(Editor’s note: After local environmental activists questioned the original version of this story, we did a more thorough review of the report and presentation from the Fehr Graham study of the Prairie Lakes system and have revised the story to provide a more complete version of the study’s conclusions.)

The highly anticipated water quality study results for Prairie Lakes at the Izaak Walton Preserve showed that the water detention system is working properly but high concentrations of iron in a northwest pond exceed safe levels.

The study was presented to the Homewood Village Board at the Tuesday, Feb. 10, meeting.

Environmental Project Manager Matthew Drabik from Fehr Graham, an engineering and environmental services firm, shared the detailed process and assessment that was conducted over the course of a year.

Residents raised the alarm in 2023 saying the northwest pond at Prairie Lakes was being contaminated by the discharge from groundwater. They said the village failed to monitor the problem.

The village asked for an assessment from the U.S. Environmental Protection Agency and joined with the Izaak Walton Preserve to hire a consultant.

After a prelminary study found evidence of potentially toxic substances, the village agreed in May 2025 to hire Fehr Graham for a more complete $90,000 water quality study, Homewood Village Manager Napoleon Haney said.

The study determined that Prairie Lakes is not toxic, Drabik said, except for the iron content found in the northwest pond, which is the site local scientist Dave Zaber and South Suburbs for Greenspace advocates first cited as the source of the problem.

According to the report: “These iron concentrations make the water unsafe for human consumption and present potential acute toxicity risks for aquatic animals in the immediate vicinity. However, this process naturally occurs and is very common in wetland environments where the soil is saturated for most of the growing season.”

The wetlands are providing adequate filtering so the iron content is reduced to a safe level when it reaches the larger body of water to the east, Drabik said.

According to Drabik, water and sediment samples were collected throughout all seasons and types of weather from different parts of the lake.

Elevated iron levels were detected in several of the wetland areas, which contribute to the visible orange sheen. The sheen is caused by oxidation from “naturally-occurring iron bacteria,” and is common in the presence of sump pumps, Drabik said. The bacteria itself does not pose risks to humans, nor is it associated with any drinking water standards, he said.

The high iron content could be addressed, he said, by installing aerators and filters before groundwater reaches the lakes.

According to Drabik, there were some mercury levels traced after rainfall, which is unusual since that’s when it should be diluted and at its lowest, he said. However, since the amounts of mercury were considered low-level, it is not cause for concern. Continued monitoring is the only recommendation for that finding at this time, he said.

The next steps and targeted recommendations from the firm are to add educational signage to address public concern for the orange discoloration, as well as to add a “catch and release only” sign for fishing, Drabik said.

Environmental activists at the meeting still expressed concern over the elements that were found in the report.

Activist Liz Varmecky, founder of South Suburbs for Greenspace, said the high iron levels remains a concern.

The extent of the negative effects from the iron could affect fish, Drabik said.

“Around those wetland areas themselves, there would be issues for aquatic life, maybe reproduction or stunted growth because of that iron content,” Drabik said.

David Sacks, also a member of South Suburbs for Greenspace, expressed his concern over discrepancies that he perceived in the report.

“This report actually validates everything our group is saying, which is there’s an issue with the sump pump discharge coming from Homewood Disposal,” he said, adding, “and the number one thing we’re asking is to deal with the discharge.”

Homewood Disposal’s operation is not considered a source of the substances entering the pond, which come from groundwater. While some of the chemicals were in exceedance for ingestion levels, they are common in soils in urban areas, Drabik said.

“Do you believe there is a major toxicity problem in the north pond?” Homewood Trustee Lauren Roman said.

“No,” Drabik said.

“I hope the group feels some vindication,” Homewood Trustee Jay Heiferman said, adding, “I’m glad we’re moving forward and I hope we continue to make sure we follow the recommended steps.”