Researchers are finding a link between Rio Grande Valley groundwater and kidney cancer.

There's new information about the impact of contaminants in the soil and residents health. It's an issue in rural places across the state, where people are more likely to get water from a well.

"The water here isn't drinkable," Starr County resident Pedro Martinez said.

Residents at the community center in San Isidro say they have a well, but don't drink the water.

"Almost everyone buys water at the store," Martinez said.

Many residents say they've heard about an issue with arsenic. Arsenic is naturally occurring in the soil, and more concentrated in certain regions.

"We linked this to cancer data from the National Cancer Registry," Texas A&M School of Public Health professor Dr. Taehyun Roh said.

Roh is part of a team that compared arsenic concentrations in wells to the rates of kidney cancer across the state.

The research drew on more than 3,000 private well readings across the state, including the Valley. The work was done by the state and found a relationship between arsenic and kidney cancer.

"Our study suggests that even low level arsenic exposure below the EPA guidance level of 10 parts per billion in drinking water may be associated with an increased risk of kidney cancer," Roh said.

He says previous studies have linked arsenic to cancers of the bladder, lungs and skin.

Well contaminants have drawn the attention of state employees. In May, they visited San Isidro and other communities to offer well testing services.

In Valley counties, their data shows arsenic is showing up at 1 to 5 parts to a billion. Roh says 1 to 5 ppb increases the risk of kidney cancer by 6 percent. Rates of more than 5 PPB raise the risk by 22 percent.

Roh says the Valley is supplied by the Gulf coast aquifer, which tends to have higher rates of arsenic. The research on this issue at A&M continues.