The Michigan Department of Health and Human Services (DHHS) on Wednesday hosted a webinar sharing the findings of its second report on PFAS exposure in northern Kent County. 

PFAS was detected in residential drinking water wells in parts of northern Kent County in 2016, with levels ranging from undetectable to over 50,000 parts per trillion. PFAS, also known as “forever chemicals” are a group of chemicals used to make nonstick cookware, water-repellent clothing, and products that resist grease water and oil. 

These chemicals break down very slowly over time, and have been linked to harmful health effects in humans and animals.

The Michigan Department of Environment, Great Lakes and Energy (EGLE) identified PFAS in private wells located near former waste disposal sites. EGLE later tied these contaminants to Wolverine Worldwide, a shoe manufacturer based in Rockford, which has disposed of waste from its leather tanning and shoe manufacturing operations.

Households were eligible to participate in the exposure study if they had a private drinking water well tested by or by instruction of EGLE, and had detectable levels of PFAS reported to DHHS by EGLE. 

While the first report, released in 2020, summarized the blood PFAS contents of participants, this second report focused on sources of PFAS exposure, looking at the relationship between PFAS concentrations in drinking water and the concentration of PFAS in the participants blood, as well as exposure to PFAS from other sources. 

In total, 183 households were selected to participate, and filtered and unfiltered water samples were taken from each household. 

Toxicologist Joost van’t Erve explained that most of the types of PFAS detected in participants’ blood could be detected in at least some level in the water samples collected.

While some homes were particularly impacted with high concentrations of PFAS, most of the households in the assessment had much lower levels in unfiltered drinking water samples, van’t Erve said. 

Filtered samples also showed much lower detection frequencies and concentrations of PFAS. Early in the presentation, van’t Erve noted that most people already had filters installed in their homes prior to joining the exposure assessment. 

In summarizing the assessment’s findings on PFAS concentrations in blood and drinking water, van’t Erve said higher concentrations of PFAS in the water was tied to higher concentrations in the blood. 

“It all comes down to really how much was that daily intake that you had? So it’s the combination of having PFAS in the well and then drinking more of that water that led to the highest amounts of PFAS in the blood,” van‘t Erve said. 

However, exposure to PFAS varied widely between participants, with researchers concluding that there were other sources contributing to PFAS in blood other than drinking water. 

NKCEA Second Report

 

Epidemiologist Rachel Long explained that older residents tended to have higher levels of PFAs than younger residents, which was consistent with findings in other studies.

“This is possibly because PFAS is bioaccumulative. It builds up in the body if you’re continuously exposed, and older individuals have been exposed to more PFAS before the use of certain PFAS was reduced in industry and consumer products,” Long said. 

Male participants also tended to show higher levels of PFAS in the blood than female participants. This is likely because males are not excreting PFAS as quickly because they do not excrete the chemicals through menstruation, pregnancy or breastfeeding, Long explained. 

While a greater number of births and menstruation within the past three years were tied to lower blood PFAS concentrations, these relationships were not found to be statistically significant. Similarly, while the number of total months female participants spent breastfeeding was tied to lower blood PFAS, with higher levels in the children being breastfed, this relationship was also not statistically significant. 

Eating wild caught fish was also tied to higher blood concentrations of three types of PFAS: PFOS, L-PFOS and PFBA. However, eating wild caught fish from within the study area was only associated with high concentrations of L-PFOS.

Consuming vegetables and wild game from within the study area was not tied to any effects on PFAS concentrations. 

Kidney disease was also tied to decreased levels of PFAS in blood, while diabetes was associated with higher levels of PFHpA, another type of PFAS.

“This was somewhat unexpected for kidney disease since decreased kidney function is something that we would expect would lead to decreased PFAS excretion and therefore higher PFS concentrations in blood,” Long said. “However, some participants reported ever having been diagnosed with kidney disease also reported having been on dialysis, and this could account for the negative correlation since dialysis is an excretion method.”

High frequency of blood or plasma donations were also tied to lower PFAS levels, Long said. 

Long also noted that working in industries that used PFAS was not linked to higher or lower PFAS blood concentrations. However, many of the participants who worked in these industries had either worked in positions where they would not have been exposed to PFAS, or had been in those positions far enough in the past to where PFAS would not appear in their blood, Long said, with participants working in positions where they could have been exposed leaving those positions by the late 1980s.

With northern Kent County residents exhibiting higher blood concentrations than the general U.S. population for five types of PFAS, van’t Erve outlined future steps DHHS is taking to examine PFAS exposure in the state. 

In 2020, DHHS launched the Michigan PFAS Exposure and Health Study, and North Kent County residents are invited to participate in the study’s final time point in 2025, van‘t Erve said, with the studying reopening for new and returning participants later this year.  

The state has also received funding from the Centers for Disease Control and Prevention to participate in a multisite study on PFAS and health components with six other states, van’t Erve said.