Arsenic levels in an estimated 20 percent of Maine's public water supplies are higher than those now considered safe for human consumption, according to state officials.
Those that draw their water from private sources, the percentage could be higher. Half of all drinking water in Maine comes from private wells, but the state has no formal program to deal with water quality issues and questions, said state toxicologist Dr. Andrew Smith
Tests performed by the state reveal various results from some data showing as much as 10 to 15 percent of all groundwater supplies in Maine have elevated arsenic levels while other data shows 2 to 5 percent.
The current MCL of 50 ppb has been in discussion during recent months since the proposed 10 ppb was delayed by the Bush Administration pending further study.
Arsenic, a common element in the earth's crust, has been linked to bladder and lung cancer and other illnesses.
Surface water is relatively free of arsenic, which collects in rocks and seeps into underground water sources, according to state geologist Robert Marvinney. Arsenic has never been a problem in places like Lewiston-Auburn, Greater Portland and other large water systems that draw from lakes and ponds.