Environmental group questions safety of federal drinking water contamination levels

The Environmental Working Group, a nonprofit analyzing water quality issues, collected research from Europe showing that maximum U.S. federal levels for nitrate can still lead to cancers. 

The federal nitrate level set by the Environmental Protection Agency is outdated, said scientist Tasha Stoiber with the Environmental Working Group. It can lead to health risks such as colorectal, ovarian, thyroid, kidney and bladder cancer.

The EPA started enforcing maximum federal levels for nitrate at 10 milligrams per liter (approximately equivalent to 10 parts per million) in 1992 to protect against blue baby syndrome. That’s still the maximum standard.

But the Environmental Working Group suggests that a maximum level of 0.14 milligrams per liter would eliminate many more cases of cancer that nitrate could currently be causing.

“We want to uncover where are there areas where there’s just not adequate protection,” Stoiber said. “We have these high levels of nitrates in certain areas, and the 10 parts per million, that’s not going to cut it.”

Nitrate is one of the most common contaminants in drinking water. It can come from the runoff or leakage of agricultural discharge, fertilized soil and septic systems into groundwater sources — which is where most New Mexicans get their water.

The chemical is especially harmful to infants and pregnant people. It can cause methemoglobinemia, also known as blue baby syndrome, and has been linked to causing cancer in animals and humans.

It’s a colorless, odorless and tasteless chemical so in order to find it, it must be tested.

It’s up to New Mexico cities and counties to stay below federal limits of the chemical, which they’re largely doing — only 14 water systems out of New Mexico’s total 386 with drinking water violations have to do with nitrate, and only six of those 14 systems have what the EPA considers severe violations.

Decades-long process to lower national levels

Lowering the national maximum nitrate levels allowed in water would be a years-long process, Stoiber said. Federal reviews could take around five years and action could take decades, she remarked.

“People should ask: ‘Why does this take so long?’ We don’t feel like this is adequately protective of health,” Stoiber said.

Changes could potentially be made through the EPA’s six-year review of national primary drinking water regulations. 

The agency collects new information on health effects of chemicals that could cause regulatory changes “that will improve or strengthen public health protection,” EPA spokesperson Melissa Sullivan wrote via email.

The review started in 2017 and results should be released in early 2023. However, nitrate has never been changed in these reviews since first results were released in 2003.

Stoiber doesn’t expect the federal government to change maximum nitrate levels in the future. She said states do have the ability to set more restrictive levels than the national level, though she isn’t aware of any that have done so, including New Mexico.

Nitrate in New Mexico

Millions across the country would be impacted if the Environmental Working Group had its way and changed the recommended max of nitrate in drinking water from the current federal limit of 10 milligrams per liter to 0.14 milligrams per liter. 

In New Mexico, 355 utilities serving almost 1.7 million people were above the Environmental Working Group’s recommended max for nitrate and nitrite (similar to nitrate but more toxic) in March 2021.

The group estimates that almost 13,000 cases of cancer per year in the state could be due to nitrate.

And state inspection of agricultural discharge into groundwater sources that can cause nitrate is lagging. Many of the agricultural discharge permittees are located in rural areas of the state, and dairies alone are allowed to produce over 4 million gallons of discharge.

Roosevelt County has the highest amount of active agricultural permits in the state. Its most recent maximum nitrate levels were recorded at 3.37 parts per million, according to the county’s 2021 Water Quality Report.

Monsoon season is also ongoing in New Mexico, where rains can increase runoff that leads to excess contamination. This can be difficult to measure, Stoiber said.

Elevated nitrate levels can occur in New Mexico’s more urban areas, too. The five most populated cities and their maximum nitrate levels are shown below with data from the cities’ most recent Consumer Quality Reports.

Santa Fe’s levels have increased over the past couple of years and are especially high in relation to other cities. The city’s 2021 Water Quality Report attributes increased levels like this to rainfall and agricultural activity.

Lack of info on private wells

Over 170,000 New Mexicans depend on private wells for drinking water, according to the N.M. Environment Department. It’s up to those private owners, not the city or state, to test their water quality.

But because of the lack of testing requirements and the expensive nature of testing, most people don’t test their own wells regularly, Stoiber said, which has led to a lack of data about contaminants in private wells.

“There's not a lot of requirements for testing, and so most people don't do it,” Stoiber said. “It's expensive, and you assume that your water is probably pretty good.”

If private systems do have contaminants, treating it can get costly. Filtering out nitrate contaminants requires complex technology, Stoiber said, and specific systems are needed to do reverse osmosis or ion exchange.

New Mexico hosts water fairs throughout the year where owners of private wells can get their water tested for nitrate and other chemicals for free. Upcoming events can be found on the New Mexico Environment Department calendar. If treatment is needed, it’s up to the owner to pay for it.

“Private wells — you won't know what's in your well unless you test it,” Stoiber said.