Assessment Comments

Assessment is based on results of U.S. EPA/IDNR fish tissue (RAFT) monitoring in 2000 and 2002.

Basis for Assessment

SUMMARY:  The Class A (primary contact recreation) uses and Class B(WW) aquatic life uses are "not assessed" due to the lack of water quality information upon which to base an assessment.   Fish consumption uses are assessed (monitored) as "fully supported" based on fish contaminant monitoring.   The source of data for this assessment is the results of U.S.  EPA/IDNR fish contaminant monitoring in 1998, 2000, and 2002 at Keosauqua.  

EXPLANATION:  The Class A uses and Class B(WW) uses were not assessed due to the lack of water quality monitoring and other water quality information for this river segment upon which to assess support of these uses.   Prior to the 2002 report, these uses were assessed based on results of water quality monitoring conducted near Keokuk (see assessments for the 1998 and 2000 reports).   This monitoring station, however, is more than 30 miles downriver from the current assessment segment (IA 04-LDM-0010-3), and previous assessment likely represent an excessive extrapolation of the monitoring results from the Keokuk station.   Results of EPA/DNR fish tissue (RAFT) trend monitoring near Keosauqua in 1998, 2000, and 2002 showed that  the composite sample of whole-fish common carp collected from this site have low levels of contaminants.   The sample collected in 2002 did not contain levels of contaminants that approached even one-half the respective FDA action levels or IDNR levels of concern.   Levels of primary contaminants in the sample were as follows: mercury: 0.101 ppm; total PCBs: 0.135 ppm; and technical chlordane: 0.120 ppm.