Researchers find DDT byproduct in Lake Calumet herons

Illinois' endangered black-crowned night herons have picked up trace amounts of DDT byproducts, even though the insecticide was banned in the 1970s.

Researcher Jeff Levengood of the Illinois Natural History Survey is the lead author of a study that found the herons' tissues contain DDE -- a toxic byproduct of DDT.

The amount is too small to cause problems. But its presence shows how enduring the compound is in the environment.

Black-crowned night herons stand about two feet tall, and are stockier than other herons. They nest in marshes on Chicago's Southeast Side, near Lake Calumet.

Chicago Environment Commissioner Suzanne Malec-McKenna says cleanup of the Lake Calumet wetlands is under way. But it won't reduce by much the levels of the DDT byproducts in the marshes.