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Supplemental InformationSpecific conductance is given in microsiemens per centimeter at 25 degrees Celsius (µS/cm at 25 °C). Of the 54 pesticides that were analyzed for in the samples collected during July 2015, 47 pesticides were not detected in any samples. Seven pesticides-2-chloro-4-isopropylamino-6-amino-s-triazine (CIAT); 2,4-D; acetachlor; atrazine; glyphosate; metolachlor; and prometon-were detected in the 2015 samples with estimated concentrations or concentrations greater than the laboratory reporting level, and most pesticides were detected at low concentrations in only a few samples. Samples from all wetlands contained at least one detected pesticide. The maximum number of pesticides detected in a wetland sample was six, and the median number of pesticides detected was three.
Concentrations of chemical constituents inThe most commonly detected pesticides in the 2015 samples were atrazine and the atrazine degradate CIAT (also known as deethylatrazine), which were detected in 14 and 13 of the wetlands sampled, respectively. Glyphosate was detected in samples from 11 wetlands, and metolachlor was detected in samples from 10 wetlands. The other detected pesticides were 2,4-D (4 wetlands), acetochlor (3 wetlands), and prometon (1 wetland).The same pesticides that were detected in the 2006 samples were detected in the 2015 samples, with the exception of simazine, which was detected only in one sample in 2006. Atrazine and CIAT were the most commonly detected pesticides in both sampling years; however, atrazine and CIAT