Local Water Systems Exceed Radium Standard
Tests on 957 community water supply systems during the past year have again shown little evidence of contamination problems in Minnesota, according to the Minnesota Department of Health (MDH).
Test results for calendar year 2008 are summarized in the newly released edition of the department’s report on the state of Minnesota’s drinking water. MDH has published the report annually since 1995.
Minnesota’s public water supply systems are tested on a regular basis for bacteria, nitrate and other inorganic chemicals, radiological elements, and up to 118 different industrial chemicals and pesticides. The MDH annual report is based on the results of monitoring under the federal Safe Drinking Water Act for the past year.
The drinking water annual report includes test results for 726 city water systems throughout the state. Also included were 231 non-municipal systems that provide drinking water to people in their place of residence—in locations such as manufactured home parks, apartment buildings, housing subdivisions, colleges, hospitals, prisons, and child care facilities.
In addition to contaminants regulated by the federal Safe Drinking Water Act, MDH performs sampling of water for other substances that may be of concern.
In 2008, the Minnesota Department of Health began working with the Minnesota Pollution Control Agency (MPCA) to sample groundwater, soil, and public water systems in the state for perfluorochemicals (PFCs) that result from the use of Class B firefighting foam, which are used for petroleum fires that threaten public health and safety.
Perfluorochemicals, a family of manmade chemicals that have been used for decades to make products that resist heat, oil, stains, grease and water, may be toxic to the liver and thyroid gland and may also affect fetal and neonatal development. MDH has developed health-based exposure limits, the level considered safe for people to drink over a lifetime, for three PFCs.
The testing was performed in February and March of 2009. Many of the cities sampled showed no detections of PFCs while some of them had samples showing only trace amounts at some of their wells (in the range of 20 to 40 parts per trillion, approximately 1/10th of the health-based exposure limit). Often, the water in the wells with trace amounts is blended with water from other wells which are completely free of PFCs, diluting the trace amounts further before the water is delivered to people’s homes.
Among the other findings in the report:
- No systems exceeded current federal or state standards for pesticides or industrial contaminants. Water samples from those systems were subjected to more than 23,000 separate tests for more than 100 potential contaminants.
- Detectable levels of coliform bacteria were found in 14 community water systems, including eight municipal systems. While not all coliform bacteria cause illness, they provide an indicator of possible contamination in the system. Systems with coliform problems are routinely disinfected, flushed, and retested to ensure that the contamination is gone before being returned to normal service. The process typically takes less than a week. All but one of the affected systems served fewer than 1,000 people. The municipal systems that tested positive for bacterial contamination were Cleveland, Dalton, Dumont, Floodwood, Kasota, Lake City, Milan, and Otsego.
- While several cities in Minnesota continue to wrestle with arsenic in their groundwater, the vast majority of municipal drinking water systems in the state report few problems. By the end of 2008, 13 community water systems, including nine municipal systems, still exceeded the standard for arsenic. The affected municipal systems are Buffalo Lake, Dalton, Dilworth, Dumont, Elizabeth, Lake Lillian, McIntosh, Norcross, and Stewart.
- Nineteen community water systems—including 17 municipal systems—exceeded the standard for radium 226 and 228 at the end of 2008.
The affected municipal systems are Anoka, Brook Park, Claremont, East Bethel, Glenville, Goodview, Hinckley, Isanti, LaCrescent, Lewiston, Lonsdale, Medford, Pipestone, Rushford Village, St. Louis Park, Spring Lake Park, and Watson. No restrictions were placed on water consumption although residents were notified of the situation. Residents were told that this was not an emergency situation and were advised to consult with their doctors if they have any special concerns. Each of these systems has either started to make infrastructure changes or is studying alternatives to meet the maximum contaminant level.
Water systems that exceed the standards for a contaminant take corrective actions to remedy the problem; the actions include notifying their residents regarding the situation.
The positive findings in this year’s report were not unexpected, according to Minnesota Health Commissioner Dr. Sanne Magnan. “Obviously, we’re very pleased about what these test results are telling us,” she said. “The overall quality of our drinking water has been – and continues to be – excellent.”
Protecting the safety of drinking water is a continuing challenge, noted Assistant Commissioner for Health Protection John Linc Stine. “It requires the efforts of dedicated professionals at the state health department and in communities all across the state. It requires an extensive, well-maintained physical infrastructure. That’s important for protecting and maintaining the overall health of all Minnesotans.”
MDH first began publishing the annual drinking water report in 1995. The 2008 report and those from previous years are available online at www.health.state.mn.us/divs/eh/water/com/dwar/index.html.