Long-term exposure to inorganic arsenic, a human poison that forms naturally in the Earth's crust, damages hearts of young adults, said a study published in Circulation: Cardiovascular Imaging, an American Heart Association journal.
The substance, which is found in groundwater, has been linked to various cancers, kidney damage, hypertension, cardiovascular disease and diabetes.
The study showed that the absorption of low-to-moderate levels of arsenic during a period of only five years was enough to cause a cardiovascular probem.
"Low-level arsenic exposure is associated with a disproportionate growth of the heart independent of hypertension and other traditional risk factors," the study's lead author, Dr. Gernot Pichler, said.
"The higher the arsenic content in drinking water, the greater the damage to the heart," said Pichler, who is a medical specialist at Hospital Hietzing/Heart Center Clinic Floridsdorf in Vienna, Austria.
"It is important for the general public to be aware that arsenic can be a risk factor for cardiovascular disease," Pichler said.
"Private wells are currently not regulated and people using private wells, including children and young adults, are not protected,” he added.
Being one of the "most abundant environmental metals worldwide," arsenic has an effect on "more than 200 million people" in more than 70 countries via drinking water alone, the University of Cambridge's Rajiv Chowdhury and Kim Daalen wrote in an editorial accompanying the study.
"The water from public suppliers must meet Environmental Protection Agency standards of less than 10 micrograms of arsenic per liter or 10 parts per billion," said hydrologist Joseph Ayotte of the US Geological Survey's New England Water Science Center.
"It's a really small amount, but there are evidence concentrations much lower than that can cause human health issues," Ayotte said.