In the latest in a series of studies aimed at investigating the presence of chemicals in Minnesota's waterways, it was confirmed that streams and lakes across Minnesota have been contaminated by a number of endocrine-disrupting compounds, ingredients from personal care products and pharmaceuticals.
The Minnesota Pollution Control Agency released a study showing that, even in the remotest areas of the state, drugs for regulating blood pressure, cholesterol and diabetes and chemicals like antidepressants, antibiotics and nicotine byproducts have been found in waterways. In 91 percent of the lakes surveyed, DEET, an insect repellent, was detected.
These results are consistent with earlier studies involving rivers and lakes in Minnesota. Mark Ferrey, the lead author for the study, said that it has been known for a time that various compounds commonly turn up in areas downstream of wastewater treatment plants but recent research has shown that the compounds also make their way upstream.
"We have a lot to learn about how they end up there," he added.
Stormwater runoff and septic systems are some of the potential contamination sources for surface water not affected by wastewater treatment plants. Additionally, it is also possible that contaminants find their way into waterways when dust travels.
Four streams and 11 lakes were tested for the study, all of which have been sampled previously to check for the presence of 125 compounds. Most of the compounds in question are from pharmaceutical products but a number are also found in hygiene products, cosmetics and detergents.
Many of the compounds confirmed in the study were detected in tests carried out in 2008 but a lot of new chemicals were spotted as well. This was the first study to check for iopamidol, an X-ray contrast drug, in Minnesota's waterways. Iopamidol showed up in 73 percent of lakes tested and was found in the highest concentration in Voyageurs National Park's Lake Kabetogama.
It's important to research compounds in waterways because of the potential risk to health through long-term but low-level exposure. The MPCA is working with the Minnesota Department of Health to evaluate how the compounds possibly affect people. However, when multiple drugs and chemicals are present, it is more difficult to accurately predict how exactly contaminated water will affect the well-being of those in the state.
One of the ways people can help in keeping chemicals away from surface water is by properly disposing of medicines. If they can't be taken to collection sites, medicines must be sealed properly and thrown in the trash, not flushed down the toilet.
Photo: Meghan Newell | Flickr