EAST CHICAGO | Children here already have significant amounts of polychlorinated biphenyls -- PCBs -- in their bodies, and researchers want to find out just how much more will accumulate when the Indiana Harbor and Ship Canal is dredged.

Scientists with four major universities have been measuring concentrations of the toxic and carcinogenic chemical in the blood of participating West Side Junior High School students and their mothers since 2006 in anticipation of the dredging, now scheduled to begin in 2011.

"We're here because of the dredging," said David Osterberg, a researcher with the University of Iowa. "There are very high levels of PCBs in the canal, and when they are dredged, there will be very high levels in the disposal facility."

The U.S. Army Corps of Engineers plans to remove some 4.6 million cubic yards of polluted sediment from the harbor and canal, and permanently store the material on a 275-acre former refinery site just 800 yards from Central High School and West Side Junior High.

Banned in the United States since 1977, PCBs typically enter the body by eating fish caught in contaminated waterways.

But the man-made substance also shows up in the bodies of those who never eat fish, and researchers think that the chemical, which readily evaporates when exposed to the air, could be ingested simply by breathing.

For four years, scientists have been collecting air samples taken in the students' homes, at Central High and along the canal for comparison with a similarly sized community in eastern Iowa that has no known sources of PCBs.

Dubbed AESOP -- Airborne Exposure to Semi-volatile Organic Pollutants -- the study is sponsored by the National Institute of Environmental Health Science and combines resources of the University of Iowa, University of Illinois at Chicago, University of Illinois at Urbana-Champaign and the University of Kentucky.

"People in East Chicago are very interested in what we're doing," said Jeanne DeWall, study coordinator. "They're concerned about the dredging."

Though Osterberg said the data from the 112 mothers and children participating in East Chicago are "very preliminary," the amount of PCBs in the blood of the comparison group in Iowa appears lower than in the city.

"Generally, we're seeing what we expected," Osterberg said. "Mothers in East Chicago have higher blood concentrations of PCBs than their children, and in some cases, a lot more." The U.S. Department of Health and Human Services has determined that exposure to PCBs can cause cancer of the liver and biliary tract, and the chemical has been linked to problems with motor skills, a suppressed immune system and a decrease in short-term memory in children.

"We expect that both airborne and blood levels of PCBs in East Chicago will be higher once the dredging starts," Osterberg said.

In the meantime, researchers are continuing their efforts to educate the community about chemicals in the environment and their effects.

"We've taught more than 400 kids, starting with seventh-graders, about PCBs," said Dr. Victoria Persky, an internist at UIC and community outreach leader for the study. "It's been a rewarding four years."

Osterberg said he's confident the National Institute of Health will fund the research project for another five years, and plans to have more air monitors in place when the dredging actually begins.

Nancy Morales, a registered medical assistant and phlebotomist, said she's getting ready to collect the air monitors and visit residents again for their end-of-year blood samples.