IMPROVED WATER RESOURCES MANAGEMENT FOR IRRIGATED AGRICULTURE IN THE PACIFIC NORTHWEST
Location: Northwest Irrigation and Soils Research
Title: Acrylamide monomer leaching from polyacrylamide-treated irrigation furrows
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 10, 2008
Publication Date: November 18, 2008
Citation: Lentz, R.D., Andrawes, F.F., Barvenik, F.W., Koehn, A.C. 2008. Acrylamide monomer leaching from polyacrylamide-treated irrigation furrows. Journal of Environmental Quality. 37:2293-2298.
Interpretive Summary: In a well accepted and employed soil conservation practice, water-soluble polyacrylamide (WSPAM) is added to water in small amounts to dramatically reduce erosion in furrow irrigated fields. The WSPAM product contains less than 0.05% of a chemical, acrylamide monomer, which is toxic to humans and animals, a suspected carcinogen, and is readily dissolved and transported in flowing water. Though it is biodegradable, there is some concern that acrylamide monomer may leach into groundwater beneath WSPAM-treated fields. This study showed that acrylamide monomer concentration in percolation water samples was within a range the U.S. Environmental Protection Agency considers safe for potable water supplies. The risk that groundwater beneath these PAM-treated, furrow irrigated soils will be contaminated with AMD appears minimal. This information is important because it indicates that this effective soil and water conserving practice is safe for use in these silt loam soils.
Water-soluble polyacrylamide (WSPAM), used to reduce erosion in furrow irrigated fields and other agriculture applications, contain less than 0.05% Acrylamide monomer (AMD). The AMD, a potent neurotoxicant and suspected carcinogen, is readily dissolved and transported in flowing water. Deep percolation beneath furrow-irrigated fields ranges from 7 to 325 mm per crop season, thus, AMD may leach into the vadose zone beneath WSPAM-treated fields. We measured the AMD in water leached below the crop root zone in a furrow-irrigated silt loam soil. Continuous extraction methods using buried, walled percolation samplers were used to monitor soil water flux and collect leachate water. The samplers were placed at 1.2 m depths at 30-m and 150-m intervals across a 180-m-long corn field. The field was furrow irrigated using WSPAM at the rate of10 mg/L during furrow advance. Percolation water and furrow inflows were monitored for AMD during and after three furrow irrigations. The samples were analyzed for AMD using gas chromatograph equipped with an electron-capture detector. Furrow inflows contained an average AMD concentration of 5.5 ug/L. The AMD in percolation water samples never exceeded the minimum detection limit and de facto potable water standard of 0.5 ug/L. The risk that groundwater beneath these PAM-treated furrow irrigated soils will be contaminated with AMD appears minimal.