The Department of Natural Resources is investigating a fish kill that happened in Siouxland.
According to officials, the fish kill began on the North Fork of the Floyd River, about seven miles northeast of Sheldon in O’Brien County.
A resident reported the fish kill late Saturday.
On Sunday, DNR staff found dead fish starting close to the intersection of the North Fork and the Floyd River, and continued for four miles downstream.
DNR specialists have not yet identified the pollutant source.
Field tests show water in the North Fork of the Floyd has high dissolved oxygen and low ammonia levels today.
Areas further downstream were low in oxygen and high in ammonia.
Laboratory results will be available next week.
The DNR will continue to investigate to locate the source of the pollutant.
People can help protect water quality by immediately calling DNR at 515-725-8694 when they see dead fish or polluted water.