Pesticides in Streams of the United States--Initial Results from the National Water-Quality Assessment Program

By Steven J. Larson, Robert J. Gilliom, and Paul D. Capel

U.S. GEOLOGICAL SURVEY
Water-Resources Investigations Report 98-4222
Sacramento, California, 1999

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Figure 18. Distribution of median total pesticide concentrations for each month for each of the three types of sites. Each boxplot represents the distribution of monthly median concentrations for 1 month among the sites in each group for a 1-year period. Five agricultural indicator sites (acfb-aycocks, gafl-little, redn-wildr, wmic-duck, wmic-nbmilw) had insufficient sampling during some months and therefore were not included in plot A. Three urban indicator sites (lsus-cedar, trin-rush, whit-little), which had substantial amounts of agricultural land in the drainage basin, were not included in plot B. (See figure 5A and associated text for an explanation of boxplots.)

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