Environmental Progress - Fall 1998

Here a Fish, There a Fish... Chicago River on the Mend

Minnows to madtoms, fish increasingly like the stream

A funny thing has been happening recently around the Chicago River; people are asking if it's safe to eat the fish.

The strange thing isn't what they're asking; in many cases the answer is "probably not." What's exciting is that they're asking at all. In the Chicago River, anglers are once more catching fish, fish that haven't been seen there in years. In fact, there have even been fishing tournaments on the banks of the Chicago River the last two years. A native madtom was reportedly snared in the Chicago River recently, a single example of a genus that has never been seen there before. Along the mainstem and various river branches more than 50 species are being identified including some, like the endangered Iowa darter, that tend to disappear when pollution levels rise and which for years had been absent from the Chicago River.

A sampling program begun last year and scheduled for follow up this summer evaluated carp, bass, bluegill and sunfish taken by the state Department of Natural Resources at four locations along the Chicago River. Not surprisingly, given the river's history as a conduit for treated and sometimes untreated waste, some samples contained elevated levels of PCBs and the termite treatment chlordane as well as other banned pesticides. The 1998 sampling is likely to confirm the presence of those contaminants. If that happens, an advisory probably will be issued similar to the advisories already in place on Lake Michigan fish.

In late April, Illinois EPA toxicologist Tom Hornshaw appeared before a Chicago City Council committee to discuss the changing fish scene.

"We want to see if the small fish are as dangerous as the large fish," Hornshaw said. "Then we'll be able to make some decisions on the acceptability of the fish, especially carp, for eating once a week or once a month, whatever is indicated."

Improvements in the Chicago River are linked to several causes. The Water Reclamation District's program of aeration stations feeds oxygen into the Sanitary and Ship Canal. The Deep Tunnel project has diverted billions of gallons of untreated sewage that previously overflowed into the Chicago River during storms. In the last two decades, levels of ammonium nitrate in the river have been reduced by half.

Programs that regulate end-of-pipe discharges from waste treatment plants and industries have reduced contaminants in many Illinois streams. A new emphasis on nonpoint source pollution runoff from parking lots, streets, lawns and farm fields is expected to cut back on siltation and pollution carried by this generalized runoff.

It's too early to stock up on lemons and tartar sauce, but the evidence is that the Chicago River is once more providing a home to fish that haven't been seen there in a long while.