Desoto Bend IA 06-WEM-1716

Assessment Comments

Assessment is based on results of (1) surveys by IDNR Fisheries Bureau, (2) ISU report on lake plankton communities, and (3) results of U.S. EPA/IDNR fish tissue monitoring in 1998.

Basis for Assessment

SUMMARY:  The Class A (primary contact recreation uses) were "not assessed."  Continued to assess support of the Class B(LW) aquatic life uses as "fully supported / threatened."  Fish consumption uses were assessed as "fully supported."  EXPLANATION:  The level of support of the Class A (primary contact recreation) uses was changed from "fully supported / threatened" to "not assessed" due to the lack of information on levels of indicator bacteria at this lake.   This change in assessment reflects a change in the DNR's Section 305(b) assessment methodology and does not reflect any known change in water quality.   The previous (1998) assessment of support of the Class B(LW) uses ("fully supported / threatened") was reviewed and approved by the DNR Fisheries Bureau in 2000.   Fish consumption were assessed as "fully supported."  EPA/DNR fish tissue (RAFT) monitoring conducted in 1998 showed that levels of contaminants in the composite sample of fillets from common carp and largemouth bass were less than ½ of the respective FDA action levels and DNR levels of concern for organochlorine contaminants and mercury.   Thus, fish consumption uses were assessed as "fully supported."