Dartmouth Research Informs N.H. Action on Arsenic in Drinking Water

Granite State lawmakers voted to reduce the level allowed in public water.

Research from Dartmouth’s Toxic Metals Superfund Research Program formed the backbone of technical information used by the state of New Hampshire in its recent decision to reduce arsenic levels in public drinking water in the state.

For over 20 years, Dartmouth has been studying the health effects of arsenic, a naturally occurring but toxic chemical that seeps into the water supply from granite bedrock.

“Arsenic poses a significant health risk to many citizens of New Hampshire,” says Celia Chen, director of the Dartmouth Toxic Metal Superfund Research Program. “This is definitely a welcome regulatory change that will help people across the state.”

In 1995, Dartmouth’s Toxic Metals Superfund Research Program began studying the effects of arsenic on human health. The Children’s Environmental Health and Disease Prevention Research Center at Dartmouth joined the effort in 2010, specializing in arsenic’s impact on children’s health.

Dartmouth’s studies have found that long-term exposure to low levels of the pollutant increases the risk of certain cancers and may also be linked to heart disease and diabetes.

The new state regulation, signed into law on July 12, reduces allowable levels of arsenic in public drinking water to 5 parts per billion (ppb). New Hampshire’s action makes the state the first in New England and the second in the country, after New Jersey, to halve arsenic levels from the 10 ppb federal limit.

“Reducing maximum arsenic levels in public drinking water is consistent with the decades of research from Dartmouth and others linking the contaminant to negative health effects,” says Chen.

Studying arsenic at Dartmouth is an interdisciplinary effort that includes several research labs across the campus as well as partnerships with state and federal agencies.

Through the New Hampshire Birth Cohort Study, Margaret Karagas, the James W. Squires Professor of Epidemiology, and researchers from the Superfund program and Children’s Research Center work with populations that are the most vulnerable to arsenic contamination—pregnant mothers and young children who drink private well water. The research group follows mothers and babies from birth through middle childhood and beyond. Hair, nails, urine and other biomarkers are collected from study participants for evaluation.

Samples from Karagas’ lab are sent to the Dartmouth Trace Elements Analysis Core lab, where Research Professor Brian Jackson and his colleagues analyze them for arsenic levels. The results give researchers a more complete understanding of the connection between low-level arsenic exposure and human health.

“Our findings to date suggest that the effects of arsenic may occur at lower levels of exposure than previously thought,” says Karagas, the director of the Children’s Environmental Health Center, which is one of the only groups in the country conducting epidemiologic investigations of this type.

Other Superfund research at Dartmouth looks at the dangers of arsenic on the immune system in the lungs and how arsenic enters the food supply.

Although the new state regulation targets arsenic only in public water systems, Dartmouth’s research extends to arsenic that comes from both public water and private wells. About one-third of the public water systems in the state have a detectable amount of arsenic in their water. Approximately the same fraction of private wells has arsenic levels above the state’s new public water limit.

“Arsenic is naturally present in the Earth’s crust, and also may arise from human sources. The new legislation will reduce arsenic in public water, but it is important for private well users to test their water,” says Karagas.  

Dartmouth’s teams partner with the New Hampshire Department of Environmental Services (DES) and other state and federal agencies.

“State residents have benefited from the years of dedicated work by DES, the N.H. Department of Health and Human Services, the U.S. Geological Survey and the U.S. Environmental Protection Agency to ensure that citizens have access to the safest possible drinking water,” says Chen.

Now that the new regulations have become law, the Dartmouth team will continue to conduct research and outreach activities related to arsenic. Dartmouth’s Toxic Metals Superfund Research Program will also continue to lead the work of the N.H. Arsenic Consortium.

“New Hampshire policymakers have made a change that will make a big difference for public health. Hopefully this will encourage other states to examine this issue and also encourage private well owners in our state to have their water tested,” says Chen.

Arsenic is tasteless, odorless, and colorless. In addition to lurking in drinking water, the chemical is found in rice, rice products, and other foods. Additional information about arsenic may be found on the Dartmouth Toxic Metals Superfund Research Program website “Arsenic and You.”

David Hirsch can be reached at [email protected].