Research involving hundreds of Maine children might represent a breakthrough about whether exposure to arsenic in drinking water — even at very low levels — could lead to reduced intelligence, scientists who conducted the study said Wednesday.

Scientists from Columbia University and the University of New Hampshire recently completed a five-year study of schoolchildren in Maine who had been exposed to arsenic in well water. The study showed that even at low levels, 5 or more parts per billion, arsenic consumed in drinking water could correlate to lower intelligence, as much as 5 to 6 points on IQ tests.

“Everyone was a little taken aback by that,” said Prof. Amy Schwartz of the University of New Hampshire, referring to the IQ results even at low levels of arsenic exposure. Schwartz coordinated the testing of Maine children. “This is a great piece of public health research. People shouldn’t panic, but be informed.”

A Maine health official said it’s estimated that nearly 20 percent of private wells in Maine would test at 5 or more parts per billion of arsenic.

Prof. Gail Wasserman, of Columbia University and one of the study’s lead researchers, said that the study is the first of its kind in the United States and more research needs to be done to see if the results can be replicated. The results were published in the April 1 edition of Environmental Health research journal.

“It is the first study to actually show a difference in IQ points in the U.S. based on water arsenic levels,” Wasserman said. “It is statistically significant.”

The study controlled for other factors that could affect intelligence, such as parenting skills, education levels of the mother and number of children in the home.

Arsenic has been previously linked to cancer. School districts in the Augusta area and York County participated in the study, with 272 elementary school students participating.

Wasserman said Columbia University studies in Bangladesh about 10 years ago also showed a correlation between arsenic and lower IQ, although the exposures to arsenic in Bangladesh were at much higher levels.

“We found associations (in Bangladesh) and we found tham repeatedly,” Wasserman said. “We really wanted to take this work back home.”

Wendy Brennan’s daughter Carrington, 14, was one of the children tested. She said it’s disturbing to think that the water supply she once assumed was safe may be harmful to her daughters or the two grandchildren, ages 2 and 1, who live with her at her home on Wings Mills Road in Belgrade.

Brennan said Carrington has been drinking the water her whole life and struggles in math, but she doesn’t know if those things are related.

The filtration system that the family installed cost $800 up front, and replacing the filter costs at least $100 every six months, or sooner if they drink more water.

“I worry when we can’t replace the filter as quickly as we should,” she said.

Michelle Keating, a member of the Fayette School Committee, called the results “scary,” though the well water at her Main Street home has tested within normal ranges for arsenic. Five or six IQ points seems significant, she said, especially if a child’s IQ is already below average.

“You’re looking at a variable that we can’t really control, and it’s really going to impact how we have to look at educating the children,” she said.

Schwartz said for U.S. residents the fixes are relatively easy for those with even small amounts of arsenic in their well water. People can buy filtration systems or simply avoid tap water by drinking bottled water.

The challenge is getting the word out to those who obtain their drinking water from wells to have their water tested, Schwartz said. More than half of Mainers drink from private wells.

The federal U.S. Environmental Protection Agency standard for arsenic in drinking water is no more than 10 parts per billion, but it’s far too early to tell whether the Maine study would lead to a further tightening of the standard.

Wasserman, however, noted that even small correlations found with lower IQ and lead paint paved the way for the lead paint ban in the 1970s.

“It proved worrisome enough to justify action and changing standards,” Wasserman said.

Any changes in EPA standards would likely take years, said Andy Smith, Maine Centers for Disease Control toxicologist, although the federal government is currently in the early stages of examining arsenic in drinking water.

While the U.S. EPA standard applies to public drinking water supplies, there is no federal mandate for levels in private wells or that those who own private wells have them tested. Smith said some wells in Maine have tested at much higher levels of arsenic.

But Schwartz said people can still do their own tests and make their own decisions.

“As a consumer, I know I wouldn’t wait around for a new standard,” Schwartz said.

Smith said the good news is that awareness seems to be increasing, as a survey showed the percentage of people who said they had their wells tested for arsenic increased from 27 percent in 2003 to 42 percent in 2009.

Most real estate transactions involving private wells in Maine require arsenic testing, although it’s not a state law to do so, Smith said. A new $51,000 federal grant will lead to more public education and outreach efforts around the state, Smith said.

“This study should be yet another reminder that if you haven’t had your well tested yet, to have your well tested,” Smith said.

Rich Abramson, former superintendent of RSU 38 (Manchester, Mount Vernon, Readfield and Wayne), helped recruit participants in his former school district and the others. He said it was beneficial for the RSU 38 communities because participants received free water testing, and it raised awareness about arsenic in well water.

Abramson said he hopes publication of the results — and a press conference that will take place in Augusta in late April or early May — will persuade more people to test their water and seek out resources to mitigate any problems they might find.

“It really should open up the conversation between people who are on dug wells and DHHS,” he said.

Joe Lawlor — 791-6376 [email protected] Twitter: @joelawlorph

Susan McMillan — 621-5645 [email protected] Twitter: @s_e_mcmillan