Public drinking water in the city of La Crosse meets federal water quality standards, according to the annual drinking water quality report released Monday.
Water utilities are required by the Environmental Protection Agency to make this report available to their customers by July 1.
The EPA regulates more than 90 drinking water contaminants under the Safe Drinking Water Act.
These contaminants range from microbes associated with fecal waste to inorganic compounds including arsenic and mercury, volatile organic compounds associated with manufacturing facilities, dry cleaners, and auto shops, and chemical byproducts formed during chlorine disinfection.
The city of La Crosse gets its drinking water from 13 wells that draw groundwater from a sand and gravel aquifer about 170 feet deep.
Some of these contaminants in the report require yearly testing. The city tested for six types of contamination byproducts formed during chlorine disinfection in 2018. None exceeded federal standards.
Testing for other contaminants get scaled back over time after consecutive years of null results.
Testing for lead, copper and inorganic contaminants occurs every three years, so there won’t be new test results until 2020.
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When the city last tested for lead in 2017, it found levels of the neurotoxin at a concentration of 2.27 parts per billion (ppb) in the third highest sample. Under current EPA regulations, that sample — the 90th percentile sample — cannot exceed 15 ppb, though the CDC maintains there is no safe level for lead in a child’s blood.
Despite the drinking water meeting federal standards, there are contaminants present in the drinking water that the EPA doesn’t regulate.
The city found hexavalent chromium, a carcinogen better known as the Erin Brockovich chemical, and several stable, widespread and long-lasting hazardous chemicals known as PFAS, or per- and polyfluoroalkyl substances, during a 2013 to 2015 round of exploratory testing meant to help the EPA decide whether to add chemicals to its list of regulated contaminants.
The city of La Crosse detected 1.6 ppb of hexavalent chromium, below the 10 ppb limit California adopted in 2015 and later revoked.
The city also detected two types of PFAS at concentrations of 140 parts per trillion (ppt) and 32 ppt in one of the city wells — twice as much as the unenforceable health advisory recommended by the EPA. PFAS has been linked to health effects including suppressed immune systems and developmental problems in infants and children.
The city voluntarily took the contaminated well offline, though it diverted the water into the river from 2016 until the end of April. Earlier this month, PFAS has been detected in a second nearby well, which has also been closed.
PFAS contamination primarily comes from wastewater emissions from manufacturing sites and from firefighting foams, which use the toxic substance’s film-forming properties to suppress fires, that seep into groundwater sources. La Crosse’s contaminated wells are located near the airport, which was used in the past as a firefighting training site.
While the federal government has not set standards limiting PFAS in drinking water, Wisconsin recently recommended setting groundwater limits for PFAS at 20 ppt. If adopted, it would join 19 other states that have set their own limits or guidelines for regulating PFAS.