Health Risk Limits Program

The Health Risk Limits team at MDH conducts reviews for contaminants that have historically been found in Minnesota groundwater. Legacy contaminants are chemicals have been detected at least once in Minnesota groundwater that are not considered contaminants of emerging concern. Contaminants are selected in partnership with state agencies for full review or rapid assessment annually.

• Full Review: in-depth contaminant review that includes a review of scientific literature, selection of critical studies that examine dosages and presentation of adverse health events, and development of a reference dose to protect for critical health effects that leads to health-based water guidance. This type of review takes months to complete.
• Rapid Assessment: screening-level guidance that is developed to be more protective than guidance values produced during a full review. Rapid assessments use a small number of well-established sources, and is not as thorough as a full review. This level of guidance takes only a few days to develop.

Health-based water guidance values can be found in the Human Health-Based Water Guidance Table.

2025 Contaminants Under Review

See Chemicals Under Review for current reviews by the Health Risk Limits Program.

• In progress:
  • Arsenic
  • Lithium
  • Pyroxasulfone and Pyroxasulfone M1
• Completed in 2025:
  • Methyl Ethyl Ketone
  • Sulfentrazone
  • Sulfentrazone 3-Carboxylic Acid
• Completed in 2024:
  • Isoxaflutole and Diketonitrile (DKN)