Home Lake IA 05-GRA-1373

Assessment Comments

Assessment is based on results of Syngenta's Iowa Voluntary Atrazine Monitoring Program from 2000-02.

Basis for Assessment

SUMMARY:  The Class A (primary contact recreation) uses and the Class B(LW) aquatic life uses are "not assessed" due to the lack of water quality information upon which to base an assessment.   The Class C (drinking water) uses are assessed (monitored) as "not supported " due to average levels of atrazine above state water quality criteria and the U.S.  EPA MCL.   Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this lake.   The source of data for this assessment is the results of the Iowa Voluntary Atrazine Monitoring Program conducted in 2000, 2001, and 2002 by Syngenta Crop Protection, Inc.  (formerly Novartis Crop Protection, Inc.).  

EXPLANATION:  The Class A and Class B(WW) uses remain "not assessed" due to the lack of water quality information for this lake.  

The assessment of support of the Class C (drinking water) uses was based on the results of the Syngenta "Iowa Voluntary Atrazine Monitoring Program" in 2000, 2001, and 2002.   This monitoring showed that the time-weighted mean levels of atrazine in samples collected from Home Pond in calendar years 2000 and 2001 were below the MCL of 3 ug/l; the time-weighted mean in 2002, however, was above the MCL.   The time-weighted mean of atrazine in in 2000 (N=31) was 1.34 ug/l, in 2001 (N=29) was 2.94 ug/l, and in 2002 (N=14) was 4.4 ug/l.   These results suggest a steady increase in the levels of atrazine over the last three years.   Ten of the 46 moving annual averages calculated for the 2000-2002 period were above the MCL of 3 ug/l (range:  1.0 to 4.9 ug/l).   Based on DNR's Section 305(b) assessment methodology, if the average contaminant level in source water is greater than the MCL, the Class C (drinking water) uses of the source water should be assessed as "not supported."    

Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring at this lake.