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An environmental advocacy group is concerned by unregulated contaminant levels in hundreds of Iowa water systems

While some water filters are designed to screen out potentially deadly lead, many filters and bottled water with added minerals simply improve the taste of water.
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Hundreds of utilities in Iowa detected concerning levels of contaminants in drinking water in recent years, according to the Environmental Working Group, which sets its own health standards.

Hundreds of public water systems across Iowa have concerning levels of contamination, according to an environmental advocacy group that sets its own health standards. The guidelines recommended by the Environmental Working Group are far stricter than current legal limits for drinking water, which the organization argues fall short of preventing adverse health outcomes.

More than 700 Iowa utilities found certain contaminants above the guidelines set by the Environmental Working Group for substances like trihalomethanes, byproducts of the water disinfection process. The group published the findings in the latest version of its tap water database, which compiles data for utilities across the country, making it searchable by zip code.

The Iowa data comes from the state’s Department of Natural Resources and spans testing between 2014 and 2019 for more than 1,000 utilities, which serve some 2.7 million people.

According to the database, some 692 utilities exceeded the EWG’s guidelines for nitrate in recent years, though the advocacy group’s standards for nitrate and other contaminants are multiple times stricter than the legal limits set by the U.S. Environmental Protection Agency. (EWG’s standards are based on peer-reviewed research and advisories issued by state and federal analysts).

Only a handful of Iowa utilities found levels above those federal regulatory limits: seven for radium, four for arsenic and one for selenium, according to the analysis.

But EWG senior scientist David Andrews argues the legally enforceable levels set by the EPA aren’t keeping up with the science on the risks associated with toxins that may be in Americans’ tap water.

“The EPA hasn’t set any new legal limits in over two decades. And yet during that time period, our scientific understanding of how chemicals interact with our body, which chemicals are found in the environment, it’s progressed an incredible amount,” Andrews said.

The EPA sets standards that public water systems across the country are required to meet, testing for certain chemicals in tap water and taking action when they reach certain limits. But critics have long said the rules governing whether a contaminant will be added to this list are onerous and unworkable, which they say leaves Americans potentially at risk to substances they may have no idea are in their water.

In the two decades since Congress updated the Safe Drinking Water Act, adding more requirements in order for the EPA to try to set limits, the agency has not regulated any new contaminants in drinking water.

“We’re now learning that many chemicals are impacting our health and causing harm to infants, adults, at concentrations that weren’t of concern three or four decades ago,” Andrews said. “So that’s where people should be really concerned, is there have been no updates to the system or very few updates. And we think there needs to be.”

Decades of research has documented that exposure to nitrate in drinking water well below the EPA’s current maximum contaminant level of 10 parts per million is associated with increased risks of certain cancers and developmental issues in children. Nitrate is of particular concern in Iowa, where agricultural runoff from fertilizer and manure drives contamination of private wells and public water systems small and large.

Corey McCoid, Supervisor of the DNR’s Water Supply Operations Section, says the department remains committed to public health and ensuring the state’s water meets federal standards.

“The Iowa DNR acknowledges that people may be concerned by the EWG news but wants the public to know that we are committed to public health protection,” McCoid said in a written statement. “The Iowa DNR monitors results from public water supplies daily to identify drinking water concerns of the National Primary Drinking Water Regulations and will take action as appropriate."

McCoid recommended Iowans read up on their utilities by reviewing the department's annual compliance reports and state data.

Andrews, the EWG staffer, acknowledged that the group’s stringent levels don’t factor in the feasibility and cost associated with regulating contaminants, saying the numbers are “ideal values” if human health was the only concern. But he argues that current legal standards underestimate the cost associated with not regulating, born by customers purchasing their own filters or bottled water, and patients paying for doctor’s bills from conditions that may be linked to contaminants coming from their tap.

“For too long the actual health costs and the public health benefits of reduced concentrations has been undercounted, underrepresented. We think that many of these compounds are having significant cost impacts on our health,” Andrews said.

The long-term solution isn’t more expensive filtration in the home or the processing plant, Andrews said, but better source water protection.

Kate Payne was an Iowa City-based Reporter