When Lily Benedetto brought home a note from Marshwood Great Works School in South Berwick last spring asking if she could be part of an arsenic groundwater study, her parents gave her the go-ahead.

All she had to do was surrender some toenail clippings and take an IQ test. The well water at her home in Eliot was tested for free for 22 possible contaminants. Lily received a $25 gift certificate for her efforts.

But for her parents, Bob and Pamela Benedetto, the study was a mixed blessing. They discovered after nine years in their home that their family had been drinking water with levels of arsenic above federal safety levels. They, and their dog, have been drinking only bottled water ever since.

“I am really glad we know,” said Pamela Benedetto.

The Benedettos are among hundreds of families who have taken part in a Columbia University and University of New Hampshire study of the potential link between arsenic exposure in children and the development of cognitive skills.

Arsenic has been shown to cause health problems, including many bladder, lung and other types of cancer, cardiovascular disease, circulatory problems and developmental problems in children.

Maine and parts of southern New Hampshire have become the focus of several studies looking at how arsenic may impact health.

The region has high levels of arsenic that occurs naturally in bedrock. While there are similar arsenic hot spots in other parts of the country, those regions are served by municipal water systems which under federal law must remove the arsenic.

In Maine, 56 percent of residents live in homes with private wells, which are exempt from regulation, according to a state survey last year by the Maine Center for Disease Control and Prevention, the U.S. Geological Survey and the U.S. Centers for Disease Control and Prevention. About 10 percent of those wells have arsenic levels above 10 micrograms per billion, the federal Environmental Protection Agency’s minimum safety standard, according to the U.S. Geological Survey.

Since that information was uncovered, about 61 percent of the private wells in Maine have been tested for arsenic, said Andrew Smith, state toxicologist. No one knows how many private well owners have taken steps to stop the contamination.

That makes Mainers ideal candidates for epidemiological studies looking at arsenic.

At the University of Maine, biochemist Julie Gosse and a team of student researchers have been looking at whether there is a link between arsenic in drinking water and asthma. Maine, New Hampshire and Rhode Island have the highest asthma rates in the nation. While the researchers found no link to asthma, they did determine that arsenic in drinking water disrupts immune defense cell function. The research is continuing.

The Columbia and UNH study, called the Strategic Plan for Arsenic Research in Kids, involves third-, fourth- and fifth-graders in South Berwick, Eliot, Monmouth, Hallowell, Farmingdale, Fayette, Manchester, Mount Vernon, Readfield and Wayne, and three New Hampshire communities.

About 260 children have been tested so far with another 240 to go before the study is complete. So far the study has determined that 44 percent of the wells tested in Maine had elevated arsenic levels. But any conclusions about how the levels have affected the intelligence of children drinking the water are two years away, said Joseph Graziano of Columbia University, who is principal study investigator.

Graziano said the study is important because it will help researchers better understand what levels of arsenic are safe in well water, in Maine and other parts of the world where contamination is much worse, such as Bangladesh.

In Bangladesh, 77 million people — more than half the population — have been exposed to dangerous levels of arsenic in groundwater. A 10-year study published earlier this year of deaths among Bangladesh residents concluded 20 percent of those deaths were due to arsenic poisoning.

Studies in Bangladesh have also found arsenic exposure is associated with intelligence deficits in children.

“The purpose in Maine and New Hampshire is to see if we can replicate this and (we) hope we can’t,” Graziano said.

He said there are big differences between the rich diets of children in the United States and those in Bangladesh, where nutrition is poor.

“Nutrition matters a lot in regard to arsenic toxicity,” Graziano said.

Also, American diets include water from multiple sources, such as bottled water and soft drinks — not so in Bangladesh.

Some of those who have taken part in the study say it has opened their eyes to a problem they did not know existed.

“You think Maine, Poland Spring, I am living in Maine, I can trust the water. But my assumption that it is pure as the driven snow is just not the case,” said Bob Benedetto.

Lisa Dinsmore of Eliot said her son, Riley Dinsmore-Patch, 11, learned something new and felt good about contributing to a large body of research.

“Riley felt really comfortable,” Dinsmore said.

She encouraged other families to participate.

Now she her husband, Scott Patch, are wondering how to proceed after learning their water tested just below the safety level. While those in the study receive guidance about how to treat their water, abatement can be expensive. Dinsmore said one estimate they received was $1,200 for a filter system.

The study has been a learning experience for the Benedettos as well. They bought their house before safety levels for arsenic were lowered from 50 micrograms per liter in 2006, a fact of which they were unaware. Bob Benedetto said he was surprised to find that Maine has no laws that regulate the testing of well water.

“You would think the state could design legislation to protect the people,” he said.

Smith, the state toxicologist, said that while the Legislature has taken up the issue of private well testing in the past, it has met opposition from real estate associations and others.

The Maine Association of Realtors did develop a model purchase and sales agreement that lists arsenic as one of the possible contaminants for which well water should be tested.

Smith said a new survey is in the works to determine how many private well owners take steps to mitigate elevated arsenic levels and how well they maintain their treatment systems in the future.

Graziano said his study will also look back to see whether people took corrective measures and, if they didn’t because of financial reasons, to try to get them some help.

“We will try to work with local organizations and get some assistance,” he said.

Staff Writer Beth Quimby can be contacted at 791-6363 or at:

bquimby@pressherald.com