KALAMAZOO, MI — A toxic chemical that flowed into the city of Kalamazoo’s wastewater treatment plant was the highest concentration of the contaminant ever seen at the plant, Public Services Director James Baker said. The incident did not affect the city’s drinking water, Baker said. Still, it caused issues for the city’s wastewater system and sparked concerns that remain weeks later. In late March, the Kalamazoo/Battle Creek International Airport spilled firefighting foam that entered the city’s wastewater treatment plant. The firefighting foam spilled contained one of the toxic “forever chemicals” known as per- and polyfluoroalkyl substances, or PFAS, and was measured leaving the city’s plant at concentrations far above state standards. PFOS, a type of PFAS found in the foam, was measured at 28,550 parts per trillion where water enters the plant. Baker provided measurements to MLive that show the plant’s effluent, or water flowing out of the plant post-treatment, was measured at 2,630 ppt on March 31. That concentration is more than 200 times greater than a national water quality standard of 12 ppt. “The treatment plant did a great job treating it, it was just overwhelmed,” Baker said, “There’s only so much we can do.” Those levels were orders of magnitude higher than what the plant saw when an industrial location in Richland was releasing PFAS in 2018, Baker said. An updated effluent test on April 9 came back with a finding of PFOS at 301 ppt. Because it was above the standard, the effluent release was a violation of the plant’s National Pollutant Discharge Elimination System permit, the city said. The city document also shows 357 ppt of PFOS was measured at the Kalamazoo River. While two other sample locations in the river had lower numbers, they were still above the limit of 12 ppt. The city also provided testing results for PFOA, which showed up in amounts below the regulatory threshold of 1,200 ppt, a document provided by the city shows. The city of Kalamazoo provided the results of samples tested for the presence of PFAS. The concern is for the river, Baker said in an interview with MLive last week. “Certainly we consider ourselves stewards of the river where we work every day to help protect that river,” Baker said, and they are also concerned about the environment. The city’s wastewater plant contains a biological process, Baker said. The plant creates an atmosphere of oxygen, nutrients and microorganisms such as bacteria and fungi that eat waste. The city will monitor the approximately 12-day lifecycle of the organisms after the PFAS spill, Baker said. When their natural lifecycle is over they are “wasted” and a new generation of the organisms are introduced, he said. The wasted microorganisms end up in a landfill, he said. The city has taken samples for the PFAS chemicals in the river, shipping samples to a lab in California for analysis, he said. The city has oversight of the sewer system and the city can require users to take actions if needed, Baker said. The practices at the airport will likely have to change because of the incident, Baker said. “We can make recommendations, and ultimately, we can control who discharges to us and who doesn’t,” Baker said. Following the spill, the airport was examining its practices and making some changes, Airport Director Craig Williams said last week. Initially, the airport placed a zip tie on the PFAS valve in hopes of preventing a future incident. Airport officials were also examining other practices to see if any improvements could be made. Baker said additional changes will probably be needed at the airport. He said the city has a better handle of what is going on at places labeled “significant users” of the system, which are subject to at least annual inspections by the city. The airport is not considered a significant user, he said. Baker and Williams both said they were glad the spill did not enter the groundwater in the area. The spill at the airport in Kalamazoo came after EGLE, in cooperation with the state fire marshal’s office, in 2020 collected more than 30,000 gallons of toxic fluorochemical foam from municipal fire departments and commercial airports across the state. The effort was part of a voluntary foam disposal program. PFAS are nicknamed “forever chemicals” for their ability to resist degradation over time. They are considered harmful at the very low parts-per-trillion (ppt) level if consumed in drinking water and, over time, can cause serious health effects.