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DRINKING WATER

PROTECTIONMinnesota Department of HealthRandy Ellingboe

Chris Elvrum

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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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Groundwater and Public Health

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Public

Water:

Surface

Water

1.3 million

Private

Wells

1.2 million

Minnesotas Drinking Water Sources

Public Water Supply:

Groundwater2.7 million people73 % from

groundwater

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Wells in Minnesota

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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 ofsurface water always requires a substantial amount of

treatment

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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 testingor treatment required

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Source Water ProtectionPreventing contamination by

managing potential sources in a

wells 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 wellconstruction 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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