People in Bangladesh exposed to high levels of arsenic in drinking water were more likely to report shortness of breath in a new study than those who drank water with safer arsenic concentrations.

Though researchers didn’t try to diagnose the study subjects with any specific illnesses, they noted in the European Respiratory Journal that diseases of the heart and lungs are common reasons people have trouble breathing.

The study is the latest in a growing body of evidence suggesting that arsenic may not just be a carcinogen, but could potentially do other kinds of damage to organ systems.

The World Health Organization considers an arsenic level of less than 10 micrograms per liter to be acceptable for drinking water. In Bangladesh, where natural underground deposits of the metal make contamination levels notoriously high, the standard for safe drinking water is less than 50 micrograms of arsenic per liter.

“It’s really a universal problem, but Bangladesh has very high levels. People are exposed because most of them drink well water,” said Kristina Zierold, an epidemiologist who has studied arsenic at the University of Louisville in Kentucky but didn’t participate in the new report.

Researchers interviewed almost 12,000 adults in Bangladesh, asking whether they smoked and if they’d had trouble breathing at any time in the last six months.

Taking into account smoking, which is known to cause shortness of breath, Dr. Gene Pesola from Columbia University in New York and his colleagues linked the interview responses to levels of arsenic measured in local well water.

Among non-smokers, five percent of those who drank water with arsenic levels below 50 micrograms per liter reported recent shortness of breath, compared to eight percent with higher arsenic exposure.

And the more arsenic was in the water supply, the more participants reported trouble breathing. Non-smokers whose water had the most arsenic - over 90 micrograms per liter - were about twice as likely to have breathing problems as those who drank water with less than seven micrograms of arsenic per liter.

Although smokers had more breathing problems than non-smokers to begin with, arsenic exposure was also linked to a higher likelihood of having shortness of breath among people who smoked, which included the majority of men in the study.

The researchers explained that arsenic has been tied to inflammation and widening of the airways, which may lead to breathing problems.

While Bangladesh and some parts of India have the most severe drinking water contamination, researchers agreed that arsenic exposure is a concern in many parts of the world - especially because some studies have suggested that even levels at or below WHO standards can be harmful.

“The reality is, in the U.S. we have people who drink well water too in places where arsenic is in the bedrock,” Zierold told Reuters Health.

Exposure is also high in parts of Africa and Northern Mexico, said Dr. Ana Navas-Acien, who has reviewed the evidence on arsenic’s health implications at the Johns Hopkins Bloomberg School of Public Health in Baltimore.

She said that arsenic exposure can be mitigated by drilling new wells from aquifers that are arsenic-free, or adding filtering systems to water sources. But building and maintaining that infrastructure can be expensive, she acknowledged.

It’s clearly technically feasible, said Navas-Acien, who wasn’t involved in the new research. “It’s an issue for small, poor communities.”

But, she told Reuters Health, with current evidence that arsenic may be implicated in cancer, cardiovascular disease and breathing problems, intervention is essential.

“Right now with the information that we have it’s unacceptable that there are still many people around the world, including in the U.S., that are still drinking water with levels above the arsenic standard.”

SOURCE: European Respiratory Journal, online November 16, 2011.