Iowa River IA 02-IOW-628

Assessment Comments

Assessment is based on results of routine water quality & fish tissue monitoring as part of the UI/ACOE Coralville Water Quality Study.

Basis for Assessment

No violations of either conventional or toxic Class B(WW) water quality criteria in the 45 samples collected between October 1995 and September 1995; thus, assess support of the Class B(WW) aquatic life uses as FST.   Continue to assess support of the fish consumption uses as FS due to ongoing ACOE fish contaminant monitoring that shows levels of chlordane, dieldrin, heptachlor epoxide, and DDE well below 1/2 of FDA action levels in samples of whole-fish carp collected from downstream of Coralville Reservoir in June 1996.   No violations of WQ criteria for Class C (drinking water) uses, including no violations of the nitrate criterion in the 44 samples analyzed between October 1995 and October 1997; thus, assess support of Class C uses as FS.   Assessed support of the Class A (primary contact recreation) uses as FS due to (1) geometric mean of fecal coliform bacteria in the 14 non-flow affected samples of 68 organisms/100 ml (i.e., less than the 200 orgs/100 ml WQ criterion) and (2) no samples exceeding 400 orgs/100 ml.