Iowa River IA 02-IOW-627

Assessment Comments

Assessment is based on results of fish tissue (RAFT) monitoring.

Basis for Assessment

Used results of RAFT fish tissue monitoring conducted in 1994 and 1995 that showed levels of chlordane in bottom feeder fillets less than the FDA action level but greater than 1/2 this action level (=FST).   RAFT monitoring conducted in 1997 at Iowa City & Hills continued to show similar results:  the level of technical chlordane in compsite samples of fillets of channel catfish and carp were less than the FDA action level of 0.300 ppm, but the level of chlordane in the sample of channel catfish fillets from Iowa City was greater than 1/2 of this action level (0.17 ppm).   Thus, continue to assess support of the fish consumption uses as FST.   RAFT monitoring will continue on an every-other-year basis to track levels of chlordane.   Similar to previous years, assessments of support of the Class A (primary contact recreation) and Class B(WW) (aquatic life) uses were not developed for this waterbody segment, despite a long-term monitoring station just upstream from the Burlington Street dam, due to presence of potential significant influences on water quality (e.g., Iowa City wastewater treatment plants) in this segment.