Can rice (Oryza Sativa) mitigate pesticides and nutrients in agricultural runoff

Authors: Moore, Matthew; Locke, Martin

Submitted to: Bulletin of Environmental Contamination and Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/23/2017
Publication Date: 1/22/2018
Publication URL: http://handle.nal.usda.gov/10113/5888034
Citation: Moore, M.T., Locke, M.A. 2018. Can rice (Oryza Sativa) mitigate pesticides and nutrients in agricultural runoff. Bulletin of Environmental Contamination and Toxicology. 100(1):162-166. https://doi.org/10.1007/s00128-017-2225-0.
DOI: https://doi.org/10.1007/s00128-017-2225-0

Interpretive Summary: Pesticides and nutrients in agricultural runoff can harm downstream aquatic receiving systems such as rivers or lakes. Innovative management practices are needed at the field- and edge-of-field levels to reduce the potential impact of these chemicals to water bodies. Small scale experiments demonstrated that contaminated water flowing through systems housing rice plants resulted in significant reductions of various chemical loads. With the exception of nitrogen concentrations, systems without vegetation failed to produce similar reductions. Using rice for phytoremediation has the potential to address water quality concerns in developing countries that depend on the crop for their food supply. However, more research must be conducted on potential contaminant transfer to seed before moving toward large scale implementation.

Technical Abstract: Phytoremediation of nutrients and pesticides in runoff is a growing conservation effort, particularly in agriculturally intensive areas such as the lower Mississippi River Valley. In the current study, rice (Oryza sativa) was examined for its mitigation capacity of nitrogen, phosphorus, diazinon, and permethrin. Twenty-two high density polyethylene circular containers (56 cm x 45 cm) were used as mesocosms, with 12 mesocosms planted with rice and 10 mesocosms remaining unvegetated. Mesocosms were arranged in a series of two, with each system providing a 4 h hydraulic retention time (HRT) for a total system retention time of 8 h. Two treatments (RICE/RICE and RICE/BARE) of four replicates each were utilized, with three replicates of controls (BARE/BARE). Systems with RICE/RICE (8 h HRT) significantly reduced diazinon (p=0.0126), cis-permethrin (p=0.0442), filtered orthophosphate (p=0.0058), and total orthophosphate (p=0.0123) compared to control systems. Results indicate promise in phytoremediation of agricultural runoff by rice. If further studies reveal contaminants are not transferred into seeds, then rice could potentially serve as both a remediation tool and food source in developing countries facing agricultural pollution challenges.