Submitted to: Bulletin of Environmental Contamination and Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/26/2009
Publication Date: 3/17/2009
Citation: Moore, M.T., Lizotte Jr, R.E., Kroger, R. 2009. Efficiency of experimental rice (Oryza sativa L.) fields in mitigating diazinon runoff toxicity to Hyalella azteca. Bulletin of Environmental Contamination and Toxicology. 82(6):777-780. Interpretive Summary: Pesticides contained in agricultural runoff can damage downstream receiving systems, such as rivers, lakes, and streams. One suggested alternative is to run pesticide-laden runoff through rice fields (which serve as a constructed wetland). Results indicated that the rice plants were able to filter diazinon down to concentrations which were less toxic to laboratory organisms. For organisms exposed to water from unvegetated systems, the toxicity remained relatively high. This study demonstrates the importance of vegetation in reducing pesticide concentrations before they reach aquatic receiving systems.
Technical Abstract: This study assessed the viability of using planted, mature rice fields in mitigating diazinon (an organophosphate insecticide) runoff toxicity using aqueous 48 h Hyalella azteca whole effluent toxicity bioassays. Rice fields decreased diazinon concentrations 80.1-99.9% compared with 10.8% in the unvegetated field control. H. azteca survival responses coincided with observed diazinon concentrations. Estimated LC50 effects dilutions (%) ranged from 1.15-1.47 for inflow samples and 1.66 (unvegetated), 6.44 (rice field A) and >100 (rice field B) outflow samples. Decreases in inflow versus outflow aqueous toxicity were 77.1-100% in rice fields compared with 18.7% in the unvegetated field.