The state Department of Natural Resources says it doesn't know why high levels of molybdenum have been found in many wells in southeastern Wisconsin.
The DNR completed an extensive study that yielded "inconclusive" results on the source of the molybdenum, Southeast Regional Director Eric Nitschke said. Questions on where the molybdenum is coming from were asked often during a public meeting Thursday night in Caledonia.
"We understand there are some folks that would rather those results be conclusive," Nitschke said in an interview. "We aren't able to give that."
Molybdenum is a naturally occurring element in the earth's crust and, in small amounts, is an essential part of people's diets.
However, it's also a byproduct of coal combustion and industrial waste. Drinking water with high levels of molybdenum carries risk, including digestive problems and gout, according to a DNR report.
The DNR recently tested for molybdenum in 153 private wells in Franklin, Muskego, Norway and Raymond and found high levels of the element in 44 of them.
Since then, the department has planned a series of open house-style meetings, the first of which was held Thursday at Trinity Lutheran Church, to educate the public and answer questions. The DNR also continues to collect data and work with other agencies, including the Department of Health Services and the Department of Safety and Professional Services.
More than 11,000 private wells fall within the area in which the DNR advises tests. The area includes the towns of Caledonia, Raymond and Norway in Racine County; Muskego in Waukesha County; and private well owners in Franklin and Oak Creek.
"That's a large group of folks," Nitschke said. "We continue to get samples in from people and ascertain that data and try to get answers out to those folks that test above the standard."
Residents whose wells show high levels of molybdenum can look into treatment options or alternative sources of water. The meeting Thursday offered stations on treatment devices; information is also available on the DNR's website. Molybdenum testing kits are available at the health department.