Prior studies, including the previous pesticide monitoring program, have indicated that agricultural activities often produce elevated nitrate nitrogen concentrations in groundwater. The average nitrate concentration found in the 7 golf course irrigation wells sampled in 2001 was 4.7 mg/L, with a median concentration of 3.5 mg/L. No wells exceeded the nitrate MCL of 10.0 mg/L. The irrigation well at Engineers Country Club had the highest nitrate concentration of 8.0 mg/L (This well also exhibited a metalaxyl concentration of 0.15 ug/L).
Nitrite was not detected in any of the samples and there was 1 ammonia detection of 0.26 mg/L at the Garden City Country Club irrigation well. Table 4 summarizes the Ammonia, Nitrite and Nitrate concentrations for each golf course well sampled in 2001.