Transferability of six pesticides from agricultural sprayer surfaces

Secondary exposure to pesticide residues on the external surfaces of sprayers does not currently form part of the risk assessment process. A measure of the ease with which residues may be transferred from the sprayer surface to the operator would enhance the accuracy of any such assessment. This study quantified the dislodgeability of six pesticides from sprayer surfaces in order to calculate the transfer efficiencies. The transfer efficiency was compound dependent, ranging from 80% for azoxystrobin to <25% for flusilazole and tebuconazole. When the washed and unwashed surfaces were analysed separately, more pendimethalin and isoproturon residues were removed from the wet surface compared with the dry surface. The variation in results for the different compounds highlights the need to consider a range of compounds to form generic statements to support guidelines regarding operator exposure to pesticide residues on sprayers.