Little Sioux River IA 06-LSR-1573

Assessment Comments

Assessment is based on results of IDNR/UHL ambient city monitoring from 2002-04.

Basis for Assessment

SUMMARY:  The Class B(WW) aquatic life uses are assessed (monitored) as "fully supported” based on results of ambient water quality monitoring from 2002 through 2004.   Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this river segment.   The source of data for this assessment is the results of monthly chemical/physical monitoring from 2002 through 2004 at the IDNR/UHL ambient city monitoring station located downstream from Spencer at the County Road M50 bridge east of Spencer (STORET station 10210003).  

EXPLANATION:  Monitoring at the IDNR/UHL city station downstream from Spencer showed no violations of Class B(WW) water quality criteria for pH, dissolved oxygen (minimum value = 5.8 mg/l) or ammonia nitrogen (maximum value = 0.52 mg/l) in the 36 samples analyzed during the 2002-2004 period.   In addition, levels of pesticides in the seven samples analyzed, and levels of toxic metals in the 32 samples analyzed, were all below their respective Class B(WW) criteria.   Although one of 28 samples exceeded the Class B(WW) chronic criterion for copper during the previous (2004) assessment cycle, none of the 32 samples analyzed for copper during the current (2006) assessment cycle exceeded the Class B(WW) criterion.   These results suggest "full support" of the Class B(WW) aquatic life uses.    

Fish consumption uses remain "not assessed" due to the lack of recent fish contaminant monitoring data for this river segment.