GRAND RAPIDS, MI -- A cancer study of residents from northern Kent County who may have been exposed to hazardous chemicals from Wolverine World Wide's hazardous dump sites may not yield conclusive results, according to health officials.
It will be difficult, health officials say, because of the relatively small population affected.
The study has been in the development stages for months as local health authorities work with state and federal agencies. The Kent County Health Department now expects to launch the study in mid-fall -- about a year after its launch in September 2017.
"It's really important that we do it right," said Adam London, health officer for the Kent County Health Department.
Pressure to conduct a cancer study came in fall 2017 as a growing list of residents in the Rockford area had their drinking water test positive for per- and polyfluoroalkyl substances called PFAS, (also called perfluorinated chemicals, or PFCs). The residents, who live near a property on House Street where Wolverine World Wide dumped tannery waste containing PFAS in the 1960s, also reported cancer and other illnesses.
Exposure to PFAS has been linked in human studies to some cancers, thyroid disorders, elevated cholesterol and other diseases.
The health department had drafted a survey in late 2017 and was preparing to launch it in March 2018. That initial effort stalled after the U.S. Centers for Disease Control and Prevention got involved in December to guide the effort.
"We could have quickly pulled together a survey that would have been a waste of time, and would not have provided any actionable data," London said. "But really, we've been focused on doing it right. I feel bad that it's taken a long time."
However, the number of people eligible for the cancer study in Kent County is too small to yield statistically significant information about cancer rates, London said. There are more than 100 drinking water wells within the proposed study area with levels of PFOA and PFOS higher than the U.S. Environmental Protection Agency's Lifetime Health Advisory of 70 parts per trillion, according to the health department.
"It's just hard with numbers that small when you're trying to pick up and detect different rates of cancer," London said.
It's been a point of contention for the health officials from the county, state and the CDC.
"We all struggled with it," London said. "There were a lot of people that looked at the size of population there and said, there's no way you're going to get any conclusive information from a group that small."
London said there is still value to the study to document the health effects on the residents who have been exposed to some of the highest PFAS levels in the country.
"There is a portion of this group that have been exposed to levels that have not been seen other places," London said. "There's value in and of itself in having a profile of the health in this area so we can compare it to other areas."
Data from the Kent County survey will eventually be combined with eight other studies across the country in communities yet to be announced, London said.
"Hopefully, when you combine all this data there will be enough there to draw some conclusions," London said.
Hard details of the study are still being determined, including the geographic area that will be surveyed and the number of individuals involved, London said. The Michigan Department of Environmental Quality hasn't been able to link four neighborhoods in northern Kent County with low levels of PFAS in private wells to Wolverine World Wide.
"It's difficult right now to draw a line around a boundary of contamination," London said. "Those things will become defined as the summer progresses."
Officials also have not yet decided if individuals who have moved away from the area should be included. The cancer study will likely include a blood test for at least some of the individuals, London said.