TRENDS OF ATRAZINE AND METOLACHLOR CONCENTRATION IN STREAMS AT MULTIPLE SPATIAL SCALES
Atrazine and metolachlor are detected in U.S. waters at concentrations that may have adverse effects on aquatic organisms and human health. Stream samples were collected for quantification of pesticide and nutrient concentrations in Indiana. A meta-analysis of national data was conducted for comparison. Regionally, concentration of atrazine was positively related to metolachlor (95% CI = 0.06 to 0.40) and peak concentrations did not occur during high discharge. Sediment-bound metolachlor were positively related to sediment-bound atrazine (95% CI = 0.14 to 0.54) and total organic carbon (95% CI =0.20 to 0.76). Nationally, peak atrazine and metolachlor were detected in spring with highest mean concentrations of atrazine in the Midwest and metolachlor in California. Regionally, discharge was not the best predictor of observed pesticide concentrations due to drought conditions. Nationally, atrazine concentrations were positively related to metolachlor concentrations ((95% CI = 0.95 to 1.00) and ammonium (95% CI = <0.01 to 0.04). metolachlor concentration were positively related to nitrate (95% CI = 0.03 to 0.08), phosphate (95% CI = <0.01 to 0.04), and atrazine (95% CI = 0.66 to 0.70), but negatively to pH (95% CI = -0.04 to -0.01).
Melody Bernot (Co-Presenter/Co-Author), Ball State University, firstname.lastname@example.org;
DANIEL ELIAS (Primary Presenter/Author), North Carolina Wesleyan College, email@example.com;
Jason Doll (Co-Presenter/Co-Author), Michigan State University, firstname.lastname@example.org;