Evaluating wipe sampling parameters to assess method performance and data confidence during remediation of hazardous pesticide misuse chemicals on indoor materials

Abstract

Pesticide misuse incidents are reported worldwide each year. The potential exposure to pesticides creates a concern for occupants in affected homes, apartments, and other occupied buildings. Pesticides that are improperly applied within these locations may require remediation prior to reoccupation. Incident response personnel rely heavily on data from sampling results to identify residue levels and determine when site remediation is complete. Surface wipe samples are often collected for this purpose. Therefore, it is important to ensure sampling and analysis procedures are well established for the contaminants of concern, particularly for wipe sampling variables that can affect analysis results. This investigation evaluated the effects of surface wipe media, wipe wetting solvents, pesticide concentrations effects, composite sampling, surface types, and pesticide formulation effects on analysis results for fipronil, permethrin, and deltamethrin. Tested surface types included galvanized steel, vinyl tile, and plywood. Wipe media included pre-packaged, sterile cotton gauze, pre-cleaned cotton twill, and a pre-packaged, pre-wetted wipes. Surface recovery results are reported for commercially available fipronil formulations and compared to technical grade fipronil solutions. Fipronil recoveries were 92–107 % for twill wipes, 81–98 % for cotton gauze wipes, and 79 % for pre-packaged, pre-wetted wipes on a galvanized steel surface. Permethrin recoveries were 83–116 % for twill wipes, 66–94 % for cotton gauze wipes, and 73 % for pre-packaged, pre-wetted wipes on a galvanized steel surface. Deltamethrin recoveries were 67–88 % for twill wipes, 55–71 % for cotton gauze wipes, and 63 % for pre-packaged, pre-wetted wipes on a galvanized steel surface. The data collected in this study can inform surface wipe sampling methods and potentially assist in obtaining more accurate sampling data associated with pesticide misuse incidents involving the target analytes.