Contaminants common in S.D. drinking water, but most within legal limits
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Contaminants common in S.D. drinking water, but most within legal limits

Northdale water towers

Among the roughly 650 water systems in South Dakota, smaller rural systems tend to face more challenges due to a lack of money and resources or the age of the system. The Northdale Sanitary District is a system that serves about 1,100 people along the border of Meade and Pennington counties. The system was cited by the state for not having a certified system operator in 2015 and for failing to monitor for arsenic in 2018.

State testing data shows several contaminants harmful to human health are commonly found in the drinking water in South Dakota.

In most cases, however, tap water generated by the state's 650 drinking-water systems fall well within guidelines set by the U.S. Environmental Protection Agency for safe consumption of lead, copper, nitrates, arsenic, radium, uranium, and a chlorine sanitation byproduct called trihalomethanes.

All of those chemicals -- most of which are known carcinogens -- are often found in much of the drinking water tested regularly by South Dakota water system operators and reported to the state and federal governments. Except in rare cases, such as when a system failure occurs or a contaminant builds up over time, the contaminant levels fall below legal guidelines set by the EPA.

But an environmental group is trying to change the definition of “safe” and strengthen federal and state guidelines for what is considered “healthful” when it comes to the presence of dangerous contaminants in drinking water. In its annual report on America’s drinking water supply, released Oct. 26, the nonprofit Environmental Working Group noted many federal water-quality standards have not been updated in 20 or even 50 years, and there are no legal limits for 160 contaminants that can make their way into the American drinking-water system.

“The disturbing truth shown by the data is that when most Americans drink a glass of tap water, they’re also getting a dose of industrial or agricultural contaminants linked to cancer, harm to the brain and nervous system, changes in the growth and development of the fetus, fertility problems and/or hormone disruption,” the EWG said in a news release.

The study’s two main goals, according to Alexis Temkin, a staff toxicologist at EWG, is to provide Americans with an easy way to find recent data on the quality of their drinking-water system and to highlight the need to be update and strengthen contamination standards.

“Primarily, what we know is that ‘legal’ doesn’t necessarily mean ‘safe,’” Temkin said. “The vast majority of the utilities across the country get a passing grade by the EPA even though contaminants are almost always present.”

The EWG water-quality study is examining test results from nearly 50,000 water systems across the U.S., including all of those in South Dakota that are regulated.

The EWG, however, creates its own set of safety guidelines based on the most stringent health guidelines and scientific data currently available; some are from the state of California, which is known for its aggressive approach to protecting drinking water, Temkin said.

Based on its own safety guidelines, the group found nearly all South Dakotans are consuming drinking water with contaminants at unhealthy levels.

The EWG study used a two-year average of data from 2015-17. It reported that 291 South Dakota utilities serving about 703,500 people had unhealthful levels of trihalomethanes, or THMs, the chlorine byproduct that can cause bladder and skin cancers and inhibit fetal growth. The study found that 234 systems serving 458,500 people had unhealthful levels of nitrate; 83 systems serving 421,250 people had unhealthful levels of chromium; 37 systems serving 201,000 people had unhealthful levels of arsenic; and 210 systems serving 220,000 people had unhealthful levels of radium or uranium.

Inspection data from the South Dakota Department of Environment and Natural Resources reveals that from 2012 through 2016, 712 water systems across South Dakota were cited 2,673 times for water-quality or system violations that potentially affected 334,300 people.

A spokesman for the DENR, which is responsible for water testing, system monitoring and enforcement of contaminant limits, said the EWG study represents an unfair “apples-to-oranges comparison” of water-quality standards.

“Historically, EWG has highlighted a state’s water quality first based on non-enforceable goals rather than enforceable maximum contaminant levels,” DENR spokesman Brian Walsh wrote to News Watch in response to written questions.

The highly strict contaminant standards used by EWG may create a misleading picture for the public that drinking water across the country and in South Dakota is unsafe, said Jeremiah Corbin, source-water protection specialist for the South Dakota Association of Rural Water Systems.

“I’m concerned that they may give people the misconception that their water is not safe when based on drinking-water standards it is safe,” Corbin said. “By cherry-picking what health levels they’re going to choose for safe water, it unfairly muddies the conversation.”

Corbin said maintaining high-quality drinking water is an ongoing challenge that is taken seriously and undertaken with great success by operators of the roughly 300 water systems that are members of the association.

“Our goal is to send out a product that a newborn child could drink and be healthy, and I think we’re doing that,” Corbin said. “I’m not saying there aren’t systems that aren’t perfect, but generally speaking I think the water systems and the state do a marvelous job of providing clean drinking water.”

The EWG report makes clear the differences between its health standards and the legal limits, and the gap is often very wide.

For example, the EWG health limit for TMHs is .15 parts per billion, compared with the legal level of 80 ppb. For nitrates, the EWG health limit is .14 ppb, compared with the long-held federal safety standard of 10 ppb; for arsenic, the EWG health limit is .004 ppb, compared with the federal standard of 10 ppb; and for radium, a common contaminant in South Dakota drinking water, the EWG limit is .05 pico curries per liter, compared with the federal limit of 5 piC/L.

Only five South Dakota systems were found to be in violation of EPA contaminant standards during the EWG study period:

  • Bonesteel (275 customers) was above the legal limit for nitrates.
  • Buffalo Gap (126 people) and the Cottonwood Grove Mobile Home Park (30 people) were above legal limits for uranium.
  • Cedar Gulch #2 (33 people) and the Shirt Tail Gulch Development (60 people) tested above legal limits for radium.

In 2016, the state recorded 365 total violations by 123 water systems that served about 72,000 people. That was down from a high of 705 violations by 143 systems affecting 82,500 people in 2014.

The DENR requires that system operators regularly take water samples for testing; the frequency is dictated by the contaminant sought and the size of the system. Testing for lead and copper is done only every three years, and some other contaminants are tested for annually. Meanwhile, the Sioux Falls system tests water three times daily for bacteria.

A spot-check of systems across the state reveals that many have been flagged for violations over the past five years.

The Hill City water system in Pennington County, serving 950 people, was cited for exceeding limits of arsenic in July and October 2018, according to state documents. The city of Springfield in Bon Homme County, which serves about 2,000 people, was cited for exceeding limits of THM on five occasions from 2015 to 2019.

The water system in Pierre sent an advisory to the roughly 14,000 people it serves in March 2019 after the EPA found high levels of manganese in the water supply.

The letter noted that although manganese is not a regulated substance within EPA monitoring programs, it can cause brain illnesses if ingested by infants. Long-term consumption of manganese by adults can cause nervous-system and brain illnesses.

The warning noted that Pierre is building a new water-treatment system that will use surface water from the Missouri River. The state has provided Pierre with a $36.9 million loan for construction of the water plant, said Walsh of the DENR.

According to the EWG report and to a News Watch review of state water-system inspections, higher and more frequent levels of contamination tend to occur in smaller, more rural water systems.

Corbin acknowledged that larger systems in Sioux Falls, Rapid City and Aberdeen have larger customer bases and more money to consistently improve operations and stay on top of new technology.

“Rural systems with small populations tend to have more challenges,” he said. “There’s so many variables in a small system; some rural systems have challenges just getting a certified operator in their community.”

One of the most problematic systems in South Dakota serves only about 35 people in the Cedar Gulch #2 subdivision just east of Rapid City. Between July 1, 2014, and July 1, 2019, water tests revealed 64 violations of state regulations, including 32 listed as “exceedance of allowable contaminant levels” for presence of radium and alpha emitters, both radioactive compounds that can cause cancer. Other violations were for failing to monitor for other harmful contaminants and for not having a certified system operator in 2015.

Contamination can occur due to a number of factors, including inefficient treatment systems; from leaching of contaminants from lead pipes and aging system components; from agricultural, industrial or septic-system runoff; or owing to infusion of materials within geologic formations surrounding a well.

Taking water from an unreliable source can also lead to problems.

That appears to be the case for the privately owned water system in Owanka, which serves about 23 residences and 52 people about 10 miles southwest of Wasta. Marvin Williams, president of the water board, said a few people have water filters on their taps due to consistently high levels of radium in the water but that most drink the water without worry.

Williams said the Owanka system uses the Inyan Kara Aquifer for its water, a highly saline source that mainly is used for watering livestock. The system has been cited by the state 14 times for having high levels of radium from 2016 to 2019. The system also showed a positive test for total coliform bacteria in 2018, state records show.

The state DENR has stepped in and last year provided a $50,000 grant to the Owanka system to fix the problem with radium contamination, likely through installation of treatment systems that will be installed on taps in the homes of system users, according to the DENR.

The origins of other problems are easier to pinpoint. For the adults and children living in about 95 homes near Ellsworth Air Force base in Box Elder, the unsafe levels of contaminants in their water is known to have come from the use of firefighting foam at the base that contained polyfluoroalkyl substances, or PFAS. The cancer-causing chemical has been found above EPA safe levels in 26 private wells, including a well that serves 200 residents of the Plainsview Mobile Manor community.

In response, the military has provided bottled water to residents until an alternative water source can be found.

Maintaining a safe supply of drinking water to communities across an entire state requires constant testing and monitoring and a steady pace of spending to keep systems operational.

This year, the Board of Water and Natural Resources within the DENR will spend $64.5 million to aid municipal and regional water systems, said Walsh, the DENR spokesman.

Walsh noted that South Dakota water systems have a great track record in meeting the EPA goal of having 95% of water users in the state meeting all health standards related to their water. He said the state has had 98% to 99% of systems meet that standard over the past five years.

In 2018, the state provided grants, loans and principal forgiveness to Rapid City to help the city fix wells and water-delivery systems for a neighborhood of 600 people living just outside city limits whose water supplies failed to meet EPA standards, Walsh said.

The city performed much of the infrastructure development and is now serving the population with city water, Walsh said of the $7.5 million project that improved water for residents of the Mesa View, Valley Heights, and Terra Cotta subdivisions and properties in the Longview Sanitary District.

“The ability to provide grant and principal forgiveness by the state is the primary reason the project was possible and affordable to the new users,” Walsh wrote.

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