Wednesday, November 15, 2006 - 10:00 AM

Waste Foundry Sand Soil Amendment to Reduce Atrazine Loading to Surface Runoff.

Elizabeth Warnemuende1, Brad Lee2, Robert Dungan3, and Jason De Koff2. (1) USDA-ARS, 275 S Russell St, West Lafayette, IN 47907-2077, (2) Purdue Univ, Agronomy Dept, 915 W State St, West Lafayette, IN 47907, (3) USDA-ARS-EMBUL, Beltsville, MD 20705

A series of experiments was conducted to evaluate the potential for surface applied foundry sand (FS) waste material to reduce atrazine in runoff water from fields having atrazine-based weed management. In the first experiment, the ability of several FSs to remove atrazine from the water column was evaluated. One-hundred mL of water having atrazine levels of 10 μg/L and 100 μg/L was exposed to 10 g of unamended soil (Blount silt loam), 50% soil / 50% FS, and 100% FS by shaking for 24 hours, and analyzed for atrazine by GC-MS. Results indicated that a calcium bentonite-coated waste foundry sand (Ca-FS) reduced atrazine in the water column by 68% as compared to soil. Atrazine levels in water were reduced by 60% using 50% Ca-FS. A laboratory rainfall simulation was then conducted on unamended soil and soil having surface-applied Ca-FS at 2000 kg/ha and 6000 kg/ha. Rainfall was applied at 50 mm/hr for 50 minutes, and then 75 mm/hr, 25 mm/hr, and 100 mm/hr for 15 minutes each to 0.2 m x 1 m soil boxes. Runoff was collected and analyzed for atrazine by GC-MS. Results indicated that atrazine levels in runoff from soil amended with Ca-FS were 30-37% lower than from unamended soil, regardless of application rate or rainfall rate. A similar field rainfall simulation was performed on 1 m x 2 m atrazine-treated corn plots having unamended soil, and soil with Ca-FS surface applied at 4000 kg/ha, under two different tillage systems. Results of this study will be presented.