Pleasant Creek Lake IA 02-CED-459

Assessment Comments

Assessment is based on results of (1) IDNR beach monitoring program, (2) surveys of DNR Fisheries Bureau, and (3) fish tissue monitoring.

Basis for Assessment

SUMMARY:  The Class A (primary contact recreation) uses were assessed as "fully supporting."  The Class B(LW) aquatic life uses remained assessed as fully supporting"; fish consumption uses were assessed as "fully supported."  EXPLANATION:  Levels of indicator bacteria at Pleasant Creek Lake beach were monitored approximately twice per week during summer 1999 by DNR Parks, Recreation and Preserves Division as part of a beach monitoring program at 11 state-owned lakes.   Results of the 35 samples collected at this beach showed that levels of indicator bacteria (fecal coliforms) were generally low, with the overall geometric mean (14 orgs/100 ml) well below the state water quality criterion of 200 orgs/100 ml.   The maximum level of fecal coliforms in the 34 samples was 190 orgs/100 ml on August 23, 1999.   Thus, no samples exceeded the state water quality criterion of 200 orgs/100 ml.   According to U.S.  EPA guidelines for determining "full support" of primary contact uses (U.S.  EPA 1997b, page 3-35), the geometric mean of fecal coliform bacteria levels should not exceed 200 orgs/100ml based on at least five samples in a 30-day period.   In addition, not more than 10% of the total samples taken during any 30-day period should have a density that exceeds 400 orgs/100 ml.   None of the sixteen 30-day periods during summer 1999 had geometric means (N = from 6 to 10 samples per period) greater than the state water quality criterion of 200 orgs/100ml.; the maximum 30-day geometric mean was 22 orgs/100ml.   No samples exceeded the EPA-recommended single sample maximum density for fecal coliform bacteria of 400 orgs/100ml.   Thus, the Class A (primary contact recreation) uses were assessed as "fully supported."  The Class B(LW) aquatic life uses remain assessed as "fully supporting" based on review and approval of the previous (1998) assessments by the DNR Fisheries Bureau in 2000.   Fish consumption were assessed as "fully supported" based on results of EPA/DNR fish tissue (RAFT) monitoring in August 1999 that showed very low levels of all contaminants in the composite samples of fillets from channel catfish and largemouth bass; all contaminant levels were less than  ½ of respective FDA action levels and DNR levels of concern.