Sand Lake B IA 02-IOW-1987

Assessment Comments

Assessment is based on based on U.S. EPA/Iowa DNR fish contaminant (RAFT) monitoring in 2004.

Basis for Assessment

SUMMARY/EXPLANATION:  The Class B(LW) aquatic life uses of Sand Lake remain “not assessed” due to lake of water quality information upon which to base an assessment.   The fish consumption uses are assessed (evaluated) as “fully supported” based on U.S.  EPA/Iowa DNR fish contaminant (RAFT) monitoring in 2004.  

The fish consumption uses of Sand Lake are assessed (evaluated) as "fully supported" based on the 2004 EPA/IDNR fish tissue (RAFT) sampling.   The composite samples of fillets from largemouth bass and common carp fillets from this lake had low levels of the primary contaminants (mercury, total PCBs, and technical chlordane); all of these contaminants were below levels of concern.   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.   The results from the 2004 sampling showed low levels of chlordane, PCBs, and mercury in both composite samples.   Levels of contaminants in the composite sample of largemouth bass fillets were as follows:  mercury:  0.122 ppm; total PCBs:  <0.09 ppm; and technical chlordane:  <0.03 ppm.   Levels of contaminants in the sample of common carp fillets were as follows:  mercury:  0.078 ppm; total PCBs:  <0.09 ppm; and technical chlordane:  <0.03 ppm.   Because these data are now considered too old (greater than five years) to accurately characterize current water quality conditions, the assessment category is considered “evaluated” (indicating an assessment with relatively lower confidence) as opposed to "monitored" (indicating an assessment with relatively higher confidence).    The existence of, or potential for, a fish consumption advisory is the basis for Section 305(b) assessments of the degree to which Iowa’s lakes and rivers support their fish consumption uses.    The fish contaminant data generated from the 2004 RAFT sampling conducted in this lake show that the levels of contaminants do not exceed any of the advisory trigger levels, thus suggesting no justification for issuance of a consumption advisory for this waterbody.