Dredging of a highly contaminated canal along the shore of Lake Michigan has begun, triggering fears among some experts that the project could release harmful chemicals into an Indiana community.

To dig a deeper canal for ships, the U.S. Army Corps of Engineers is removing large volumes of contaminated sediment – equivalent to about 160 million truckloads – from the Indiana Harbor and Canal.

The canal already contributes a significant amount of polychlorinated biphenyls (PCBs) to East Chicago’s air. And that load of pollution could skyrocket as the Corps dredges into deep sediment, said Keri Hornbuckle, a professor at the University of Iowa’s department of civil and environmental engineering.

“I’m not as worried about the dredging process itself, but what they could leave behind on the surface,” Hornbuckle said. “That’s the stuff that will get into the air.”

A new, as-yet unpublished study has found that indoor air in East Chicago, a low-income area inhabited almost entirely by Hispanics and African Americans, already has PCB levels about three times higher than its outdoor air.

For five decades, beginning in the 1930s, a now-defunct refinery discharged the chemicals, which were banned in the late 1970s, into the canal. Widely used as electrical insulators and industrial lubricants, PCBs have been linked to many health effects, including cancer, reduced IQs in children and asthma. 

The canal’s sediment is “among the most contaminated and toxic” ever reported, according to a 2002 U.S. Geological Survey study.

Connecting the Grand Calumet River to Lake Michigan, the Indiana Harbor and Canal is designated an “Area of Concern,” a term used by the U.S. Environmental Protection Agency for environmentally degraded sites in the Great Lakes basin.

In a $180-million project that will take eight to 10 years, the Army Corps will be removing 1.6 billion cubic yards of sediment from several feet below the surface, where PCB concentrations are up to six times higher than surface sediments, according to a 2011 study led by Hornbuckle.

“If the underlying sediment is twice as concentrated with PCBs as the surface sediment they’re getting rid of, then it’s likely the airborne levels will double” in East Chicago, Hornbuckle said.

Jennifer Miller, an Army Corps environmental engineer based in Chicago, said the Corps is continuously monitoring the air for petroleum-based compounds. In addition, air samples checking for PCBs and metals near the disposal site and dredging areas are collected every six days, and the results will be available a couple of months after that, she said.

Miller said there are “multiple viewpoints on whether a compound is considered non-volatile or volatile” and that high levels of PCBs and metals won’t be released into the community’s air.

But Hornbuckle said PCBs are readily transformed into a gas. The canal already emits about 15 pounds of PCBs into the air every year, according to Hornbuckle’s 2011 study.

Ron Hites, a professor at Indiana University’s School of Public and Environmental Affairs who specializes in air monitoring in the Great Lakes basin, agreed with Hornbuckle, saying PCBs on surface waters become airborne.

People are usually exposed through eating tainted fish, but PCBs can be inhaled, too.

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