Formulation effects and the off-target transport of pyrethroid insecticides from urban hard surfaces.
Controlled rainfall experiments utilizing drop-forming rainfall simulators were conducted to study various factors contributing to off-target transport of off-the-shelf formulated pyrethroid insecticides from concrete surfaces. Factors evaluated included active ingredient, product formulation, time between application and rainfall (set time), and rainfall intensity. As much as 60% and as little as 0.8% of pyrethroid applied could be recovered in surface runoff depending primarily on product formulation, and to a lesser extent on product set time. Resulting wash-off profiles during one-hour storm simulations could be categorized based on formulation, with formulations utilizing emulsifying surfactants rather than organic solvents resulting in unique wash-off profiles with overall higher wash-off efficiency. These higher wash-off efficiency profiles were qualitatively replicated by applying formulation-free neat pyrethroid in the presence of independently applied linear alkyl benzene sulfonate (LAS) surfactant, suggesting that the surfactant component of some formulated products may be influential in pyrethroid wash-off from urban hard surfaces.
Jorgenson
Brant C
BC
Agricultural and Environmental Chemistry Graduate Group and Department of Civil and Environmental Engineering, University of California at Davis, Davis, California 95616, USA.
Young
Thomas M
TM
D017738:Alkanesulfonic Acids / Q000737:chemistry; D002625:Chemistry, Organic / Q000379:methods; D002947:Cities; D003198:Computer Simulation; D004784:Environmental Monitoring / Q000379:methods*; D007306:Insecticides / Q000032:analysis*; D007700:Kinetics; D009930:Organic Chemicals / Q000032:analysis; D010573:Pesticide Residues / Q000032:analysis*; D011722:Pyrethrins / Q000032:analysis* / Q000737:chemistry; D011891:Rain; D013501:Surface-Active Agents / Q000737:chemistry; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry*
D017738:Alkanesulfonic Acids; D007306:Insecticides; D009930:Organic Chemicals; D010573:Pesticide Residues; D011722:Pyrethrins; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; C030641:alkylbenzyl sulfonic acid; C099952:bifenthrin