Determination of bystander exposure to pesticide spray drift: methodology proposal.

The potential spray drift exposure of bystander and residents from orchard pesticide applications is likely to be higher than from boom sprayers, especially in Italy where the close interconnection between urban and rural areas amplify this phenomenon. On request of European Commission the European Food Safety Authority (EFSA) established a working group (WoG) for revising all available data and procedures to perform the operator, worker, resident and bystander pesticide risk assessment (EFSA, 2014). For orchard crops and vines, the most used dataset is Lloyd et al. (1987). The WoG recommended that further data shall be produced to refine the proposed assessment. Besides having limited data available at present there is no standardized method for collecting data on resident and bystander pesticide contamination. The aim of this work was to assess the efficiency of different collectors types and the different test layouts, in order to evaluate the better solution for detecting the pesticide exposure of bystanders during plant protection product (PPP) application and to propose a test methodology that may be combined with the existing ISO22866 standard methodology for arable crop pesticide drift measurement. The proposed methodology has been applied in field experiments undertaken in 2013 and 2014 measuring spray drift deposits on mannequins (coveralls and synthetic filter clothes collectors) and airborne spray drift (Petri dishes, vertical polythene line collectors). The results obtained have underlined a lacking relationship between different type of collectors, underlining the need of an appropriate experimental framework able to define the most suitable collectors type and layout to be used.