GRANGER – Some drinking water in the Lower Valley may contain a higher concentration of nitrates than is allowed by the EPA. The Lower Yakima Valley Groundwater Advisory Committee learned at its Thursday night meeting about the consequences of such contamination.
The committee invited representatives of the United State Environmental Protection Agency to answer two questions posed by members of the committee: how was the EPA standard set and what are the health risks involved in drinking water with higher concentrations than the standard?
Presenting for the EPA Thursday night was Fredianne Gray, a drinking water specialist in the Pacific Northwest region. She presented technical information and provided members of the committee with a website address (epa.gov/iris) at which members of the public can view studies that resulted in drinking water standards.
Gray explained that standards are set to protect health.
“We look at the maximum level that serves to protect health,” she said. “The standards are only based on health, not on the cost to reach those standards.”
In the case of nitrates, infants up to six months old have the highest risk. When infants are fed formula made with water that has a high concentration of nitrates, they suffer from methemoglobinemia, or blue baby syndrome.
High levels of nitrates disrupt the ability of blood to deliver oxygen to the body. This causes hypoxia, which can result in a number of physical problems, including death.
Studies found no cases of the syndrome if the nitrate level, measured as nitrogen, was lower than 10 milligrams per liter, or 10 parts per million.
Based on those studies, the EPA set 10ppm as the standard. Gray said the standard was set in 1991 and has been reassessed twice since then.
In the most recent assessment, the EPA found studies that may indicate other problems caused by high nitrate levels, including developmental issues, thyroid problems and a potential connection with cancer. Those studies are undergoing further evaluation.
Gray also explained why the World Health Organization and Canada both appear to have a different standard than the EPA. She pointed out that the United States is measuring by total nitrogen while other health organizations measure by nitrates.
The result is that the standard in Canada is 45 milligrams per liter as nitrates, which is exactly the same as the EPA’s standard of 10 mg/l measured as nitrogen.
“If someone asks why Canada allows so much more nitrates, you now know that the standards are actually the same,” she said.
After her presentation, Gray took questions from the committee. The first question was how nitrates affect adults. Gray said that methemoglobinemia is usually not seen in adults unless they have an existing problem. She was asked why the standard is set so low.
“We regulate to protect the most vulnerable,” she said. “We don’t set the standards to what a healthy adult can take.”
A member of the audience asked if a solution to the problem would be to provide bottled water to those most at risk. Gray responded that the EPA doesn’t regulate bottled water, the FDA does, and the standards might be even lower for that water than the EPA’s standard for drinking water.
“You cannot be sure that bottled water meets these regulations,” she said. “Your tap water is tested. Some bottled water companies could not provide information on whether or not their water has contamination.”
She also said that a standard store-bought filter will not remove nitrates from drinking water. When Vern Redifer of the Yakima County Commissioner’s office asked about reverse-osmosis filters, she said those work.
Another committee member asked if the high rate of anencephaly, a birth defect in which a baby is born without parts of the brain, in the Lower Valley might be related to nitrates in the water. The EPA spokesperson could not give an official answer to the question. Jean Mendoza of the Friends of Toppenish Creek said she had seen a study in which nitrates were considered a possible factor, but no link has been proven.
Jason Sheehan of the Yakima Dairy Federation said he wanted to know who is most at risk from the contamination.
“We need to focus our efforts on helping those who are most in danger,” he said.
Sheehan said there are many levels of costs. Although the goal of the committee is to reduce nitrate contamination in all groundwater, focusing on the people who are most at risk may make more economic sense in the short term.
Other members of the committee pointed out that all materials produced so far have indicated the at-risk groups: children less than 12 months of age, pregnant women or individuals susceptible to health problems from nitrate as documented by a healthcare provider.
The health district has been conducting free testing of private wells to determine nitrate levels. Redifer said 98 on-site surveys have been completed now, and 17 came back with nitrate levels higher than EPA standards.
People who have anyone who fits the at-risk category in their household should contact the committee through the website at yakimacounty.us/gwma to find out about testing opportunities.
‑ Laura Gjovaag can be contacted at 509-837-4500, or email