©2016 Mahoning Valley Water Inc.  Pharmaceuticals In Drinking Water Supplies      So what do you do with old, unused prescription medications?  Probably what you’ve always done, you flush them down the toilet.  Guess where they end up...our drinking water!      According to a recent article in Water Conditioning & Purification by Dr. Kelly Reynolds, research scientist at the University of Arizona, scientists are becoming increasingly concerned about the potential public health impact of environmental contaminants originating from industrial, agricultural, medical and household practices.  A variety of pharmaceuticals including painkillers, tranquilizers, antibiotics, birth control pills, estrogen replacement therapies, chemotherapy agents, etc. are finding their way into the environment through human and animal waste, and landfill leaching.   40 % of antibiotics manufactured are fed to livestock as growth enhancers.  Manure, containing trace amounts of pharmaceuticals, is spread on land as fertilizers from which it can leach into local streams and rivers.      The prevalence of pharmaceuticals in water is nothing new; what is new is our ability to detect trace amounts.  The topic first gained notice in the early 1990’s when European scientists found clofibric acid (a cholesterol-lowering drug) in groundwater.  During 1999-2000, the U.S. Geological Survey conducted the first nationwide investigation of the occurrence of pharmaceuticals, hormones and other organic contaminants in 139 streams from 30 states.  A total of 95 contaminants were targeted including antibiotics, prescription and non-prescription drugs, steroids and hormones.   Even though the test sites were chosen based on their increased susceptibility to contamination from urban or agricultural activities , a surprising 80 percent of streams sampled were positive for one or more contaminant.  Furthermore, 75 percent contained two or more contaminants, 54 percent had greater than five, 34 percent had more than ten, and a whopping 13 percent had more than 20 contaminants.  82 contaminants were found in at least one sample.      Pharmaceuticals have been found in treated sewage effluents, surface waters, soil and tap water, though at very low levels (parts per trillion)  These levels are far below recommended prescription dose and are supposed to be unable to induce acute effects in humans, however, they have been found to affect aquatic ecosystems.  To date, most attention has been focused on hormone disruption in fish due to estrogens present and the rise of bacterial pathogens resistant to conventional antibiotic treatment due, in part, to their exposure to sub-lethal levels of antibiotics in their environment.  Antibiotics and estrogen are thought to persist either because they don’t biodegrade or because we just keep adding more and more to the environment.   Other studies have shown that antidepressants trigger premature spawning in shellfish while drugs that treat heart ailments block the ability of fish to repair damaged fins.  The suspicion with humans is that the very low levels of contaminants found would not likely produce acute, noticeable effects but rather subtle impacts such as behavior or reproductive effects that could very well go unnoticed and that health threats will probably be long term and not imminent.      There are tens of thousands of man-made and naturally occurring chemicals listed as possible environmental pollutants.  It would be an overwhelming task to monitor all but a handful.  The good news is removal methods designed for elimination of one contaminant are likely to be effective for many other similar contaminants.  The bad news is  conventional water and wastewater treatment methods allow many classes of pharmaceuticals to pass through unchanged.      So far, oxidation of pharmaceuticals during conventional ozonation has proven effective where relatively low doses of ozone were capable of complete transformation of the select pharmaceuticals tested.  Certain pharmaceutical compounds are effectively removed by additional, advanced oxidation processes such as ozone and ultraviolet, or ozone and hydrogen peroxide.   In addition, membrane filtration and filtration with granular activated carbon are thought to be highly effective.  Nanofiltration and reverse osmosis eliminated all drugs tested.  Chlorine, the most popular drinking water disinfectant used in the United States, was less effective than ozone.      Although use of advanced water treatment technologies could greatly reduce the risks of pharmaceutical exposures via drinking water, certain pharmaceuticals have been found to be especially recalcitrant.  In addition, toxic metabolites may be created following oxidation procedures.      So, what is the true risk assessment of pharmaceuticals and the like in water?  Do they present a health threat to humans and/or wildlife exposed?  The truth is, no one knows.  Some scientists believe the exposure levels are so low they’re ineffective.  Others are concerned about long-term, chronic and combined exposures to agents designed to cause a physiological effect in humans.  Many more scientists agree we should be concerned about aquatic ecosystems where sperm levels and spawning patterns in aquatic organisms have been clearly altered in environments heavily polluted with a class of hormone-altering pharmaceuticals known as endocrine disrupters.      With a growing and aging population as well as increased reliance on drug treatments, and development of new drugs, the problem with pharmaceutical contamination promises to also increase.  Drugs are obviously necessary for the health and well being of individuals, not to mention the optimization of livestock development.  So, how do we begin to control environmental contamination?      Source control aimed at medical disposal practices may be an effective first step.  Designing more environmentally friendly chemicals, minimizing overuse and misuse of drugs, and point-of-use treatment are all potential control approaches worth exploring should scientists determine a significant risk. 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