acetochlor registration partnership: prospective ground water monitoring program. [Erratum: 2005 July-Aug., v. 34, no. 4, p. 1454.]

• Published in: Journal of environmental quality Vol. 34; no. 3; pp. 1004 - 1015
• Main Authors: Newcombe, A.C, Gustafson, D.I, Fuhrman, J.D, Van Wesenbeeck, I.J, Simmons, N.D, Klein, A.J, Travis, K.Z, Harradine, K.J
• Format: Journal Article
• Language: English
• Published: Madison American Society of Agronomy, Crop Science Society of America, Soil Science Society 01.05.2005; Crop Science Society of America; American Society of Agronomy
• Subjects: acetochlor; Agronomy. Soil science and plant productions; Applied sciences; Biological and medical sciences; corn; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; environmental fate; Environmental Monitoring; environmental programs; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; governmental programs and projects; Groundwater; groundwater contamination; herbicide residues; Herbicides - analysis; human health; Humans; leaching; losses from soil; Nutrients; pesticide registration; Pollution; Pollution, environment geology; Porosity; Public Health; Risk Assessment; soil degradation; Soil Pollutants - analysis; Soil sciences; soil transport processes; Solubility; textural soil types; Toluidines - analysis; United States; Water Movements; Water Pollutants - analysis; water pollution; Zea mays; Indiana; Corn Belt region; Minnesota; Kansas; Delaware; Nebraska; Pennsylvania; Iowa; Illinois; Missouri; Ohio; Maryland; Wisconsin; United States; North America; America; USA; Irrigation; Monocotyledones; Zea mays; Growing season; Texture; Interstitial water; Transport process; Prospective; Rain; Health and environment; Surveillance; Gramineae; Angiospermae; Surface water; Lixiviation; Spermatophyta; Degradation product; Public health; Concentration distribution; Ground water
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2004.0428

The Acetochlor Registration Partnership conducted a prospective ground water (PGW) monitoring program to investigate acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-acetamide] transport to ground water at eight sites. The distribution of soil textures among these sites was weighted toward coarser soil types, while also including finer-textured soils that dominate most corn (Zea mays L.)-growing areas of the United States. Each site consisted of a 1.2-ha test plot adjacent to a 0.2-ha control plot. Suction lysimeters and monitoring wells were installed at multiple depths within each test and control plot to sample soil-pore water and near-surface ground water. Irrigation was applied to each site during the growing season to ensure water input of 110 to 200% of average historical rainfall. Acetochlor dissipated rapidly from surface soils at all sites with a DT58 (time for 50% of the initial residues to dissipate) of only 3 to 9 d, but leaching was not an important loss mechanism, with only 0.25% of the 15 312 soil-pore water and ground water samples analyzed containing parent acetochlor at or above 0.05 microgram L(-1). However, quantifiable residues of a soil degradation product, acetochlor ethanesulfonic acid, were more common, with approximately 16% of water samples containing concentrations at or above 1.0 microgram L(-1). A second soil degradation product, acetochlor oxanilic acid, was present at concentrations at or above 1.0 microgram L(-1) in only 0.15% of water samples analyzed. The acetochlor PGW program demonstrated that acetochlor lacks the potential to leach to ground water at detectable concentrations, and when applied in accordance with label restrictions, is unlikely to move to ground water at concentrations hazardous to human health.