Transcript 2 - Minnesota Senate

DRINKING WATER
PROTECTION
Minnesota Department of Health
Randy Ellingboe
Chris Elvrum
Groundwater and Public Health
• 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
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Minnesota’s Drinking Water Sources
Public
Water:
Surface
Water
1.3 million
73 % from
groundwater
Private
Wells
1.2 million
Public Water Supply:
Groundwater
2.7 million people
Wells in Minnesota
• 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
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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 Quality
Contaminants – naturally-occurring
& anthropogenic
• Microbiological
• Bacteria, Viruses etc.
• Chemical
• Arsenic, Nitrate, PFCs
• Radiological
• Radium
• Contaminants of Emerging Concern
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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
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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
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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
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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
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