In August 2018 the mayor of Evansville sent a letter to the Ohio River Valley Water Sanitation Commission (ORVWSO) opposing a proposal to eliminate pollution control standards for the Ohio River. Evansville is located downstream from the river's origin. Sources of pollution that affect water quality include agricultural runoff, raw sewage discharges from combined sewer overflows, and toxic chemicals released by companies with water pollution permits. The State of Indiana issues a fish consumption advisory for fish from the Ohio River based on PCB contamination. The recommended consumption limit for most fish, including carp, striped bass and flathead catfish is no more than 8 oz. per month, but for channel catfish, the recommendation is only 8oz every two months.