A five-town school district based in Hallowell has signed on as the third local school system to participate in a study aimed at linking the presence of arsenic in well water to children’s intelligence.

Regional School Unit 2 will allow its students at Hall-Dale Elementary School in Hallowell and Henry L. Cottrell School in Monmouth to participate in the study, which is conducted by researchers affiliated with Columbia University and the University of New Hampshire, the universities said Tuesday.

RSU 2 joins Fayette and the Readfield-based Maranacook school district as participants in the Strategic Plan for Arsenic Research in Kids, or SPARK.

The district’s participation means researchers will seek as study subjects RSU 2 students from Farmingdale, Hallowell and Monmouth whose families use private well-water supplies. Researchers are seeking students in third, fourth and fifth grades.

A student’s participation will involve a home visit from a researcher, who will interview a parent and take home water samples. The researcher will also collect toenail samples from the participating students and have them take intelligence tests.

Families will receive information on participating in the study through notices sent home from school.

Those who participate, according to the news release, receive a free well water test for 22 contaminants and guidance on treating well-water supplies.

The researchers are seeking about 500 study subjects in the Augusta area since the U.S. Geological Survey has identified the area as one that has naturally occurring bedrock that contains high arsenic levels.

In the research the universities have done so far, 44 percent of the more than 170 Augusta-area wells tested have shown elevated arsenic levels, according to the news release.

Carol Ladd, of Wayne, is conducting the Augusta-area research. Contact her carolyn.ladd [at] unh.edu.