Even though it is still considered safe to consume, the drinking water at Mount Rushmore National Memorial violates a federal standard that was changed in 2006.

The water has tested for a slightly higher arsenic content than permitted by the Environmental Protection Agency, which considerably lowered the allowable level for the element.

Mount Rushmore superintendent Gerard Baker said he is concerned about resolving the issue but believes the water poses little danger.

"I know people that have been working here for over 30 years that have never been sick," Baker said. "As far as I'm concerned, it is not an immediate health risk.

Arsenic levels in Mount Rushmore's drinking water are currently at 14 parts per billion. That number was quite a bit below the old Environmental Protection Agency standard, which stipulated arsenic levels be less than 50 parts per billion.

However, when the agency changed that number to 10 parts per billion in 2006, the memorial was no longer in compliance.

Since then, Mount Rushmore officials have submitted quarterly water samples and have been posting warnings at the mountain, according to Mark Mayer, administrator for the state's Department of Environment and Natural Resources drinking water program.

"Once they knew they were going to be officially over the new standard, they started working with their park service engineering staff to look at alternatives to get in compliance," he said.

Mayer said the drinking water at the memorial doesn't pose an immediate danger. He said consuming water with higher-than-recommended arsenic levels can slightly increase the risk for various types of cancer, but only over long periods of time.

"It's not considered what we call an acute risk," he said.

Extensive studies caused the EPA to change the arsenic guidelines, according to Mayer. He deferred comments on the reason for the change to the EPA, which didn't immediately return a phone call from the Journal Friday.

Plans to drill another well at the mountain are currently under way, according to Duane Bubac, chief of cultural resources and facilities.

Drilling could start as soon as this month, Bubac said. Water quality consultants in Fort Collins, Colo., recently came to the memorial to help officials determine the best place to draw more water, he said.

If testing shows the water in the new location is usable, the location will be used for a new well. The water from the new well will be combined with the water being used right now, Bubac said.

Mount Rushmore will also look at a drinking-water filtration system, said Bubac.

Arsenic, a semimetal element, is odorless and tasteless, according to the state's DENR Web site. It can enter drinking water supplies from natural deposits in the earth or from agricultural and industrial practices.

According to DENR, arsenic has been linked to cancer of the bladder, lungs, skin, kidney, liver, nasal passage and prostate.

Mayer said the presence of arsenic just depends on geology. Some areas have more of the element than others, he said.

Two other locations in the Black Hills tested slightly above the recommended arsenic levels under the new rules, according to Mayer.

Wilhelm Court, a mobile home park outside of Hot Springs, tested two parts over the recommended levels at 12 parts per billion, Mayer said.

Doris Wilhelm, who owns the park with her husband, James, said the two are looking at connecting to a rural water source. She said she does not want to drill another well, because of the cost and because she has no guarantee the EPA won't change its standards again.

Shirttail Gulch, a housing development just outside of Deadwood, tested at 18 billion parts per billion, according to Mayer. The developers are looking at different options, including water treatment and connecting to Deadwood's water system.

Shirttail Gulch representatives didn't immediately return a phone call from the Journal on Friday.

Contact Ryan Woodard at 394-8412 or ryan.woodard@rapidcityjournal.com