TWIN FALLS — Twin Falls, Cassia and Minidoka counties have the highest levels of groundwater nitrate concentrations in the Magic Valley.
According to a new report from the Idaho Conservation League, for the third straight year, the area is seeing evidence of poor water quality and elevated levels of nitrogen and phosphorus.
Groundwater here comes from the Eastern Snake Plain Aquifer, which provides drinking water for more than 300,000 Idahoans and holds as much water as Lake Erie, wrote the ICL.
“The bottom line, the punchline of the report is that we continue to see degraded groundwater quality in the Magic Valley,” said Josh Johnson, a conservation associate with ICL. “So not a wildly different conclusion than we have had the first two groundwater reports, but we essentially just have increased confidence in that conclusion.”
The report combines data collected by different agencies, including the Idaho Department of Environmental Quality, Idaho Department of Water Resources and Idaho Department of Agriculture.
Almost 20% of public water systems in the Magic Valley have an average nitrate concentration above 5 mg/L, according to the report.
The maximum contaminant level for nitrate is 10 mg/L, determined by the Safe Drinking Water Act.
“That 10 mg/L number does not mean your water is safe if it’s below that,” he said. “Any elevated concentration especially above 5 mg/L would be cause for concern just in terms of long-term effects.”
The national standard was created in the 1960s in response to a condition called “Blue Baby Syndrome.” High levels of nitrate in drinking water can cause infants to suffer from a lack of oxygen. Nitrate impacts the ability of red blood cells to carry oxygen around the body.
Recent research has started to find adverse health effects after long-term exposure at smaller doses, Johnson said. In an ideal world, agencies would reevaluate that standard and focus on chronic ingestion but that has not yet happened.
Nitrate and phosphorus pollution can be tied back to agriculture and the overapplication of fertilizer. The 469,000 dairy cows in the Magic Valley produce as much nitrate as waste produced by a city of 16 million people, the report said.
Solutions to the problem do exist. The report lists six recommendations including using federal funding to incentivize farmers to adopt the best manure management and agricultural practices.
“We recognize that making some of these improvements are costly and we want to work with agriculture to address these issues,” Johnson said.
More public awareness is also needed. This kind of pollution is called nutrient pollution which is a misleading term, he said. Fertilizers are useful when growing crops but they are a pollutant when they are found in excess amounts.
It is easier to understand that cyanide or arsenic is poisonous because any amount is toxic in water, he said. Nitrogen and phosphorus can be harder to acknowledge because they are beneficial for agriculture.
“In this case, it’s not toxic in the same way but certainly has those health effects,” Johnson said.
The report also calls for better monitoring in the Magic Valley and pairing groundwater data with demographic information.
“First and foremost, Idahoans deserve to know what is in their drinking water and if their health is at risk,” the report says.