To Flush or Not to Flush?

A NextGen Blog by Samantha Houck, Radford University 

This is the latest post to our NWNL NEXTGEN BLOG series. Since 2007, NWNL has supported watershed education with college internships and blogging opportunities. This NWNL NEXTGEN BLOG series posts student essays; sponsors a forum for our student contributors; and invites upper-level students to propose work focused on watershed values, threats and solutions.

Samantha Hooke is a recent graduate of Radford University. She graduated with a Bachelor’s Degree in Biology with a focus in Environmental Studies, a minor in Communications, and a certificate in Environmental Studies and Sustainability. Samantha has always loved the outdoors and is passionate about preserving it for future generations to enjoy. 

Imagine a stream, the cleanest and most picturesque mountain stream you’ve ever seen. Crisp and clear bubbling water teeming with life beyond your naked eye. Now, think about that stream being muted with harmful chemicals. What if you helped to put those pharmaceuticals there? When we flush old medications where do they go? They do not just disappear, but rather play a huge role in the detriment of our streams.

An ongoing issue facing microbial life in streams and urban streams is that pharmaceutical drugs such as acetaminophen, caffeine and antibiotics, as well as personal care products are infiltrating our stream water. These pharmaceutical drugs reach the water through a variety of methods, but the most common way is through improper disposal of medications, such as flushing old medications down the drain expecting them to, “just disappear.” These medications do not just disappear, but instead build up in our waterways and cause a wide array of problems for stream life. This is uniquely problematic because scientists do not yet fully understand how these drugs breakdown. 

Microbial life is critical to our streams because they are the lowest level of the ecosystem’s food web. Without microbial life, other species would struggle to survive and rapidly decline. Microbial life is made up of many organisms such as algae and bacteria. What negatively affects these organisms ultimately works its way up the food chain to larger species. Microbial life is very sensitive to change that occurs in the water. Therefore, when pharmaceuticals reach the water, microbial immediately feels the negative effects. Scientists are now discovering that the drugs that we flush have a greater impact on microbial life than we first thought. 

The research team who conducted the samples identified numerous damaging effects of pharmaceutical drugs on microbial life. The pharmaceutical drugs are negatively impacting the micro-organisms respiration and breathing rates. In addition, once entering the stream the pharmaceutical drugs become a highly resistant and harmful bacteria. As a part of studies like these, scientists are working to better understand how drugs breakdown because currently there is little understanding of the process. The research team hopes understanding the science behind drug makeup and breakdown is the first step in tackling this issue. 

Stream restoration involving reconnection of an urban waterway near Baltimore with its floodplain.
Courtesy of Paul Mayer, U.S. EPA

In March of 2012, a group of scientists through the Rosi lab measured the levels of a variety of pharmaceutical drugs in four streams near Baltimore, Maryland. They used a method of sampling to collect water samples with various levels of pharmaceuticals. Through using this method, the researchers were able to get the best picture of the types and amounts of pharmaceutical drugs that were found in the water. This procedure was done for all four of the streams that were tested. 

The researchers found that all the streams tested positive for pharmaceuticals, but the urban streams had much higher levels compared to suburban streams. Figure 1 shows the level of pharmaceuticals in all of the streams, ranging from most suburban to most urban. It was also found that urban streams had higher levels of morphine, which is a breakdown component of heroin and a possible correlation with the high drug use that occurs in Baltimore. 

Figure 1, courtesy of ESA Open Access Journal

There is no doubt that pharmaceuticals are making their way to our streams, but what can be done to curb this problem? 

These streams and others being impacted across the US are valued by many for their economical and recreational purposes. We fish and boat in some of same places that are plagued with high levels of pharmaceutical toxins. As population rates continues to rise, we are rapidly developing more urban areas. As we change, so will our environment. Educating the public on proper drug disposal and doing further scientific research on how common medications can break down is important for understanding how to repair and prevent streams from becoming waste sites.


Rosi, E. J., H. A. Bechtold, D. Snow, M. Rojas, A. J. Reisinger, and J. J. Kelly. 2018. “Urban Stream Microbial Communities Show Resistance To Pharmaceutical Exposure”. Ecosphere 9 (1). doi:10.1002/ecs2.2041.

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