Maine's largest public drinking water supplies are contaminated with hexavalent chromium, arsenic or nitrate, or all three chemicals combined.
That's according to a new national report and interactive map published by the Environmental Working Group.
"This is something that is common across the United States, including in Maine, where you get these mixtures of contaminants occurring together," said Sydney Evans, a senior science analyst with the nonprofit and a co-author of the peer-reviewed study.
Data displayed in the map reveal that more than 400,000 Mainers are drinking public tap water contaminated with one, two or all three of these chemicals. The data used are from public utilities; private wells are not included.
"Hexavalent chromium nationally has no standard, even though we know it is toxic at pretty low levels and it's kind of hard to treat for," Evans said. "It requires one of these advanced treatment methods to get rid of it."
And Evans said those same advanced technologies also filter out arsenic and nitrate.
The EPA typically evaluates the cost-benefit of treating each drinking water contaminant on its own, an approach the Environmental Working Group argues is costly, inefficient and moves too slowly to protect public health.
But their report concludes that if all three chemicals were screened and treated together, an estimated 50,000 cancer cases could be prevented nationwide.
