MILFORD, MI – A notice to avoid contact with the Huron River downstream of Wixom remains in place Monday as state officials weigh test results for toxic chemicals released from an auto parts manufacturing plant.
Testing revealed low detections of hexavalent chromium over the weekend in Kent Lake and Hubbell’s Pond, two impoundments on the river near Milford where state teams have focused efforts to find chemicals released there a week ago by Tribar Technologies.
Of 69 water samples taken from 42 miles of river over the past week by the Michigan Department of Environment, Great Lakes and Energy (EGLE), two showed positive detections at Hubbell Pond and one at Kent Lake.
At Kent Lake – which is surrounded by the popular Kensington Metropark, which offers beaches and boat rentals which remain closed until further notice – a sample tested at 5 parts per billion (ppb). That’s the detectable limit for the chemicals in the method the lab uses, EGLE said.
The sample was taken from the middle of the lake near the surface of the water, between 6 and 12 inches deep.
In Milford’s Hubbell’s Pond, detections were somewhat higher. The samples found 11 ppb of chromium on the surface and 9 ppb near the bottom.
In Michigan, hexavalent chromium is regulated in surface waters at 11 ppb and 16 ppb, which are set to protect aquatic life from chronic and acute exposures, respectively.
As of Monday morning, EGLE had not released weekend test results.
“EGLE tested dozens of other sites across the river system on Saturday,” EGLE spokesman Hugh McDiarmid said. “(The Michigan Department of Health and Human Services) and EGLE will review this data today to try to determine what this means.”
In addition to water sampling, the state has focused testing on biosolid sludge inside the Wixom sewage treatment plant. Officials speculate that the low detections in the river indicate the chemicals may have been largely contained within the fail-safe filtration systems of the sewage treatment plant and the Tribar plant, which sends its effluent through carbon filters.
A Wixom City Police investigation into the cause of the release at Tribar Plant No. 5 has been turned over to the state’s Environmental Investigation Service (EIS).
Hexavalent chromium, or hexachrome, is a carcinogenic chemical used in finishing plastics. It can cause many health problems through ingestion, skin contact or inhalation.
The state says any chemicals in the river are unlikely to pose a threat to water wells along the river because the chromium is not expected to enter adjacent groundwater. However, irrigation pumps and driven sand points could be vulnerable and should never be used for drinking.
The state sampled further downstream at Barton Pond, where the city of Ann Arbor draws some of its drinking water. The chemicals were not detected there, but the effort is also aimed at establishing a baseline data record.
The Huron River, which is impounded in several places, is not moving water at high speeds and computer modeling indicates that flow is not expected to bring hexchrome to Ann Arbor for several weeks, state officials said. .
Nonetheless, Ann Arbor officials are fed up with Tribar, and the city council authorized legal action against the company last week. Tribar, formerly Adept, is primarily responsible for the “do not eat” fish advisory in the Huron River due to PFAS chemicals. City council members and environmental activists have called for the plant to be closed and other punitive measures in response to the latest chemical release.
Like Tribar’s PFAS releases, which occurred for many years but were only discovered in 2018, the hexchrome was sent to the Wixom sewage treatment plant. The facility sends treated wastewater to the river via Norton Creek near the Proud Lake State Recreation Area.
Tribar released a statement on Thursday saying it responded with “immediate” action after discovering the release of hexchrome on August 1, although the city of Wixom says the chemicals have started flowing into its system. sanitation last weekend.
According to a letter of demand sent by city officials to Tribar, the company sent approximately 10,000 gallons of toxic, untreated sewage to the city “over the weekend of July 30, 2022.”
The city limit for hexachrome in wastewater is 0.44 parts per million (ppm). Tribar’s release far exceeded that. The letter says Tribar “released approximately 4,170 pounds in 48 hours” with concentrations of 95 to 130 ppm. The treatment plant first tried to contain the discharge by diverting it to a holding tank and a ditch. But the staff started sending him back to Norton Creek once those were full.
In plating companies like Tribar, hexachrome is used to coat the decorative trim parts of automobiles. Due to its toxicity, it is banned in Europe and many surface finishing companies have phased out its use in favor of less toxic chemicals.
Encouraging tests, but concern and anger remain
River tests show no hexchrome, says EGLE
Hexchrome could take weeks to reach Ann Arbor
Ann Arbor OK Council Lawsuit Against Tribar
Wixom Police Investigate Hexachrome Tribar Spill
No contact with Huron River requested after spill