Mississippi River IA 01-NEM-71

Assessment Comments

Assessment is based on (1) LTRMP ambient monitoring from 2002-04, (2) interstate consultation with Illinois EPA in 2012, and (3) result of U.S. EPA/IDNR fish contaminant trend monitoring 2008 2010 and 2012.

Basis for Assessment

SUMMARY:  The Class A1 (primary contact recreation) uses are considered “not assessed” due to the lack of monitoring information upon which to base an assessment.   The Class B(WW1) aquatic life uses remain assessed (monitored) as "fully supporting" based on results of LTRMP ambient chemical/physical water quality monitoring from 2002 through 2004.   Fish consumption uses are assessed (monitored) as "fully supported" based on the removal of the "one meal per week" fish consumption advisory for Pool 12 of the Mississippi River in 2011.   The sources of data used for this assessment are (1) results of routine chemical/physical water quality monitoring conducted at station M582.5B at the Lock and Dam 11 tailwater from January 2002 through September 2004 by IDNR staff of the Upper Mississippi River Long-Term Resource Monitoring Program (LTRMP) at Bellevue, IA, (2) interstate consultation with Illinois EPA through the UMRBA Water Quality Task Force, (3) result of U.S.  EPA/IDNR fish contaminant trend monitoring 2008, 2010, and 2012.

EXPLANATION:  The Class A1 (primary contact recreation) uses remain “not assessed” due to the lack of information upon which to base an assessment.   Water quality monitoring conducted by LTRMP does not include analysis for indicator bacteria.  

The Class B(WW1) (aquatic life) uses remain assessed (evaluated) as “fully supported” based on results of water quality monitoring from LTRMP station M582.5B at the tailwater area of Lock and Dam 11.   Results of monitoring from 2002-04 at this station show no violations of Class B(WW1) water quality criteria for dissolved oxygen, pH, or ammonia-nitrogen in the 17 samples collected.   Note:  LTMRP monitoring has not been conducted at this station since 2004.  

Fish consumption uses are assessed (monitored) as "fully supported" based on the removal of the "one meal per week" fish consumption advisory for this Pool 12 of the Mississippi River in 2011 and based on results of fish contaminant monitoring in 2012 (see the previous (2012) assessment for this segment for details of issuance and removal of the fish consumption advisory for this assessment segment).   This segment 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, 2006, and 2008 trend sampling all show low levels of the primary contaminants (chlordane, PCBs and mercury).    The results for the 2008 sample are as follows:  mercury: 0.104 ppm; total PCBs: 0.159 ppm; and technical chlordane: <0.03 ppm.   The results for the 2010 sample are as follows:  mercury: 0.111 ppm; total PCBs: 0.277 ppm; and technical chlordane: 0.031 ppm.   The results for the 2012 sample are as follows:  mercury: 0.069 ppm; total PCBs: 0.142 ppm; and technical chlordane:  <0.03 ppm.   These results do not suggest the need to issue a consumption advisory for this waterbody for PCBs.   Thus, the fish consumption uses are assessed (monitored) as “fully supported”.   Thus, results of RAFT monitoring in this river segment do not suggest the need to issue a consumption advisory for this waterbody for PCBs.