Exposure to even low levels of arsenic in drinking water and food may increase the risk of developing, and dying from, heart disease, a new study suggests.
In the study, researchers analyzed urine samples from 3,575 American Indians in Arizona, Oklahoma and North and South Dakota, living in regions where arsenic levels in drinking water were “low to moderate,” meaning they were above the limit set by the U.S. Environmental Protection Agency, which is 10 micrograms per liter, but below 100 micrograms per liter.
Urine samples were collected between 1989 and 1991, and the participants were divided into four groups based on the concentration of inorganic arsenic in their urine. (There are two types of arsenic, organic and inorganic, inorganic arsenic is thought to be more toxic)
Source: http://www.livescience.com/39886-arsenic-heart-disease.html