Back in April, Kory Groetsch with the Michigan Department of Health and Human Services, speaks to a packed room at Otsego United Methodist Church. (File photo)

Otsego’s water is safe despite trace dioxins

Ryan Lewis, Editor

Otsego’s municipal water has been given a clean bill of health despite a trace amount of highly toxic dioxins.

Otsego city manager Aaron Mitchell late last week announced the results of a recent round of extensive testing of the city’s three operating wells by saying the city now knows what is in the drinking water.

“I believe the testing we have gone through has been more rigorous than any municipality in the state,” Mitchell said. “And after all of that testing, we know that Otsego has clean drinking water.”

The city tested its water in unison with a Michigan Department of Environmental Quality effort to test dozens of residential wells in the surrounding area. That effort bloomed from public outcry over suspicions of increased cancer rates from decades-old contamination from the paper mill industry.

While final results of that testing are still pending, preliminary results showed some levels of some dioxins in 17; those homes are currently receiving bottled water.

According to the U.S. Environmental Protection Agency, dioxins can cause cancer, reproductive and developmental problems, damage to the immune system, and can interfere with hormones.

A Tuesday press release said, “After reviewing the test results, the Michigan Department of Health and Human Services has determined there is no health concern regarding these chemicals in City of Otsego water.”


0.0992 picograms

Mitchell said testing detected no dioxins in two of the three city wells.

In the third, he said state agencies calculated the “toxic equivalency,” or TEQ, of what was detected at 0.092 picograms—“So: very, very small.”

That number was a calculation state toxicologists made, based on the different toxicity levels of the 29 types of dioxin-like chemical included in the test. The calculation method has been designed by international experts, adopted worldwide and vetted by the U.S. National Academies of Science.

The state press release said, “MDHHS concludes that 0.092 ppq-TEQ does not represent a public health hazard.”

That agency said the trace amount was more than 100 times lower than 12 ppq—or, parts per quadrillion—the level understood to still be safe for anyone—pregnant women, children, or adults—to drink daily over their lifetime and not expect harm.

Kory Groetsch, environmental public health director at Health and Human Services, said, “We’re being very thorough. And if you tested like this everywhere, I would not be surprised if you found detections like this or more in most locations.

“It’s as close to nothing as is really expected.”

While as much as 12 ppq was considered safe, levels higher than that would simply warrant more research and concern. At 30 ppq, state and federal agencies would step in to take action.

Groetsch said, “Being above 12 ppq doesn’t mean you’ll be harmed, but being below it we feel there’s a solid margin of minimal risk.”

In fact, he said both numbers were significantly conservative estimates for measuring public health danger.

To put Otsego’s 0.092 picograms in perspective, here are some other measurements related to recent contaminants being dealt with in the area:

• 50 parts per million—this was the measurement of the carcinogen PCB (another paper mill byproduct) the EPA used to determine whether contaminated soil dug out of the Kalamazoo River floodplain and riverbank needed to be trucked to special, sealed landfill. Any sediment with fewer than 50 molecules of PCB per million molecules of water could be disposed of in a standard landfill.

• 70 parts per trillion—this was the danger threshold EPA set for PFAS, the group of chemicals that made local headlines after high concentrations were found in Parchment’s municipal water. In early August, Otsego’s city wells measured at 11 ppt; that’s a ratio of 11 molecules of PFAS for every trillion molecules of water.

• A picogram is a one-part-per-quadrillion measurement; that’s a 1 followed by 15 zeros. A quadrillion is 1,000 trillions.

Mitchell said that when the measurements were being described for the PFAS testing, 1 ppt could be thought of a bit like a single drop of water in 20 Olympic-sized swimming pools.

“So, this would be like a drop of water in 20,000 swimming pools,” he said.



Mitchell said city employees drew the water samples Sept. 6 for the main battery of tests that would be used to search for approximately 300 chemicals. The city does not filter the water but does chlorinate and conducts regular testing, as required by state and federal laws.

“We wanted it to be exactly as what’s being tested for in the township,” Mitchell said. “We’re doing that so we can make apples-to-apples comparisons.”

More samples were taken last week so the city could test for another dozen more exotic substances the DEQ added to the list of tests out in the private wells.

“It’s for stuff that has never been tested for in our drinking water,” he said. “All of the township wells were negative (non-detect) for them and we’re expecting to be negative as well. They’re not dioxin related.”

Each round of testing will end up costing the city approximately $4,000. Pace Analytical tested the samples.

“We’ve paid for all of this and paid to expedite the results,” Mitchell said. “Cost isn’t really a concern right now.”


What’s next

Next steps for the city depend largely on water testing results from Otsego Township and the City of Plainwell.

“We can actually feed into each other’s system if we need to,” Mitchell said. “It’s not as easy as flipping a switch. But, if catastrophe comes, it’s simpler than having everyone on bottled water.”

He said the DEQ had studied the issue and said the city had capacity to add the other municipalities. That basically involved opening a series of valves, but that was complicated by several concerns.

Being able to pump the water properly through the system and maintain the proper water pressure might require adding some booster pumps. Also, if there was contaminated water in the system, it would need to be flushed completely out, and that process came with a variety of challenges.

Other than that, plans that had been on hold to drill a new well would likely be going forward now. That would replace a 40-year-old well that had been pumping slower than its original capacity. That was expected to simply be drilled nearby the one it is replacing. All three city wells are near Brookside Park.

“We’re watching the residential well investigation,” Mitchell said. “But as far as additional testing, we’ve been told we’re good to go.”

In the announcement last week, he thanked residents for their patience as everyone awaited the testing results and said, “MDEQ is still continuing to do additional methodology validation with the laboratory, which could take some time, but they are confident the 0.092 ppq-(toxic equivalency) result will not change.”

Residents with questions can call city hall or the Allegan County Health Department’s Hotline (269) 686-4546 from 10 a.m. to 6 p.m.

Contact Ryan Lewis at or (269) 673-5534.


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