Environmental Risks & What We Can Do?

The Huron River is the source of the municipal drinking water for almost half of the residents of Washtenaw County.

On this page is data about two major environmental risks to Washtenaw County residents: 1,4 Dioxane and PFAS, which are cancer causing substances which have been present for many years in the municipal water supply of the City of Ann Arbor.  Residents of District 2 including those who work or reside in the City of Ann Arbor and parts of Ann Arbor Township are directly at risk of exposure to these toxins. I also discuss what we should do about these risks.

The Danger from 1,4 Dioxane

1,4 Dioxane is a cancer causing toxin that has been contaminating our municipal water supply since March 2019: https://www.mlive.com/news/ann-arbor/2019/03/dioxane-detected-in-ann-arbor-drinking-water-from-barton-pond-for-first-time.html

A large plume of 1,4 Dioxane has been spreading out in the aquifer on the west side of Ann Arbor for decades. Experts have been warning that the plume will spread to the Huron River and contaminate the municipal water supply of the City of Ann Arbor if we don’t act. New well testing by Scio Township using the best available testing method indicates that the 1,4 Dioxane Plume is now just 1,000 feet from the Huron River, upstream from Barton Pond.  Barton Pond is the source of 85% of Ann Arbor’s municipal drinking water.

It’s what I’ve been warning about for decades.  So depressing.

Despite the fact that the main plume has not yet reached the Huron River, 1,4 Dioxane has been detected intermittently in the Huron River at Barton Pond over the last few years.  Experts surmise that it is because the current treatment system, O3O2, has as its output water, 1,4 Dioxane & another cancer-causing substance called bromate.  This 1,4 Dioxane and bromate tainted water is being dumped into Honey Creek, which is an upstream tributary of the Huron River above Barton Pond.

What should we do?

The treatment system should be changed to a state-of-the-art UVOx system, which reduces the byproducts to 100% safe carbon dioxide (fizzy water).  Once a safer water treatment system is in place, the amount of water being pumped and treated should be tripled, according to the experts I’ve talked to.  This might stop the spread of the Plume. More monitoring wells need to be put into place to give us more advanced warning if the Plume spreads further in any direction. Lastly, the testing method being used by Washtenaw County’s Health Department and the Michigan DEQ needs to be switched to the state of the art, more sensitive method being used by Scio Township in its well testing program.

1,4 Dioxane can pass through unbroken skin; 1,4 Dioxane poisoned water is unsafe to bathe or swim in.  

The Danger from PFAS

The Huron River also is contaminated by PFAS, another serious toxin.  PFAS is a cancer causing toxin that has been present in Ann Arbor’s municipal water supply since at least March 2014: https://www.mlive.com/news/ann-arbor/index.ssf/2017/06/ann_arbor_responds_to_concerns.html

The EPA believes that statistically cancer deaths begin to occur with long term exposure to concentrations of 1,4 Dioxane of 3,500 parts per trillion, while PFAS statistically causes cancer deaths with long term exposure to concentrations of 7 parts per trillion.  So, PFAS is 500x more dangerous than 1,4 Dioxane.

“PFAS” are a class of chemicals used in many kinds of products, like Telfon, food wrappers, Scotchguard and fire fighting foams. Michigan has almost 100 sites of known groundwater PFAS contamination.

The fact that PFAS are so common is frightening because these chemicals are associated with serious health risks, including some forms of cancer, high cholesterol, and thyroid disease. (Footnote #2)

The Huron River in Ann Arbor, where the city draws most of its drinking water, has seen rising levels of the toxic PFAS “forever chemicals”.  Tests of Barton Pond water samples showed four readings between 15.6 and 20.9 parts per trillion in May 2020, then increased each month to reach 58.4 ppt by December 2020.  The city uses carbon filters at its water treatment plant to remove some of the harmful chemicals, but PFAS still ends up in the water delivered to city residents and businesses — the raw water had between 13.4 and 34.7 ppt in the tests during 2022.  The treated drinking water has had PFAS at unsafe levels of between 7.2 and 25.9 ppt in the tests during 2022.  (Footnote #3) The PFAS pollution was traced to an industrial plant in Wixom.

What to do?

Additional state of the art filtration systems need to be installed to lower the level of PFAS in the municipal drinking water supply.

Homeowners should install state of the art filtration systems to lower the level of PFAS in their tap water.


1. “In Ann Arbor, a sample collected from the city’s finished water reservoir on March 5, 2014, detected PFOS at 43 ppt. Last year [2017], PFOS was detected on March 28 at 11 ppt in the reservoir and at 19 ppt at the Barton Pond intake.” See: https://www.mlive.com/news/ann-arbor/index.ssf/2017/06/ann_arbor_responds_to_concerns.html “Ann Arbor responds to concerns about toxic PFCs in drinking water”, June 9, 2017

2. “PFAS Response / Health,” Michigan Department of Environment, Great Lakes, and Energy, last accessed August 3, 2020. FAQ List: https://www.michigan.gov/pfasresponse/0,9038,7-365-86704_86677—,00.html

3. PFAS Test results from the City of Ann Arbor are available here: Raw Water Tests: https://www.a2gov.org/departments/water-treatment/Documents/PFAS-forweb-RIVER-062922.pdf, Treated Drinking Water Tests: https://www.a2gov.org/departments/water-treatment/Documents/PFAS-forweb-RESERVOIR-062922.pdf.