Fish kill still raising questions

A large catfish rest on the steps near the lower dam in Rock Falls Monday. (Philip Marruffo/pmarruffo@svnmail)

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A week after droves of fish began to surface on the Rock River, gasping for air – and a week after thousands of fish subsequently died off – residents and officials alike still have more questions than answers.

Speculation that the fish kill was tied to a train derailment and ethanol spill in Rockford has abounded.

Officials said early in the week that the two events appeared to be linked. Still, they wanted to wait for the results of an analysis of water samples taken from the river to be sure.

When those results arrived, though, officials could find no link between the kill and the derailment – there was no ethanol in the samples, they said.

Friday, the same officials said those results don’t necessarily rule out ethanol as the cause, though. The ethanol may have been diluted by the time the samples were taken.

So was it the ethanol or wasn’t it? If it wasn’t the spill, what killed all those fish? If it was the ethanol, why did dead fish start popping up so far south of the derailment site? How many fish were killed, and how long might it take the Rock to recover?

It might be weeks, if ever, before those questions are answered.

Here’s what we know so far:

June 19

At about 8:30 p.m., a train loaded with 55,000 to 75,000 gallons of ethanol derailed in Rockford.

The crash sparked a daylong fire. “Most” of the ethanol burned up at the scene, but “an undetermined quantity of the product flowed into an unnamed creek that leads to the Rock River,” U.S. Environmental Protection Agency spokesman Mick Hans later said.

June 21

Anglers began to report fish behaving strangely: Catfish and carp were leaping onto the banks and laboring to breathe.

The Illinois Department of of Natural Resources advised the public not to eat fish from the river until the cause of the kill was determined.

The EPA began to collect water samples from the scene of the derailment and from areas along the Rock where dead fish were found.

Monday

Hans said the cause of the kill appeared to be the ethanol spill.

Tuesday

Biologists from the U.S. Fish and Wildlife Service, who also were working on the river, said the fill kill was over and it was now safe to eat fish caught in the Rock.

A definitive link between the derailment and the fish kill could not yet be made, but an analysis of the water samples would be completed soon, the EPA said.

IDNR representatives announced the boundaries of the kill. They said dead fish started showing up just north of Grand Detour and were found as far south as Prophetstown. They couldn’t explain why the kill would have started so far south of the spill site.

Thursday

The EPA said it couldn’t find a link between the derailment and the kill. The water samples taken 2 days after the spill didn’t contain any ethanol or its constituent chemicals, officials said. The agency returned its focus to the scene of the derailment.

bAn IDNR biologist said the agency had conducted autopsies on “a few fish that were fairly fresh” from the kill. “We’ve seen physical damage on the fish and on their tissue,” Wayne Herndon said. The tissue of the fish – mainly gill tissue – had shrunk, he said, through “contact with some substance.”

The EPA clarified: “The sampling effort has not ruled out the possibility that a now-diluted plume of ethanol was present prior to June 21,” Hans said. In other words, ethanol may have killed the fish but, by the time biologists got out there to take water samples, the ethanol had been diluted and washed downriver.

The Illinois Department of Public Health also clarified: While the agency “does not recommend restrictions on the consumption of fish ... IDPH does warn the public of the risk of increased bacteria levels in river waters from decomposing fish ... [and] urges the public to avoid water contact activities ... until the decomposition process is complete.”

So, you can eat the fish, but don’t go in the water to get it.

EPA officials said they were still in the “emergency-response phase” at the derailment site, excavating contaminated soil and testing public water sources. Further investigation into the fish kill will not come until after that phase ends, they said.