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Dartmouth Researchers Hail N.H. Bill to Cut Arsenic Allowed in Water

Valley News Staff Writer
Published: 1/11/2019 12:04:04 AM
Modified: 1/11/2019 12:04:22 AM

Concord — A group of Dartmouth researchers studying the effects of toxic metals is applauding a plan to reduce the allowable threshold for arsenic levels in New Hampshire’s drinking water.

The state Department of Environmental Services last week proposed halving its arsenic limit to five parts per billion. In a recent report, officials said the reduction is aimed at protecting the health of Granite Staters.

Arsenic can increase the risk of bladder cancer and reduce the IQ of school age children, according to researchers.

The colorless, odorless and tasteless semi-metal also is known to negatively affect the health of pregnant women and their children, contributing to increased blood pressure, increased risk of gestational diabetes and upper respiratory tract infections in infants exposed to arsenic in the womb.

“Our research supports (the DES) recommendation to reduce the limit,” said Britton Goodale, a member of Dartmouth College’s Toxic Metals Superfund Research Program. “It would help protect the health of people drinking water in New Hampshire.”

Goodale said research also is showing that low levels of arsenic can affect the immune system, particularly hampering cells responding to infections in the lungs.

If the Legislature approves the move, New Hampshire would become the second state to lower its arsenic limit from the federal standard of 10 parts per billion. Vermont is at the 10 parts per billion level, while New Jersey made the move to the five parts per billion standard in 2006.

New Hampshire has the highest risk of bladder cancer cases in the country, and is 37 percent above the national average, according to the federal Centers for Disease Control and Prevention. And the state has attributed part of that to a high rate of exposure to arsenic through private well water.

While the new limit would apply only to public water systems, officials hope that private well users would follow suit and implement better filtering technology to keep up with safety standards.

The state’s proposed limit comes in response to a 2019 law that called on DES to study arsenic levels and recommend ways to improve water quality.

Then-state Rep. Mindi Messmer, D-Rye, initially introduced a bill to set New Hampshire’s arsenic limit at four parts per trillion, which would become the most stringent standard in the country. But the legislation was amended after state officials warned that current water testing and treatment technology couldn’t filter that low a level. Instead, lawmakers told DES to propose a new standard by Jan. 1.

In its study, the state looked into lowering the standard further but determined that it would be too costly for public water systems to filter out arsenic levels below five parts per billion, said Paul Susca, supervisor of the planning unit in the drinking water program at DES.

Research also was clear that the five parts per billion mark would have a measurable affect on people’s health, but the science hasn’t produced as clear determinations for levels below that, he added.

“As studies are done at lower levels, and also as technology improves to treat water, potentially in the future, we would revisit this,” said Goodale, who added that no amount of arsenic is known to be safe.

“Ideally, we’d love to just remove all contaminants from water,” but officials also have to take into account what’s feasible, she said.

Partnering with epidemiologists at Dartmouth, the DES found that the new limit could prevent several arsenic-related deaths and illnesses over the next 70 years.

Between three and eight cancer-related deaths can be avoided during that time period, according to the DES report. The proposal also could prevent six to 19 cases of bladder- and lung-related cancer cases over the same time period, as well as four cases of skin cancer.

The new rule also is likely to cost water treatment plants millions of dollars in both new equipment and maintenance costs to comply with, according to the state’s report. Sites that might impact local groundwater, such as landfills, also might need to spend on new technology.

Homeowners looking to reduce arsenic in their private wells to meet the new standard could expect to pay between $1,500 and $3,000, according to the DES study.

The rule requires legislative action before it can take effect, Susca said. And with bills already being filed to lower the arsenic level, such action is possible this year.

Tim Camerato can be reached at or 603-727-3223.

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