A preliminary examination of the translocation of microencapsulated cyfluthrin following applications to the perimeter of residential dwellings

Methods have been developed to monitor the translocation of microencapsulated cyfluthrin following perimeter applications to residential dwellings. A pilot study was implemented to determine both the potential for application spray to drift away from dwellings and the intrusion of residues into homes following perimeter treatments. Residential monitoring included measuring spray drift using cellulose filter paper and the collection of soil samples from within the spray zone. In addition, interior air was monitored using fiberglass filter paper as a sorbent medium and cotton ball swabs were used to collect surface wipes. Fortification of matrixes resulted in recoveries of > 90%. Spray drift was highest at the point of application and declined to low but measurable levels 9.1 m from the foundations of dwellings. Soil residues declined to low, but measurable levels by 45 days post-application. No cyfluthrin was measured from indoor air; however, some interior surfaces had detectable levels of cyfluthrin until three days post-application. Findings indicate that spray drift resulting from perimeter applications might contaminate non-target surfaces outside the spray zone. Soil borne residues may serve as persistent sources for human exposure and potentially intrude into dwellings through the activities of occupants and pets. Residues do not appreciably translocate through air and consequently inhalation is not a likely route for human exposure. Surface residues detected indoors suggest that the physical movement of residues from the exterior to the interior might be a viable route of movement of residues following this type of application.