If it's in your medicine cabinet, it might also be in Minnesota's lakes and streams

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news release

For release: June 2, 2015
Contact:  Alexis Donath, 651-757-2312

If it's in your medicine cabinet, it might also be in Minnesota's lakes and streams

St. Paul, Minn.— A new study released by the Minnesota Pollution Control Agency confirms that lakes and streams across Minnesota are contaminated with a variety of pharmaceuticals, ingredients from personal care products, and endocrine-disrupting compounds.  This is the latest in a series of studies investigating the presence of these chemicals in Minnesota’s surface water.

Even in remote areas of the state, the MPCA detected antibiotics, nicotine breakdown products, antidepressants, and medications for regulating diabetes, cholesterol, and blood pressure. The insect repellent DEET was found in 91% of the lakes studied. These results are consistent with previous studies of Minnesota lakes and rivers.

“We have known for some time that these compounds frequently turn up downstream from wastewater treatment plants,” said the study’s lead author, Mark Ferrey. “And recent research has shown that a surprising number are found even in remote lakes or upstream waters. But we have a lot to learn about how they end up there.”

In some water bodies, the contamination could be associated with septic systems and stormwater runoff. While it is not yet clear how these compounds are entering most remote lakes and streams, Ferrey said it is possible that these contaminants are distributed by rainfall or by atmospheric transport of dust.

The study tested 11 lakes and four streams that were previously sampled for the presence of 125 different compounds-- mostly pharmaceutical products, but also some ingredients used in cosmetics, detergents, and hygiene products. Some of the compounds were included in a previous round of testing, but the most recent report tested for many new chemicals. This study was the first in Minnesota to look for the x-ray contrast drug iopamidol, which was found in 73% of the lakes studied. Surprisingly, the highest concentration of iopamidol was found in Lake Kabetogama, located within Voyageurs National Park.

“We know more now than we have in the past about what contaminants consistently show up in surface water,” said Ferrey. “And we’re also beginning to better understand how these contaminants can affect fish and other organisms in the environment.”

Research into how these compounds might affect human health through long-term, low-level exposure is still in its early stages. The MPCA works with the Minnesota Department of Health in evaluating potential human health impacts of these chemicals. Ferrey noted that it is especially difficult to predict environmental and health effects of exposure to combinations of multiple pharmaceuticals.

Because some pharmaceutical contamination of surface water is due to wastewater, the MPCA advises that people avoid flushing unwanted medicines down the toilet. Better alternatives include taking the drugs to a medication collection site, or mixing them with vinegar or cat litter to discourage ingestion and throwing them in the trash in a sealed container. Special recommendations apply to liquid chemotherapy drugs.

The full report is available on the MPCA’s website at www.pca.state.mn.us/iryp8f4.

Broadcast version:

A new study released by the Minnesota Pollution Control Agency shows that some of Minnesota's most remote lakes and streams are contaminated with pharmaceuticals, cosmetic ingredients, and endocrine-disrupting compounds. The study found the insect repellent DEET in 91% of the lakes studied.

Lead author Mark Ferrey ("fur-RAY") noted that the study found a surprising variety of these chemicals both upstream and downstream of wastewater treatment plants. More research is needed to determine how the compounds are getting into lakes and streams, and how they might impact human health and the environment.

More information is available on the MPCA’s website


The mission of the MPCA is to protect and improve the environment and enhance human health.


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www.pca.state.mn.us • Toll-free and TDD 800-657-3864