Private wells, which are not subject to mandatory arsenic tests, provide approximately 40 percent of the New Hampshire water supply, according to Stanton. Although Dartmouth's water is supplied by a public source and has low contamination levels, the rest of the Upper Valley is serviced by private wells at the 40 percent rate.
Very few private wells are tested, and arsenic is difficult to discover otherwise, according to Stanton.
"Because arsenic is odorless, colorless and tasteless, you basically don't know if it's in your well or not," he said.
A New Hampshire state Senate bill that would have required testing in private wells failed in committee earlier this month, Rardin said, although researchers are attempting to revive regulatory efforts at the state level.
"[We're doing] whatever we can do to help provide information to make good decisions in terms of protecting public health," she said.
Through the Program, researchers have collaborated for several years with various government and environmental agencies, including the Environmental Protection Agency and the U.S. Geological Survey, with a goal of combining research and education, according to Rardin.
"That's what's unique about it it's a combination," she said. "We are trying to find ways to get that research into the hands of the people that can make use of it."
The screening of "In Small Doses" was attended by roughly 40 viewers, according to Stanton.
The group plans to judge the success of the movie and determine whether films are a useful medium to communicate their findings, Rardin said.
"Clearly this movie has shown us that this is a potentially good way to go, especially in making a shorter movie that can be shown on YouTube and on our web site," she said.
Arsenic levels in U.S. public water supplies are limited to a maximum of 10 parts per billion by the EPA, Stanton said, although researchers are still determining whether or not such a standard is low enough.
"Even at 10 parts per billion, arsenic does have effects on cellular function and on the ability of the immune response to fight off disease, for example," he said.
The regulation was set at 50 ppb until 2001, when the EPA lowered the threshold based on evidence that such high levels had negative effects on public health, Stanton said.
"You certainly don't want to be above 10 [ppb]," he said.
At sustained high levels, the toxin can cause or contribute to diseases ranging from cancer to heart disease, while also causing developmental defects in children and reproductive difficulties for women, Stanton said.
New Hampshire is at a particularly high risk from arsenic contamination because of the state's geology, according to Stanton.
"The bedrock in New Hampshire has high arsenic levels," he said, adding that the state used to be nicknamed "the arsenic state" because of the prevalence of arsenic due to mining in the region.
Once discovered, arsenic is relatively easy to remove from the water supply, Stanton said.
"[It costs] a couple hundred dollars to put something on the drinking tap where you take your drinking water and eliminate the arsenic," he said.
Test kits can be bought from the state for $10 to $15, Stanton said.
Arsenic contamination is an issue around the world. Other areas in New England, including Maine, also have high levels, Stanton said, and in some countries arsenic poses a health risk to as much as 50 percent of the population.
"[Arsenic is the] number-one toxic agent in the world," he said.
