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Arsenic Pollution On The Cheyenne River Reservation

A new study shows dangerous levels of arsenic contamination on parts of the Cheyenne River Reservation.  Arsenic is known to cause cancer, and the study points to a human health risk from the current concentrations found in some areas.

The study adds to the current body of research, showing that the pollution from historic mining in the northern Black Hills was carried down the Cheyenne River and deposited in areas where residents work and recreate.

Scientists the United States Geological Survey, the South Dakota School of Mines and Technology, the Cheyenne River Sioux Tribe, and the EPA have contributed to the research. SDPB's Charles Michael Ray has this story.

The study points to a handful of areas where soil samples show levels of arsenic that exceeded what the EPA considers safe.  Maria Squillace is a grad student at SDSM&T.  She presented her research at a conference in Rapid City.  Squillace says the areas where high arsenic levels were found include a popular place for picnicking and inside a horse coral at a private ranch. She says the EPA and the Tribe are working on much more extensive research to better categorize the health risk.

“It's good to know that somebody is in there looking at this right now.  But it is scary that some of these people have probably lived on that ranch their whole life and maybe they’re not totally aware of it,” says Squillace.

Maria Squillace an SDSM&T grad student at a soil sampling site near the Cheyenne River. Photo thanks to Dr. Jim Stone, SDSM&T.

Squillace says much more study is needed.  That's where EPA Toxicologist Dr. Deborah McKean comes in. Dr. McKean is heading the EPA effort to look at the contamination on the Cheyenne River.  EPA researchers are working closely with tribal officials.  McKean says it’s important to protect human health by studying areas where contaminants exist.  She says the EPA also examines any potential adverse health effects from exposure to pollution.
“And if that exposure is associated with some contaminate weather it’s in soil or in water, the EPA would pursue if something could be done to reduce that exposure,” says McKean.

But McKean adds that just finding levels of arsenic in the soil is only part of the study. The research also examines how often humans interact with contaminated areas.  McKean says officials hope to announce results by the end of the year.