DUBUQUE COUNTY — Canadian Pacific Railroad is nearly done with cleanup and environmental monitoring after a Feb. 4 train derailment north of Dubuque spilled ethanol into the Mississippi River.
The derailment, still under investigation by the Federal Railroad Administration, caused three tank cars carrying ethanol to start fire and three others to slip onto the frozen river.
Railroad officials removed ethanol from 15 derailed tank cars, but some of the fuel drained into nearby soil and water. Ethanol degrades quickly in water, unlike oil, which emulsifies into tar balls or sticks to shorelines and river floors. But ethanol also can deplete oxygen dissolved in the water, hurting fish and other aquatic life.
Canadian Pacific worked with the Iowa Department of Natural Resources, U.S. Fish & Wildlife Service and the U.S. Environmental Protection Agency to set up 40 monitoring sites along the Mississippi River and on a tributary near the crash site.
The railroad checked the sites for ethanol and four other chemicals — benzene, ethylbenzene, toluene and xylene, said Chris Gelner, an environmental specialist in the DNR’s Manchester office. The sites also monitored dissolved oxygen.
Daily tests showed ethanol and benzene levels at the derailment site were higher than the screening standard in the days following the derailment, Gelner said. When further tests came back negative, the group shifted to weekly water monitoring.
Water testing on the tributary showed higher levels of ethanol immediately after the crash, but it tapered quickly, Gelner said.
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The DNR worked with the National Oceanic and Atmospheric Administration to create a model showing how fast the pollutants could have moved downriver. Through that model, the group also tested for chemicals near Muscatine, Gelner said.
“All of that indicated no presence at Muscatine,” he said.
Throughout testing, dissolved oxygen levels were normal, Gelner said. The DNR saw no fish kills, which can happen when dissolved oxygen levels get too low. Canadian Pacific has done a survey of mussels in the river, but the DNR doesn’t have the report yet, Gelner said.
On land, the railroad excavated and removed contaminated soil near the crash site, replacing that with clean fill, Gelner said. A final report on the cleanup is expected by summer’s end.
“Canadian Pacific has actually done a very nice job,” Gelner said.
An estimated 70 percent of ethanol shipments are done by rail in the United States, which would mean there were 340,000 railcar shipments of ethanol last year, according to the Renewable Fuels Association. Most shipments happen without incident.