Studies show chemicals detected in lakes and rivers
Two studies released by the Minnesota Pollution Control Agency (MPCA) confirm that a wide variety of unregulated chemicals are ending up in Minnesota's lakes and rivers.
The chemicals, including pharmaceuticals and personal care products, are of concern because many have properties that can interfere with the functioning of hormones in animals and people.
In the two studies, the MPCA in 2010 and 2012 sampled lakes and rivers using funds from the state of Minnesota and the U.S. Environmental Protection Agency, part of nationwide EPA surveys to find out what's in the nation's waters.
For the lakes study, 50 lakes were randomly selected across Minnesota. Samples were collected and analyzed for 125 chemicals. The study included analysis of endocrine-active compounds (EACs) that mimic or interfere with the actions of naturally occurring hormones. These chemicals can have adverse effects on aquatic ecosystems and fish.
The insect repellent DEET was found in 76 percent of the lakes sampled. Chemicals not previously analyzed, including cocaine, the antidepressant amitriptyline and the veterinary antibiotic carbadox, were also often detected in the lakes.
The rivers study analyzed 18 chemicals, including several pharmaceuticals and personal care products, and was conducted at 150 river locations selected at random.
Parabens, a family of chemicals used as preservatives for food and cosmetics, were commonly found. Methylparaben, a breakdown product of benzotriazole, carbamazepine and several antidepressants were also found.
Many of the chemicals in the MPCA studies were detected at very small concentrations, in the low parts per trillion. Such levels are of concern because EACs have the potential to adversely affect fish and other aquatic organisms even at extremely low levels.
One part per trillion is roughly equivalent to one drop in a pool of water covering the area of a football field 43 feet deep.
The MPCA plans to continue testing surface waters for pharmaceuticals and EACs on a rotating five-year basis to identify any trends that may be occurring.
Reports on the studies and summary information are available at www.pca.