Pall cleanup can be hidden

News Staff Reporter

A state-proposed network of pipes and extraction wells for cleaning up groundwater contamination under western Ann Arbor can likely be placed all underground, with few visible signs a cleanup is taking place, officials said.

But well-drilling and laying pipes would still cause some temporary disruption to neighborhoods, officials acknowledged at a public meeting Wednesday night.

Still, that cleanup option - a network of pipes and wells in westside neighborhoods - is the best technical solution for purging polluted groundwater, an independent expert said.

Larry Lemke, a geoscientist and environmental engineer who volunteers with Michigan State University's Technical Outreach Services for Communities, added that the state Department of Environmental Quality's plan was still lacking, however, and said the state needs to create a detailed model of the plume. That will show where the plume could best be intercepted, thus minimizing potential disruption to neighborhoods. He also recommended addition of more monitoring wells to ensure the plume was being captured, and more extraction wells west of the city.

"I think it is worth the wait," he said. "Ideally, you like to pump and treat as little (contaminated water) as possible. That way, there's less neighborhood disruption."

That did not sit well with some westside residents at the public meeting, which was sponsored by TOSC, the city of Ann Arbor and Scio Residents for Safe Water.

Residents said they still don't like the state's plan to clean up the plume with a network of pipes and wells through their neighborhoods.

"When Larry talks about more (monitoring) wells, where are those?" said Pat Ryan, a resident who lives near one of the DEQ's proposed extraction wells. "In the neighborhoods."

"We're talking about more wells without the prospect of anything that's definitively effective," she said. "We're really being greatly burdened here."

"I think the unknown here is what really bothers people," said Liz Workman, a resident near Jackson and Worden. "I think it would be helpful to know ... what exactly are we talking about here?"

Mike Gebhard, of the Washtenaw County Department of Environmental Health, said the pipelines could be double-walled to help contain a spill. And the pipes, even the extraction wells and pumps, could all be housed under ground, he added.

The plume of contaminated groundwater emanated from the Pall Life Sciences facility on Wagner Road. The company's previous owner disposed of wastewater that contained 1,4 dioxane, a solvent it used to manufacture medical filters, by storing it in unlined lagoons and spraying it over grounds. In the mid-1980s, dioxane turned up in local ponds and wells.

It has since migrated east of Wagner and in 2001 was discovered to have contaminated a low-lying aquifer that a west-side city well is tapped into. The well was taken off-line and the municipal water supply is not contaminated, according to city and DEQ officials.

But the contamination in that aquifer extends below the city under dense neighborhoods around and east of Veteran's Park.

The company submitted its own proposal earlier this year as well. Lemke said Pall's proposal, which includes continued pumping and treating at the company's Wagner Road facility, additional pumping from Maple Village Shopping Center and dealing with the rest of the plume when it reaches the Huron River, was "a gamble."

It would delay the cleanup and risk letting the plume fan so far out it would be harder to get under control. And some township "islands" near the river, farther east, still rely on well water, he added.

The DEQ will decide on its final proposal by Sept. 1. But a circuit court judge presiding over the cleanup could overrule DEQ's decision when Pall and DEQ next go before him Sept. 8.

Pall has pumped and treated more than a billion gallons of groundwater since the cleanup began in 1997.

Tracy Davis can be reached at tdavis@annarbornews.com or (734) 994-6856.

© 2004 Ann Arbor News. Used with permission