The Acetochlor Registration Partnership Surface Water Monitoring Program for Four Corn Herbicides

Abstract

A surface drinking water monitoring program for four corn (Zea mays L.) herbicides was conducted during 1995-2001. Stratified random sampling was used to select 175 community water systems (CWSs) within a 12-state area, with an emphasis on the most vulnerable sites, based on corn intensity and watershed size. Finished drinking water was monitored at all sites, and raw water was monitored at many sites using activated carbon, which was shown capable of removing herbicides and their degradates from drinking water. Samples were collected biweekly from mid-March through the end of August, and twice during the off-season. The analytical method had a detection limit of 0.05 microg L(-1) for alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)-acetamide] and 0.03 microg L(-1) for acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-acetamide], atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine], and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)-acetamide]. Of the 16528 drinking water samples analyzed, acetochlor, alachlor, atrazine, and metolachlor were detected in 19, 7, 87, and 53% of the samples, respectively. During 1999-2001, samples were also analyzed for the presence of six major degradates of the chloroacetanilide herbicides, which were detected more frequently than their parent compounds, despite having higher detection limits of 0.1 to 0.2 microg L(-1). Overall detection frequencies were correlated with product use and environmental fate characteristics. Reservoirs were particularly vulnerable to atrazine, which exceeded its 3 microg L(-1) maximum contaminant level at 25 such sites during 1995-1999. Acetochlor annualized mean concentrations (AMCs) did not exceed its mitigation trigger (2 microg L(-1)) at any site, and comparisons of observed levels with standard measures of human and ecological hazards indicate that it poses no significant risk to human health or the environment.

Drinking-Water Herbicide Exposure in Indiana and Prevalence of Small-for-Gestational-Age and Preterm Delivery

“…We had access to three additional data sets of atrazine concentrations in finished drinking water in Indiana, each of which contained records from biweekly sampling for periods of several months to several years. These data were collected as part of the Acetochlor Registration Partnership (Hackett et al 2005), Novartis Atrazine Public Water System Voluntary Monitoring (Tierney et al 1999), and the Atrazine and Simazine Re-registration Program (U.S. EPA 2006).…”

The Metolachlor Herbicide: An Exercise in Today's Stereochemistry

“…It is reported that herbicides sometimes appear in surface or ground water (2,37,39); corresponding risk assessments of (S)-metolachlor resulted in positive registrations in the United States (in 1997) and other countries. This agent and several materials containing (S)-metolachlor and some additives have been marketed by the Syngenta company under the trade names Dual Gold, Dual Magnum, Gardo Gold, Primextra Gold, and others.…”

Seed Germination and Morphological Behavior of Maize (NAC-6002, NAC-6004 and NAH- 2049) Seedlings under Abiotic Stress (Alachlor) Condition

“…In India this herbicide is available as Lasso, used both as pre and post emergent herbicide. The herbicide is available as emulsifiable concentration (Garrett et al, 1986;Kiely et al, 2004 andHackett et al, 2005). The herbicide alachlor absorbed by emerging plant shoots, inhibits fatty acid and lipid biosynthesis; as well as gibberellins synthesis and protein synthesis (Chang et al, 1985).…”