The city of Ann Arbor has detected very low levels (0.039 parts per billion) of 1,4 dioxane in its drinking water for the second time.
Similar levels (0.030) were found about one year ago.
The city tests its drinking water monthly.
According to city officials, the curent detectable levels in the city's drinking water are not considered a health risk.
"They're very, very low," said Brian Steglitz, Ann Arbor's water treatment services manager. "And well below, over ten times lower than the EPA identified risk level."
Steglitz said the city is not sure the tests are even accurate because the samples may have been contaminated in the collection, transport, or testing. Steglitz said Ann Arbor has already done some retesting and the results should be available within one or two weeks.
"We try to be transparent with all of our data and information," Steglitz said. "But we also want to make sure that people are not getting concerned about something that is really not, at this point, a health issue."
Steglitz said it is not possible to know the source of the recently detected very low levels of 1, 4 dioxane. He said it could be from small upstream wastewater treatment plants, or it could be from Gelman Sciences' treatment plant's discharge into Honey Creek.
Gelman is responsible for dioxane pollution in part of Washtenaw County.