drinking water protection minnesota department of health randy ellingboe chris elvrum
TRANSCRIPT
DRINKING WATER PROTECTIONMinnesota Department of Health
Randy Ellingboe
Chris Elvrum
• 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 health2
Groundwater and Public Health
Minnesota’s Drinking Water Sources
Public Water Supply: Groundwater2.7 million people
73 % from groundwater
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
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
Groundwater QualityContaminants – naturally-occurring
& anthropogenic• Microbiological
• Bacteria, Viruses etc.
• Chemical• Arsenic, Nitrate, PFCs
• Radiological • Radium
• Contaminants of Emerging Concern
6
Contaminants of Emerging Concern• 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
8
Testing Drinking WaterPublic 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
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
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