Although health authorities have classified arsenic as a human carcinogen, emerging data suggest that long-term exposure to this naturally occurring element can also increase one’s risk for dying of heart disease. New findings reported today in the BMJ by researchers from the United States and Bangladesh provide more support for such a link with a study that found that persons exposed to unsafe levels of arsenic in well water are more likely to die of heart disease, a risk that was greater in those drinking from wells with higher levels of this toxin.
The researchers followed up 11 746 men and women in Araihazar, Bangladesh, whose source of drinking water was 1 of the 5966 wells in the study area. The rate of death from cardiovascular disease was 214.3 deaths per 100 000 person-years in residents who drank water with comparatively low levels of arsenic (less than 12 ppb of arsenic) compared with 271.1 deaths per 100 000 person-years in residents who drank water with arsenic levels at 12 ppb or greater.
The findings have worldwide implications because arsenic occurs naturally in groundwater, usually from contact with arsenic-rich rocks. Not all wells used for drinking water are affected, but those containing unsafe levels of arsenic can pose a public health threat for those who use them. In the United States, drinking water for approximately 15 million households, or more than 42 million people, is drawn from private wells, which are not covered by federal regulations that require ensuring the safety of public drinking water systems.
An accompanying editorial in the BMJ notes that arsenic is tasteless and cannot be seen in water. The editorialists recommend that in all places in the world where people get their drinking water from wells, clinicians should ask their patients if the water has been tested for arsenic. In the United States, the federal Environmental Protection Agency (EPA) has set an acceptable level of arsenic at no more than 10 ppb.
But the EPA’s regulations do not apply to owners of privately owned wells, who are responsible for ensuring that their water is safe and has acceptable minimum levels of arsenic and other contaminants.
For more information:
The Centers for Disease Control and Prevention offers information and links to help private well owners ensure their water sources are safe.
Maps from the US Geological Survey provide a national snapshot of arsenic concentrations in US groundwater.