Drugs in Our Drinking Water: An Update

by Renee Cho | November 9, 2010

The 2008 Associated Press report that drugs had been found in the drinking water supplies of 41 million Americans was alarming. AP’s investigation turned up antibiotics, anticonvulsants, mood stabilizers, sex hormones, anti-anxiety drugs, acetaminophen and ibuprofen in trace amounts of parts per billion or trillion. Many people did not realize that the unused pills dumped into toilets, and medications excreted through our urine, could end up in our water supply. While sewage is treated before it’s released into reservoirs or rivers, most wastewater treatment does not remove pharmaceuticals.

Pharmaceuticals are continuously entering our waterways. Though the concentration of active pharmaceutical ingredients (APIs) is so low they were not routinely measurable even a decade ago, today’s technology can easily detect one part per trillion, (equivalent in time to one second in 33,000 years). But just because we can detect pharmaceuticals, does that mean they’re harmful to us?

Although there are no state or federal mandatory testing or reporting requirements for pharmaceutical and personal care product compounds, since 2008, municipalities such as NYC, Fairfax, Virginia, and Tampa, Florida have tested their water for pharmaceuticals and concluded that it poses no risk to human health.

Much of the testing of APIs has been done using the therapeutic dose as a baseline, with the assumption that amounts below it are inconsequential. And most APIs occur at dosages so low that an enormous amount of water would need to be ingested to reach even a fraction of a single recommended dose.

There is no such thing as pure water, according to Dr. Christian Daughton, Chief of the Environmental Chemistry Branch of the Environmental Protection Agency’s (EPA) National Exposure Research Laboratory. In a book just released by the American Chemical Society, he reports that of the 1,200 APIs commonly used today, only a few are detectable in drinking water after it’s been treated, though traditional wastewater treatment systems are not designed to deal with APIs. The six APIs found in the highest concentration are: ibuprofen, triclosan (anti-bacterial used in deodorant, toothpaste), carbamazepine (anti-convulsant and mood stabilizer), phenazone (painkiller and anti-fever drug), clofibric acid (herbicide), and acetaminophen. Only ibuprofen exceeded one part per billion.

Daughton’s concern is that even at very low dosages, there is always some effect because drugs are designed to produce biological effects at low levels. AP reported that small amounts of medication affected human embryonic kidney cells, human blood cells and human breast cancer cells. Other effects may not be detectable, but even low doses could lead to subtle changes over the long term. Only a few studies of APIs have looked at their possible impact on epigenetics (switches that affect gene expression and are sensitive to environmental influences) that could produce delayed onset effects. There are also questions about the side effects of APIs, and the risks of ingesting through drinking water APIs that were meant for external use. Another big unknown is the effect of chronic exposure to a mixed cocktail of APIs. And few tests have studied how APIs affect fetuses, children, pregnant women or those with compromised immunity. There is still not enough data to address all these concerns, but scientists are working on them and deciding how to prioritize which pharmaceuticals need more study.

Studies of API impacts on aquatic life may also have implications for human health. Fish and humans share approximately 65–75 percent of genetic similarities at over a thousand different drug receptors (tissue components that react with drugs), which is why fish are commonly used in the early development and safety testing of pharmaceuticals. One aquatic study of APIs found that male fish in streams containing antidepressants demonstrated less territorial aggression when an intruder appeared. Other studies found that synthetic estrogen produced hermaphroditic fish with reduced fertility and inhibited testicular growth in trout.

Dr. Bryan Brooks, an associate professor at Baylor University specializing in environmental toxicology and aquatic ecology, told me, “I am not as concerned about human health as I am about aquatic life—for humans, the risks are better than driving my car to work. But the risks to fish are much higher, and we are using fish as environmental sentinels as indicators of potential human health effects.”

EPA is currently analyzing the effects of pharmaceuticals and personal care products on fish in 120 urban rivers, researching whether very low levels of pharmaceuticals in water might present a risk to human health, and evaluating the development of water quality criteria for some pharmaceuticals.

Drugs use and pharmaceuticals in our water will increase with our growing population, aging baby boomers, and new uses for drugs and cosmetics. And in a future affected by climate change, more and more water will need to be recycled. So what is the answer? Bottled water? Recent studies found APIs and estrogenic chemicals present in bottled water. More sophisticated wastewater treatment? While some new technologies such as ozonation, UV and reverse osmosis can eliminate APIs, they are expensive, energy intensive and leave contaminated waste that must go to a landfill or a brine stream that’s discharged.

What’s needed is a holistic cost-benefit evaluation of the entire system that includes ways to reduce the APIs entering the water through greener chemistry, better water treatment, regulation of discharges, a change in the over prescribing practice of healthcare professionals, and more responsible consumer behavior.

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