Environmental officials are monitoring a northwest Iowa stream after cattle manure flowed into it last week.
The Des Moines Register reports the manure flowed into a tributary of the Rock River near Inwood after it was improperly applied to a corn field.
The Iowa Department of Natural Resources is investigating the situation.
The manure came from a 4,000-head cattle facility. After it was applied to the field, the manure flowed into a creek and a neighbor's pond.
The high levels of ammonia from manure can kill fish and other aquatic life.
Officials did not find any dead fish in the creek on Thursday and Friday, but they plan to continue monitoring it.