Pollutants of emerging concern and endocrine active chemicals

Studies of Minnesota’s waters show that a wide variety of unregulated chemicals, such as pharmaceuticals, fragrances, fire retardants, detergents, and insecticides, are widespread in the state’s lakes and rivers.

Some of these contaminants are hormones, or chemicals known to mimic the effects of hormones in animals and cause changes to the reproductive system or to the growth and development of an organism. These "endocrine active" chemicals (EACs) may not exhibit acute toxicity at the levels normally found in the environment, but instead negatively affect the normal functioning, growth, and reproduction of an organism at very low concentrations.

Sources of these chemicals to surface water include municipal wastewater discharges, septic systems, runoff from animal agriculture, storm water, and even rain and snow.

Although the effects of most of these chemicals on fish, wildlife, and humans are not yet completely understood, the MPCA has developed a screening method — aquatic toxicity profiles — to prioritize those that are most likely to have adverse effects on aquatic life.

Endocrine-active compounds

Some chemicals can mimic the effects of hormones in animals and cause adverse physiologic effects, such as changes to the reproductive system or to the growth and development of an organism. These chemicals are called "endocrine active" compounds (EACs). These compounds do not usually exhibit acute toxicity at the levels normally found in the environment, but instead can alter the normal functioning and growth of the exposed organism at very low concentrations.

In the last decade, national and statewide studies have revealed that many chemicals with known or suggested endocrine-disrupting potential are found in the aquatic environment. These chemicals include pharmaceuticals, personal care products, chemicals associated with wastewater effluent, and a variety of industrial compounds. Apart from the disquieting realization that wastewater chemicals and drugs are detectable in much of our surface water, there is a growing concern that even at low concentrations, chemicals, or mixtures of them, may adversely affect fish, wildlife, ecosystems and possibly human health.

    MPCA research

    New report In a large 2017 study of Minnesota’s lakes, a total of 55 of the 163 chemicals tested were found in at least one of the 50 lakes sampled for this study. Even in remote areas of the state, tests revealed chemicals such as antibiotics, nicotine breakdown products, antidepressants, and medications to regulate diabetes, cholesterol, and blood pressure. The insect repellent DEET was very frequently detected, together with the hormone estrone, several medicines, and the breakdown products of detergents. This is the second study of a random selection of 50 lakes in Minnesota. The results are consistent with those of previous studies of Minnesota lakes and rivers.

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