HCMA assessing contamination at Kensington site

Contaminated soil was discovered last spring near the service area at Kensington Metropark, and since then engineers from the Huron-Clinton Metropolitan Authority (HCMA) — along with Fishbeck, Thompson, Carr, and Huber Consultants, Inc. — have been testing and preparing a final assessment of the site for the state Department of Environmental Quality (DEQ).

The contaminated soil was first discovered when three fiberglass underground fuel storage tanks were removed last spring. Since all three storage tanks were found intact, Mike Arens, chief engineer for the HCMA, said he believes the contamination was caused by other underground tanks that existed several decades ago.

According to Arens, the HCMA has found a number of volatile organic compounds within the soil causing contamination levels to be above those specified by the state’s drinking water standards.

However, it does not appear the contamination has reached the groundwater, according to Arens.

“We tested (the groundwater) at the time,” he said. “And we continue to test it to absolutely make sure the groundwater is not contaminated.”

Arens also said the contamination is “fairly localized.”

“We are looking at one area that may be about 30-feet-by-30-feet, if I had to guess. And another area that is about 40-feet-by-60-feet. As for the vertical extent (of contamination), we are still trying to ascertain (that). It looks like it goes down to a maximum of 40 feet below the surface, but we’re still trying to confirm that,” Arens said.

Regardless of the extent of contamination, the HCMA will have to undertake some sort of remediation. Arens said he believes they could utilize a combination of technologies including soil excavation with off-site disposal or soil vapor extraction — an advanced bioremediation technique.

While further treatment details are uncertain at this time, Arens said they will be finalized before the HCMA has to submit a final assessment to the DEQ on April 20. He said he doesn’t expect the treatment to be expensive as it’s not a major contamination site.

“It seems to be fairly straightforward,” he said. “We are always concerned about protecting our environment in the parks here.”