Location: Water Quality and Ecology ResearchTitle: Drying and storage methods affect cyfluthrin concentrations in exposed plant samples Author
Submitted to: Bulletin of Environmental Contamination and Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/17/2016
Publication Date: 5/25/2016
Citation: Moore, M.T., Kroger, R., Locke, M.A. 2016. Drying and storage methods affect cyfluthrin concentrations in exposed plant samples. Bulletin of Environmental Contamination and Toxicology. 2016;97:244-248 DOI 10.1007/S00128-016-1835-2. Interpretive Summary: No definitive standard procedure exists for drying and storage of plant samples prior to pesticide analysis. Fourteen possible combinations of drying and storage methods were compared with plant material exposed to a particular insecticide. The control method, consisting of mechanical freeze drying followed by immediate analysis, was significantly more efficient than the other 14 combinations of drying and storage. However, encouraging results were seen among the 14 combinations. In cases where a mechanical freeze dryer is not available, plant samples can be initially stored in a freezer for 7 d, dried in a greenhouse for 7 d, then stored in a freezer for up to 30 d before analysis and still recover the majority of exposed cyfluthrin. Since immediate pesticide analysis is not always an option due to logistical, financial, or equipment constraints, this research gives scientists various drying and storage options to maximum pesticide concentrations recovered from plant samples. Future studies should perform comparable analyses on various pesticide classes to determine possible similar relationships.
Technical Abstract: Standard procedures exist for collection and chemical analyses of pyrethroid insecticides in environmental matrices. However, less detail is given for drying and potential storage methods of plant samples prior to analyses. Due to equipment and financial limitations, immediate sample analysis is not always possible. The goal of the current research was to determine which plant drying and storage method yielded the highest cyfluthrin recovery rates compared to traditional mechanical freeze-drying methods. Fifteen, circular polyethylene mesocosms (0.41 m depth x 0.28 m radius) were established with Lexington silt loam soil (0.25 m) and planted with rice (Oryza sativa). A one-time exposure of cyfluthrin (target 5 mg L-1) was amended into the water column of individual mesocosms. Forty-eight hours after the amendment, plant material exposed in the water column was collected from each of the 15 mesocosms. Control (mechanical freeze drying) recovery of cyfluthrin was significantly greater (p < 0.001) than all 14 possible combinations of drying and storage. Significant differences also existed between the 14 combinations for cyfluthrin-plant concentrations. Aside from the control, greatest cyfluthrin recoveries in plants were collected in the freezer-greenhouse-freezer drying and storage method. Results provide evidence for the most efficient drying and storage methods for plant samples contaminated with cyfluthrin. Future studies should perform comparable analyses on various pesticide classes to determine possible similar relationships.