Studies Strongly Link Exposure to Arsenic
In Utero and in Childhood to Stillbirth and Adult Disease

Arsenic is known to be a potent carcinogen when ingested over a long time, as it is by millions worldwide who rely on drinking water sources contaminated by the metal. New findings from Berkeley Epidemiology Professor Allan Smith’s Arsenic Health Effects Research Group implicate arsenic ingestion in more than just cancer. Smith said the results of two recently published studies on childhood and in utero exposure provide some of the first and strongest human evidence that exposure to a toxic substance in the earliest stages of life can have severe health consequences that manifest in adulthood. He also cautioned that arsenic exposure is still a problem in the United States.

Chile: Lung Cancer and Bronchiectasis
In a study of a unique population in the northern Chilean cities of Antofagasta and Mejillones, Dr. Smith’s team and Chilean colleagues have demonstrated that adults who were exposed to arsenic-contaminated water in utero or as children face a twelve- to 46-fold increased risk of death from lung disease.

The arid towns began drawing arsenic-laden drinking water from Andean rivers in 1958. Their exposure was reduced abruptly in 1971, when an arsenic removal plant was installed. Because exposure was so widespread and occurred at such high levels for a well-defined time period, the cities provide an ideal setting for studying long-term effects.

City residents who were children or born during that time were exposed to average arsenic levels of 860 μg/liter. (The current U.S. drinking water standard for arsenic is 10 μg/liter.) The groups’ death rates from lung cancer and bronchiectasis (a lung disease characterized by damage to the bronchi) were compared with death rates for these diseases in the Chilean population at large.

The researchers found that the lung cancer death rate of residents born between 1951 and 1958, when arsenic levels were relatively low, but were later highly exposed as young children, was seven times greater than the rate in the rest of Chile. A similar increase in lung cancer death rates was found for residents born between 1958 and 1971 who were exposed to high levels both in utero and as children.

Differences in bronchiectasis death rates were more profound. The death rate among the group exposed only as children was twelve times greater than in the rest of Chile. For the group exposed in utero, the rate of death due to bronchiectasis was an astoundingly 46 times greater.

These increases in mortality in young adults from early life exposure to arsenic in water are higher than those found worldwide for any other type of exposure.

India: Reproductive Health Effects
In West Bengal, site of the team’s reproductive health effects study with Indian collaborators, led by Research Epidemiologist Ondine von Ehrenstein, the team has shown that women drinking arsenic-contaminated water during pregnancy face a six- to thirteen fold increase in risk of stillbirth. Along with Bangladesh, West Bengal is home to the world’s largest population of people exposed to arsenic through drinking water.

From 2001 to 2003, the researchers interviewed 202 married women in the region to obtain information on past pregnancies and water sources used. They also measured arsenic levels in more than 400 wells used by the women, making it the first study of its kind.

The study region is rural, remote, and undeveloped, which has made studying the local population challenging. The women interviewed had little health documentation, and many did not know their exact date of birth.

The researchers found that women who drank water containing 200 μg/liter or more of arsenic had a six-fold increase in risk of stillbirth. Among women with arsenic-related skin lesions, the risk of stillbirth was increased thirteen-fold.

USA: Exposures from Private Wells
Meanwhile, back in the United States Craig Steinmaus, associate director of the research group, has provided more evidence that arsenic in water is not just a problem of foreign countries. While evaluating two new arsenic field test kits capable of detecting arsenic in concentrations down to nearly 10 μg/liter, he and Stanford student Christine George, who did the field work on a study in Nevada, encountered more than 30 wells with arsenic concentrations above 100 μg/liter, and many of these were over 500 μg/liter. The test kits were remarkably good at detecting low concentrations, but finding domestic wells with such high concentrations is disturbing. Smith said, “It’s easy to ignore arsenic in water, even in the U.S., because it is colorless, odorless, and tasteless.”

Von Ehrenstein summed up the implications of their findings. “Our studies show that effective measures are needed, especially to prevent exposure among women of childbearing age,” she said. “We can’t wait until women are already pregnant—at that point, it’s too late.”