MASON CITY, Iowa (AP) — Officials are investigating two fish kills in north central Iowa.
The state Department of Natural Resources says it began looking into the fish kills Monday. They’re located in Kossuth County on the east fork of the Des Moines River and Boone River in Hamilton County.
Officials are still looking for the source of pollution. In Kossuth County, the pollutant turned the east fork of the Des Moines River green, west of the town of Irvington. Staff reported low oxygen levels and a chemical odor.
In Hamilton County, the contaminant killed fish and other aquatic organisms along a stretch of the Boone River southwest of Woolstock.
Officials say it’s not likely that manure caused the fish kills, since staff did not detect ammonia at either site.