Contaminants of Emerging Concern

September 2011

pills in bottlesHow do medications that we take turn into an environmental concern? We flush them down the toilet. Our bodies may not use all of the medication that we take. Some of it leaves our bodies through urine and feces and mixes with wastewater. Medications can also get into wastewater when we wash them down the drain or flush them down the toilet as a means of disposal. Acetaminophen is widely used to reduce fever and pain. The United States Geological Survey (USGS) and Minnesota Pollution Control Agency (MPCA) measured acetaminophen in Minnesota drinking water. They did not find acetaminophen in treated drinking water, and found it only once in untreated drinking water. MDH developed a guidance value for acetaminophen in 2011. The MDH guidance value for acetaminophen is 200 parts per billion (ppb or micrograms per liter) in drinking water. Since acetaminophen has not been found in treated drinking water in Minnesota, exposure from contaminated drinking water is not expected to harm Minnesotans.


  • Acetaminophen is a medication widely used to reduce fever and pain. It is used in many brands of non-prescription medications. It is also combined with other drugs in some prescription pain medications. High doses of acetaminophen can harm the liver.
  • Acetaminophen has been found in Minnesota surface water and wastewater. It has not been found in groundwater or treated drinking water. However, only a few studies in Minnesota have looked for acetaminophen in treated drinking water.
  • Acetaminophen concentrations found in Minnesota waters are below the lowest MDH guidance value of 200 ppb. If you drink water containing up to 200 ppb acetaminophen for up to a lifetime there is little to no health risk.
  • So far, acetaminophen was found only once in untreated drinking water at a concentration of 0.010 ppb. This is about 20,000 times lower than the MDH guidance value.
  • Most acetaminophen gets into your body from taking it as medication, not from contaminated drinking water.
  • If you are taking acetaminophen, it is important that you take the right amount. If you are taking more than one medication with acetaminophen at the same time, the total amount you are taking is the amount in each of the products added together.
  • Discuss your concerns with your doctor or pharmacist. You can also call the Minnesota Poison Control System at 1-800-222-1222 with any questions.
  • One way to reduce acetaminophen in the environment is to dispose of it properly. Follow the recommendations from the Minnesota Pollution Control Agency (MPCA) for disposing unwanted medications.

Do you want to learn more about Acetaminophen in Minnesota and how to reduce your exposure and environmental impact?

See the Citizen’s Guide to Acetaminophen for more information.

Do you need more details about the health-based guidance?

See Acetaminophen Toxicity Summary information used by MDH (PDF: 87KB/13 pages) for toxicity values used to develop the health-based guidance.

    Do you need more technical information about toxicity and exposure?

     “An Environmental and Health Professional’s Technical Guide to Acetaminophen” will be posted here and announced to our email subscriber list when available. Subscribe to our email notification service by selecting "Groundwater Rules, Guidance and Chemical Reviews."


Updated Wednesday, October 05, 2011 at 08:08AM