Iowa River IA 02-IOW-622

Assessment Comments

Assessment is based on results of (1) USGS/NAWQA monitoring at Wapello from 1993-1995 and (2) fish tissue (RAFT) monitoring in 1995.

Basis for Assessment

Used results from the 1995 RAFT (fish tissue) sampling to continue to assess fish consumption uses as FS.*  The USGS NASQAN station at Wapello was discontinued after September 1995; continue to use these data for assessing support of the Class B(WW) aquatic life and Class A primary contact uses.   Assess overall support as FST due to known threats from nonpoint source pollution.   Results of USGS fish tissue monitoring for the National Water Quality Assessment (NAWQA) program in September 1995 near Wapello show that levels of organochlorine contaminants (chlordane, dieldrin, DDT, and PCBs) in a composite sample of whole-fish carp were less than 1/2 the respective FDA action levels.   These results are consistent with results of the 1995 RAFT sampling and support the assessment of FS for fish consumption uses.   For more info on the USGS fish tissue study, see USGS Fact Sheet FS-027-97.  *Results from the 1997 RAFT fish contaminant monitoring program were received in August 1998.   These results show that the level of technical chlordane (0.21 ppm) in the composite sample of whole-fish carp collected near Wapello exceeded 1/2 of the FDA action level for chlordane (0.30 ppm).   Fish consumption uses FST.