By Brittany Maule, Indiana Department of Environmental Management, USA

Coffee is the most popular beverage in the world. Although tea still reigns supreme in the UK, coffee drinkers pull in a hefty 70 million cups a day. Globally, the numbers shift even higher. Americans in the US consume 400 million coffee cups per day, and about 30% of those coffee drinkers add some sort of sugar or sweetener to their drink. That’s a lot of sweet java. Where does all that caffeine and sweetener go after we’ve gotten our morning pick me up? What about all the other stuff we use every day: fragrances, soap, sunscreen, prescription and over the counter medications? The answer that is becoming more and more concrete is in our waterways.

Where does it all go?

Several studies have documented these human products, sometimes called contaminants of emerging concern, or more collectively ‘trace organic compounds’ (TOCs), in freshwater systems around the world, including the UK and the US. TOCs can include anything from caffeine, to antibiotics, to insect repellent and prescription pharmaceuticals. How do these compounds end up in waterways? The main pathway is just by people using them. For example, whenever someone uses a product or takes medicine, the compounds aren’t completely metabolized by our bodies and the excess will go down the drain to a wastewater system. Unfortunately, wastewater systems aren’t designed to filter out TOCs. As a result, we find them at small concentrations out in streams, rivers and lakes.

What do we know about TOCs?  

TOCs make up about 400,000 possible compounds, so the short answer is very little. In addition to documenting what types of compounds are in the environment, researchers have been trying to understand what effects TOCs can have on aquatic life. We know TOCs were meant to have effects on people, but what has been difficult to predict is what happens to aquatic life from swimming in a chronic mixture of man-made compounds. Work so far has shown effects on multiple types of organisms from aquatic insects, to algae and plants, to fish on important functions such as growth, reproduction and the community structure that makes up these organism populations.

One recent study adds even more complexity by revealing some chemicals don’t want to behave how we think they will. Work by Niemuth and Klaper (2015) highlights how compounds we don’t expect to act like endocrine disrupting chemicals – chemicals that have hormonal effects on organisms – could be wearing this new hat. Metformin, which is a drug prescribed to help those with Type 2 diabetes improve their sensitivity to insulin is not structurally similar to other endocrine disrupting drugs. However, Niemuth and Klaper have found that male fathead minnows exposed to metformin exhibited troubling characteristics such as reduced size, a lower ability to produce offspring, and even egg production. Essentially, the effects of TOCs in the environment are possibly even harder to predict than we thought.

What can we do about TOCs in the environment?

With more cases of chronic diseases such as diabetes, the concentrations of TOCs like metformin are probably only going to increase moving forward. Couple that with increasing population, and the outlook isn’t positive for organisms living in our waterways. The average person can make a positive impact by correctly disposing of medication and using only what they need. However, trying to understand and combat the issue of TOCs is a complicated challenge of addressing both public health and environmental safety. We will need creative solutions if can’t give up our sweet java!

Further Reading:

• Bernot, M.J., Becker, J.C., Doll, J., Lauer, T.E., 2016. A national reconnaissance of trace organic compounds (TOCs) in United States lotic ecosystems. Science of the Total Environment 572: 422-433.
• Boxall, A.B.A., et al. 2012. Pharmaceuticals and personal care products in the environment: What are the big questions? Environmental Health Perspectives 120(9): 1221-1229.
• Coffee in the UK Infographic. 2015. Available from: http://www.gcoffeepod.com/en/coffee-news/11_coffee-in-the-uk-infographic.
• Huffington Post. 2015. America’s coffee obsession: Fun facts that prove we’re hooked. Available from: http://www.huffingtonpost.com/2011/09/29/americas-coffee-obsession_n_987885.html.
• Niemuth, N.D., Klaper, R.D. 2015. Emerging wastewater contaminant metformin causes intersex and reduced fecundity in fish. Chemosphere 135: 38-45.

About Me:

I recently got my M.S. in Biology at Ball State University where I studied aquatic ecology and science communication. I currently work as Environmental Manager in the Office of Water Quality, on sampling and protecting drinking water sources in the State of Indiana. When I’m not buried in a novel I love hiking and writing about life and mischievous organisms on Eco-Troublemakers, and engaging about science on Twitter