Little Sioux River IA 06-LSR-1567

Assessment Comments

Assessment is based on results of U.S. EPA / IDNR fish tissue (RAFT) monitoring near Washta (Cherokee Co.) in 2004 and 2006.

Basis for Assessment

[Note:  Prior to the current (2008) Section 305(b) cycle, this river segment was designated only for Class B(WW1) aquatic life uses, including fish consumption uses.   Due to changes in Iowa’s surface water classification that were approved by U.S.  EPA in February 2008 (see http://www.iowadnr.com/water/standards/files/06mar_swc.pdf) and the results of an Use Attainability Analysis, this segment is also now designated for Class A1 (primary contact recreation) uses.   This segment remains designated for warmwater aquatic life use (now termed Class B(WW1) uses), and for fish consumption uses (now termed Class HH (human health/fish consumption uses).]

SUMMARY:  The Class A1 (primary contact recreation) uses and the Class B(WW1) aquatic life uses remain "not assessed" due to the lack of water quality information upon which to base an assessment.   The fish consumption uses remain assessed (monitored) as "fully supported" based on results of U.S.  EPA / IDNR fish tissue (RAFT) monitoring near Washta (Cherokee Co.) in 2004 and 2006.   This assessment is the same as that used for the adjacent downstream segment (IA 06-LSR-0020-2).

EXPLANATION:  The Class A1 (primary contact recreation) uses and the Class B(WW1) aquatic life uses remain "not assessed" due to the lack of sufficient water quality information upon which to base an assessment for this river reach.  

Fish consumption uses are assessed as "fully supported" based on the 2004 and 2006 EPA/IDNR fish tissue (RAFT) sampling on the Little Sioux River south of Washta (U.S.  EPA STORET station 008713).   This site has been sampled for whole-fish common carp since 1994 on an every-other-year basis as part of RAFT trend monitoring.   The results from the 2004 and 2006 samplings show low levels of the primary contaminants (chlordane, PCBs and mercury) in the composite whole-fish samples of common carp:  2004 sample:  mercury: 0.059 ppm; total PCBs: 0.09 ppm; and technical chlordane:  <0.03 ppm; 2006 sample:  mercury: 0.102 ppm; total PCBs: 0.09 ppm; and technical chlordane:  <0.03 ppm.   The existence of, or potential for, a fish consumption advisory is the basis for Section 305(b) assessments of support of fish consumption uses in Iowa’s rivers and lakes.   Prior to 2006, IDNR used action levels published by the U.S Food and Drug Administration to determine whether consumption advisories should be issued for fish caught as part of recreational fishing in Iowa.   In an effort to make Iowa’s consumption more compatible with the various protocols used by adjacent states, the Iowa Department of Public Health, in cooperation with Iowa DNR, developed a risk-based advisory protocol.   This protocol went into effect in January 2006 (see http://www.iowadnr.gov/fish/news/consump.html for more information on Iowa’s revised fish consumption advisory protocol).   Because the revised (2006) protocol is more restrictive than the previous protocol based on FDA action levels; fish contaminant data that previously suggested “full support” may now suggest either a threat to, or impairment of, fish consumption uses.   This scenario, however, does not apply to the fish contaminant data generated from the 2004 and 2006 RAFT samplings (or from previous RAFT trend monitoring) conducted in this assessment segment:  the levels of contaminants do not exceed any of the new (2006) advisory trigger levels, thus suggesting no justification for issuance of a consumption advisory for this waterbody.