Prescriptions for Cleaner Waterways

By Pradnya Bhandari

Teetering on the edge of a chair, my six-year-old self roots through the medicine cabinet, pushing aside plastic orange bottles for the gems hidden behind them: my gummy vitamins. My mother immediately asks me to come down, wondering if I had accidently gotten my hand on any of the medicines. Later, I see her pouring pills down the toilet and flushing them away into oblivion.

EPA researchers are studying pharmaceuticals in wastewater to help protect the nation’s waterways. Image courtesy of U.S. Food and Drug Administration.

EPA researchers are studying pharmaceuticals in wastewater to help protect the nation’s waterways. Image courtesy of U.S. Food and Drug Administration.

I’m sure many of us have been in the same situation, left with expired, unwanted prescriptions and pouring them down the sink or flushing them away. Medications pose a threat within the household, especially homes with children, because accidental ingestion can have severe consequences. However, have you ever thought of these discarded drugs as a problem to our environment as well?

In a recently published study, Eco-directed sustainable prescribing: feasibility for reducing water contamination by drugs, EPA scientist Christian Daughton presents ways we can prevent the active ingredients of pharmaceuticals from getting into our waterways. Traditionally, approaches to addressing such water pollution have been limited to waste disposal and wastewater cleanup.

Daughton’s research examines practices that are ultimately responsible for the entry of pharmaceuticals into our waterways, practices that could be altered to reduce or prevent pollution: disposal (like my mom flushing her old medicines when I was a kid), excretion (active drug ingredients your body flushes out instead of deactivation), bathing (which releases topically applied medications and drugs excreted via sweat) or other sources.

Daughton focused his research on the metabolism (deactivation) of active pharmaceutical ingredients and how they impact the environment. He used an existing system that categorizes drugs based on water solubility and intestinal absorption. Using this data, Daughton categorized drugs according to two distinct excretion profiles: (1) drugs that are excreted largely unchanged (and therefore retain their biological activity in the environment) and (2) drugs that are extensively metabolized (transformed usually into chemicals with less activity). He then examined published data on the occurrence of each drug in municipal wastewaters to find that drugs from the second category occur with less frequency and at lower levels.

In his paper, Daughton illustrates how such excretion profiles could be used to develop a healthcare practice called “eco-directed sustainable prescribing.” Understanding how a drug is excreted could help physicians prescribe drugs at lower doses or with less potential to be excreted and reach waterways. This would help reduce pollution and lead to cleaner waters.

For more about EPA research to reduce the amount of pharmaceuticals in the environment, see:

About the Author: Pradnya Bhandari is an intern for the science communications team in EPA’s Office of Research and Development and attends the University of Maryland.

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