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Watershed - Both
Atrazine Levels in Illinois Community Water System Drinking Water as Revealed by the Atrazine Monitoring Program Dataset
Atrazine is the most commonly applied pesticide in the United States with 76.5 million tons applied annually since 1990. Atrazine is widely found in the environment, and contaminates both ground water and surface water sources. Recent studies demonstrating possible adverse pregnancy outcomes, endocrine disruption potential, and carcinogenic activity at environmentally-relevant concentrations has increased concern about its occurrence in drinking water. The Atrazine Monitoring Program (AMP) was initiated by the USEPA Atrazine Re-registration Eligibility Decision of 2003. AMP monitors raw and finished water levels of Atrazine and Atrazine-degradates in community water services (CWS) at weekly intervals during the high- usage season, and biweekly during other times. USEPA’s risk assessment on exposure to Atrazine concluded that an average exposure of less than 37.5 ppb over a 90 day period is safe against the most sensitive health effect of changes in hormonal levels. In this paper we analyzed the entire Illinois AMP dataset (2003-2010) as part of a larger environmental public health tracking study investigating linkages between adverse pregnancy outcomes and agrochemicals in drinking water. We investigated the variability in occurrence of Atrazine in raw and finished water in 32 community water systems located in 21 counties across Illinois. Descriptive statistical analysis was performed for each year, with mean annual finished water Atrazine concentrations varying between 0.61-1.25 ppb. A peaking analysis (defined as the number of Atrazine concentration exceedances > mean+1σ) was performed for every biweekly period for all data years. Pronounced seasonal trends were observed in all monitoring sites with the majority of the peaks occurring in a time window of mid-August to mid-September. Atrazine removal efficiencies during CWS operation were determined for each treatment plant where data were available for raw and finished data pairs, and showed significant removal of Atrazine during CWS operations. Bi-weekly mean concentrations were compared to MCLs, MCLGs, Illinois groundwater action levels, and the USEPA’s intermediate-term exposure levels to determine the possible risk from exposure. Results demonstrate that the finished water Atrazine MCL (3 ppb) was exceeded 20-50 times per year, but only one Atrazine exceedance of the intermediate term exposure level was observed (in 2004).
Moderator: Dennis Ross
Karl Rockne - University of Chicago