far from complete. Nevertheless, if one looks broadly at a wide array of existing studies from various branches of science and medicine, the weight of the evidence indicates that humans are in jeopardy and are perhaps already affected in major ways. Taken together, the pieces of this scientific patchwork quilt have, despite admitted gaps, a cumulative power that is compelling and urgent. (from Our Stolen Future, by Colborn, Dumanoski and Myers)

After reviewing existing scientific knowledge, the NRC Committee on HAAs in the Environment decided that more information is needed before HAAs potential to harm developing organisms can be understood. The report views as inconclusive current evidence showing that harmful ecological and health effects can result from exposure to certain chemicals, stating that such evidence does not clearly demonstrate whether hormonal properties caused the observed effects or whether some other toxicological agent was the cause. The NRC report recommended various research areas to study exposure to HAAs. These include long-term monitoring of known HAAs; study of human and other biota intake of phytoestrogens and synthetic HAAs; and identification of primary exposure sources. The report also recommended study of primary routes of exposure, e.g., diet and drinking water, to determine typical baseline intake levels. Others argue that sufficient ecological evidence exists to demonstrate the hazards of EDs and to justify action. They say that protecting public health in the real world involves more than a commitment to the scientific ideals of strict cause-and effect proof that may be more appropriate to controlled laboratory experiments. They call for examining information from a variety of sources including wildlife data, laboratory studies and research on the mechanism of hormone action or toxicity. They say weighing such evidence would demonstrate the need for more immediate action.