Master of Science (MS)
Triazine herbicides are the most heavily used pesticides in the United States. Atrazine and Simazine are the primary triazine herbicides used for broadleaf weed control in the production of corn, sugarcane, and sorghum. Recent monitoring studies of surface waters in the Upper Terrebonne Basin of Louisiana indicate elevated amounts of triazines are running off fields and entering drinking water supplies. Atrazine has been classified as a possible carcinogen by the United States Environmental Protection Agency. Recent epidemiological studies have revealed increases in breast cancer and pre-term births following exposure to triazines at levels detected in drinking water. Non-point source pollution is a major problem affecting the water quality in the United States. Agriculture contributes a large percentage of non-point source water pollution, with sediment, pesticides and animal waste transported into waterways with surface runoff. Recent amendments to the Clean Water Act require that States identify impaired waters and develop Total Maximum Daily Load Budgets for these waters. Best Management Practices have been advocated as a method to reduce non-point pollution to meet these new regulations. Data were collected in the Upper Terrebonne Basin of Louisiana before and after the farmers were advised to follow Best Management Practices to reduce Atrazine runoff . Samples of finished and raw water were collected from Iberville Water District Three and analyzed for atrazine concentration by the Louisiana Department of Agriculture and Forestry. Atrazine concentration data were evaluated using Dynamic Linear Models, with stream flow from Bayou Grosse Tete as a regressor. This analysis revealed that stream flow has a significant influence and accounts for most of the change in atrazine concentrations at the Iberville water facility. The trend in acreage of crops planted in the UTB had a decrease in the number of crop acres that could utilize Atrazine. The sale of Atrazine in the UTB also increased for the years at the beginning and end of this study. From the results of the time series analysis, it appears that Best Management Practices had less effect than stream flow on Atrazine concentrations at Iberville Water District Three.
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Walther, John S., "Surface water pesticide contamination in the Upper Terrebonne Basin of Louisiana" (2003). LSU Master's Theses. 975.
E. Conrad Lamon III