|Abdul Baki, Aref|
Submitted to: Environmental Toxicology and Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/21/2007
Publication Date: 11/1/2007
Citation: Rice, P.J., Hapeman, C.J., Mcconnell, L.L., Sadeghi, A.M., Teasdale, J.R., Coffman, C.B., Mccarty, G.W., Abdul Baki, A.A., Starr, J.L. 2007. Evaluation of vegetable production management practices to reduce the ecological risk of pesticides. Environmental Toxicology and Chemistry. 26(11):2455-2464. Interpretive Summary: Pesticides are utilized widely in both agricultural and non-agricultural settings to assure an abundant supply of food and fiber and to control harmful pests. The detection of pesticides at locations where they had not been applied and their reported negative impacts to non-target organisms has resulted in public concern. This manuscript evaluates relative risk reductions associated with agricultural pesticide use for different management practices of vegetable production. Measuring pesticide loads in edge-of-field runoff and extrapolation and assessment of relative risk to aquatic organisms in receiving waters demonstrated that changes in mulching practices will reduce concentrations of pesticides in tributaries to levels below median lethal concentrations and below U.S. EPA guidelines to protect aquatic life. This research will benefit both agricultural producers and the environment as understanding processes that control the environmental fate of pesticides, their exposure and risk to non-target species, and identifying management practices that reduce the off-site transport of pesticides will increase pesticide efficacy at sites of application while reducing pesticide concentrations in surrounding surface waters; thereby minimizing exposure and adverse impacts to non-target aquatic organisms.
Technical Abstract: The ability of agricultural management practices to reduce the ecological risks of pesticides was evaluated. Risk quotients, a mathematical description of the relationship between exposure and toxicity, and hazard ratings, a rank of potential risk of pesticides to aquatic environments, were calculated for conventional and two alternative cultivation practices for tomatoes: POLY-Bare, raised beds covered with polyethylene mulch with bare-soil furrows; POLY-Rye, raised beds covered with polyethylene mulch with cereal-rye (Secale cereale) grown in the furrows; and VETCH, raised beds and furrows planted with hairy vetch seed (Vicia villosa). Evaluations were conducted using measured pesticide concentrations in runoff at the edge-of-field and estimated environmental concentrations in an adjacent creek and a theoretical pond receiving the runoff. Runoff from POLY-Bare presented the greatest hazard to ecosystem health and to sensitive organisms, whereas the use of VETCH minimizes these risks. Previous studies have shown that harvest yields were maintained and runoff volume, soil loss, and off-site transport of pesticides measured in runoff were reduced when using the alternative management practices (POLY-Rye and VETCH). Together, these results indicate that the alternative management practices (POLY-Rye and VETCH) have a less adverse impact on the environment than the conventional management practice (Poly-Bare) while providing growers with an acceptable economic return. In addition, this study demonstrates the need to consider the management practice when assessing the potential risks and hazards for certain pesticides.