What are Some Examples of WARP Predictions?
Figure 4 shows predicted annual mean concentrations for 2007. Model predictions of atrazine levels in streams across the Nation show the highest annual mean concentrations throughout the high-use areas of the Corn Belt and the Mississippi Valley and Delta regions, and in some areas of Texas, Pennsylvania, and Maryland. Annual means for a few streams in Missouri, Kansas, and Texas are predicted to exceed 3 ug/L, the human-health benchmark for atrazine. This benchmark is the USEPA MCL for drinking water. As a drinking-water standard, the MCL applies to finished drinking water in public water supplies, whereas the predictions are for untreated stream water. Comparisons of model predictions with human-health benchmarks, however, serve as a screening-level assessment of the suitability of potential drinking-water sources. Figure 4. WARP estimates of annual mean concentrations of atrazine in U.S. streams (nonagricultural sources are not accounted for). Figure 5 shows the probability that str
