(564c) Field Sampling of Atrazine-Contaminated Water/Sediment in the Rio Grande Basin

Atrazine (C8H14ClN5) is the most extensively used Herbicide (Weed Killer for corn, sugarcane and other crops) with an annual usage > 60 million pounds and much makes its way into streams, rivers, lakes and drinking water supplies. This study involved field sampling of atrazine-contaminated water/sediment and indentifying the extent, seasonal trend, polluted sites, and potential risks of atrazine-contamination in the Rio Grande Basin. Atrazine adsorbed in sediment is determined by hot solvent extraction followed by HPLC (Agilent 1100 HPLC with a Zerobax Eclipse C-8 Column and a variable wavelength detector at 222 nm). Field Sampling efforts included 9 expeditions and 114 sites visited in CO, NM, and TX. The project provides a valuable profile on the extent of atrazine pollution in term of time and location and identifies the environmental risks of polluted water and sediment along the Rio Grande Basin due to pesticide uses. Atrazine in water appears to be below the EPA intermediate-term level of concern (37.5 ppb over a 90-day period). However, atrazine entrained in sediment sometimes exceeds this level. Further sampling and analysis are thus warranted to ensure the water quality in the Rio-Grande Basin.