A team of University of Iowa (UI) researchers recently discovered high levels of polychlorinated biphenyls (PCBs) in the sediment of the Indiana Harbor and Ship Canal (IHSC) – a waterway connecting to Lake Michigan.

PCB exposure is linked to numerous health effects, including cancer.

This study followed-up on an earlier UI study, which determined that PCBs were being released from the sediment into the water and air. For the new study the researchers drilled into the sediment and found that the levels of PCBs were higher within the sediment than the measurements from the previous study.

These findings come prior a scheduled dredging of the canal, which could increase the toxin’s exposure. Dredging Today reports that UI researchers Keri Hornbuckle and Andres Martinez hope that the PCBs are taken into account while planning the dredging:

Hornbuckle and Martinez recommend that the PCB concentrations in the sediment be considered in the dredging strategy to reduce the potential release of PCBs into the environment.

“They need to dredge it, but I think they need to dredge it all,” Hornbuckle said. “If you were going to dredge it all, you would figure out where all the pollutants are and then you would remove them and move them somewhere safe. They don’t intend to dredge it all, because that would be much more expensive and disruptive to this very active harbor.

 ”It’s not the act of dredging that is the problem. The problem is when you leave contaminated chemicals at the surface that continue to be released forever.”

For more information on PCBs visit the Environmental Protection Agency’s website.