Contaminants of Emerging Concern

August 2011

pharmacist filling a prescriptionHow do the 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. Carbamazepine is a medication that is reaching Minnesota lakes and rivers. Carbamazepine (also commonly known as Tegretol ®, Carbatrol®, or Equetro®) is a widely used medication that helps control seizures. MDH developed guidance values for carbamazepine in 2011. The MDH guidance value for carbamazepine is 40 parts per billion (ppb or micrograms per liter) in drinking water. Since carbamazepine has not been found in drinking water in Minnesota, exposure from drinking water is not expected to harm Minnesotans.


  • Carbamazepine is mainly used to help people with epilepsy, bipolar disorder, and a painful nerve disorder called trigeminal neuralgia.
  • Carbamazepine has been found in Minnesota surface water. It has also been found in treated wastewater at concentrations up to 1.5 ppb. It has not been found in drinking water or groundwater. However, only a few studies in Minnesota have looked for carbamazepine in drinking water.
  • Carbamazepine concentrations in surface water and treated wastewater are below the MDH guidance value of 40 ppb. If you drink water containing up to 40 ppb of carbamazepine for up to a lifetime there is little to no health risk.
  • Carbamazepine can get into your body from taking it as medication or drinking contaminated water.
  • As a prescription drug, carbamazepine has many health benefits for people taking it. However, carbamazepine may cause unintended health effects in people. Carefully read the prescribing information or package inserts for information about potential side effects, contraindications, and drug interactions when you pick up medicines from your pharmacy.
  • People who take carbamazepine should discuss any concerns that they have about health risks with their doctor or pharmacist. You can also call the Minnesota Poison Control System at 1-800-222-1222 with any questions.
  • The best way to reduce carbamazepine in the environment is to dispose of it properly. Follow the recommendations by the Minnesota Pollution Control Agency (MPCA) for disposing unwanted medications.

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

See the Citizen's Guide to Carbamazepine for more information.

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

See Carbamazepine Toxicity Summary information used by MDH (PDF: 170KB/17 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 Carbamazepine” 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 08:11AM