Arsenic levels in some private wells exceeded the federal safety standard for public drinking water by 10 to100 times or more, even in areas where elevated arsenic risks were previously suspected, findings released Wednesday by the USGS said.
"We found large differences in concentrations from well to well, even at the town level, so residents need to test their wells to know their arsenic level," USGS scientist Martha Nielsen, who led the study in cooperation with the Maine Center for Disease Control and Prevention, said.
"The USGS has been working nationwide for many years to test groundwater for arsenic," Robert M. Lent, director of the USGS Maine Water Science Center in Augusta, Ga., said.
"Arsenic levels in this study are some of the highest we have seen in private wells," he said. "Nearly half of Maine's population use private wells for drinking water, so this issue quite literally hits home for many people."
The Maine CDC is distributing posters and brochures to selected town offices based on the proportion of residents on private wells and information about the presence of wells with arsenic.
"Statewide only about 40 percent of private water well owners have tested for arsenic, so it is crucial that we target our resources to the highest risk areas and nearby areas where we lack data," State Toxicologist Andrew Smith said.
High levels of arsenic have been linked to an increased risk for skin, bladder, and lung cancer, to reproductive and developmental problems, diabetes and to effects on the immune system, the USGS said.