The Arsenic in Our Drinking Water

SEPTEMBER 20, 2013, 2:13 PM 
By DEBORAH BLUM

The baby with the runny nose, the infant with a stubborn cough — respiratory infections in small children are a familiar family travail. Now scientists suspect that these ailments — and many others far more severe — may be linked in part to a toxic element common in drinking water.

POISON PEN

Deborah Blum writes about chemicals and the environment.

The element is naturally occurring arsenic, which swirls in a dark, metalloid shimmer in soil and rock across much of the United States and in many other countries. It seeps into groundwater, but because the contamination tends to be minor in this country, for many years its presence was mostly noted and dismissed by public health researchers.

They’ve changed their minds. Long famed for its homicidal toxicity at high doses, a number of studies suggest that arsenic is an astonishingly versatile poison, able to do damage even at low doses. Chronic low-dose exposure has been implicated not only in respiratory problems in children and adults, but in cardiovascular disease, diabetes and cancers of the skin, bladder and lung.

Trace amounts in the body interfere with tumor-suppressing glucocorticoid hormones, studies show, which is one reason that arsenic exposure has been linked to a range of malignancies. Arsenic also interferes with the normal function of immune cells. It damages lung cells and causes inflammation of cells in the heart.

Researchers first became aware of these problems in so-called hot spot countries like Bangladesh, where arsenic levels in water can top 1 part per million. Decades ago, public health agencies there sought to replace microbe-contaminated surface water with well water. Only later did geological surveys reveal significant aquifer contamination from bedrock arsenic.

Scientists now report health risks at lower and lower levels of exposure in that country. In July, researchers at the University of Chicago found that residents of Bangladesh chronically exposed to arsenic at a mere 19 parts per billion showed signs of reduced lung function. At levels of 120 p.p.b. or higher, their ability to take in oxygen resembled that of long-term smokers.

More