In high levels, this chemical could cause cancer. Is it in your well water?

A graphic showing county estimates for what is considered to be high levels of arsenic.
A graphic showing county estimates for what is considered to be high levels of arsenic. USGS

More than 2 million people nationwide may be drinking water from private wells that contain what are considered to be high levels of arsenic, according to a new study published Wednesday.

North Carolina is one of five states estimated to have the most people using wells that likely have high levels of arsenic, including: Michigan, Ohio, Indiana and California.

The U.S. Geological Survey and Centers for Disease Control and Prevention teamed on the study. A main finding is that out of roughly 44 million people in the lower 48 states who use private domestic wells, an estimated 2.1 million of them may be drawing drinking water that is potentially harmful.

Long-term exposure to inorganic compounds of the naturally-occurring element, as found in drinking water, is associated with increased risk of diabetes, high blood pressure and several types of cancer, according to the CDC.

Locations estimated to be of greatest concern include much of the West, areas in the Northeast and Midwest and portions of the southeastern Atlantic states.

At the county level, the study indicated “that 6 of the 10 counties with the largest number of people with high-arsenic wells are in New England; other top-10 counties are in Ohio, North Carolina, California, and Idaho.”

The USGS noted the study will help give homeowners an idea if they live in a high-risk area for arsenic – but that people need to have their water tested to be certain of arsenic levels at any given location.

Heating, boiling and bleaching water will not remove arsenic, according to the CDC, which recommends several water treatment options, including reverse osmosis and distillation.