Deposition of malathion and permethrin onto grass surfaces, after ultra-low volume (ULV) application, was studied in a suburban neighborhood in Saginaw County, Michigan. Commercial concentrates of malathion (Cythion ULV) and permethrin (Biomist 4 + 12) were sprayed using a truck-mounted ULV aerosol generator. Sod-grass blocks (0.18 m2) were placed in the frontyard and backyard of homes in the neighborhood at 4 distances to 91.4 m from the road where applications were made. Grass samples were taken from the sod blocks before application and at 15 min, 12 h, 24 h, and 36 h after application. Samples were extracted with solvent, and extractions were subjected to gas-liquid chromatography for detection of malathion and permethrin. Ranges of detection for malathion were 0.0-16.6 mg/0.18 m2 and for permethrin were 0.0-25.9 mg/0.18 m2. Most detections were from samples taken nearest the road at 15 min after application. Detections declined as a logarithmic function of time after application and as an exponential function of distance from the road.
