"It's not that the situation is worsening," says Leon Moore, director of the environmental health division of Washtenaw County's public health department. "It's that we're doing more testing. We thought it was isolated to the northwest corner of the county ten years ago, and now we're finding arsenic in isolated pockets throughout the county."
The idea of arsenic poisoning is understandably terrifying. "Elevated levels of arsenic can cause bladder, lung, skin, and prostate cancer," says Dondzila. "There are also neurological effects," adds Moore, "for example, numbness in hands and other extremities as well as the face." And let's not forget increased risk of stroke.
As evidence of arsenic's dangers mounted, in 2001 the US Environmental Protection Agency announced that it was cutting the amount allowed in public water supplies from fifty to ten parts per billion. Soon after, Washtenaw County lowered the amount permitted in private wells to match the federal standard. Moore explains the thinking behind the change: "People over 50 ppb will have a problem," he says, "but at 10 ppb, you'd have to drink two liters a day for seventy years for it to have an effect."
What's a poison doing in well water in the first place? "Arsenic is a natural contaminant found in bedrock," explains Moore. "We have a lot of iron in Washtenaw County, and arsenic is attracted to iron. We've also found that we've seen higher levels of arsenic in homes that have been vacant for a while."