1. DRINKING WATER PROTECTION Minnesota Department of Health Randy Ellingboe Chris Elvrum

2. Contaminants in drinking water create potential for disease Chemicals Pathogens (bacteria, protozoans, viruses) The Good News: MN Public water supplies are doing a good job at protecting public health, and compliance with the Safe Drinking Water Act is very high (>99%) Majority of private wells provide a safe adequate supply The Bad News: Some private water supplies at risk – knowledge limited Number of potential contaminants increasing, most unregulated Pressing need to evaluate impacts on public health 2 Groundwater and Public Health

3. Minnesota’s Drinking Water Sources Public Water Supply: Groundwater 2.7 million people 73 % from groundwater

4. Wells in Minnesota 4 Public Water Supply Wells serve 2.7 million people 11,000+ Public Wells Private Wells serve 1.2 million people ~250,000 Private Wells in operation

5. GW Quality for Drinking Water Groundwater sources across the state vary widely in quality, from those sources that require no treatment to those that are much like surface water sources Surface water and groundwater under the influence of surface water always requires a substantial amount of treatment

6. Groundwater Quality Contaminants – naturally-occurring & anthropogenic Microbiological Bacteria, Viruses etc. Chemical Arsenic, Nitrate, PFCs Radiological Radium Contaminants of Emerging Concern 6

7. Society uses a lot of chemicals 42,000 chemicals + 40,000 polymers in common use Science is better at looking for and finding chemicals Looking for more chemicals in more places Better laboratory analytical tools / lower detection limits There are new ways to measure toxicity Low doses / subtle effects We have toxicity data on a limited number of chemicals Drinking water advice on a few hundred

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9. Testing Drinking Water Public Water Supplies Safe Drinking Water Act - covers100+ contaminants Frequency and number of parameters tested in finished water varies, depending on risk Private Wells Arsenic, Nitrate, and Bacteria Testing at time of well construction. No additional testing or treatment required 9

10. Source Water Protection “Preventing contamination by managing potential sources in a well’s recharge area” Required in MN rule for groundwater source systems More effective and cost-efficient than clean-up, treatment or drilling a new well * Private supplies protected by well construction code 10

11. Drinking Water Summary Essential to economic growth and development Human activities impact quantity and quality Contaminants both naturally occurring and anthropogenic Unregulated contaminants a challenge Protection is key for public health 11