Field Study Conduct
The most significant studies conducted by ARTF were its worker reentry exposure studies. In these studies, workers were dressed in standard clothing while they performed their normal activities after a field was sprayed with a surrogate compound. At the end of the day, the amount of residue from the surrogate compound was measured on the clothing, and also on the face and hands. At the same time, leaf samples from the crop were collected and washed in a detergent solution. The amount of residue in the wash solution, from which the residue on leaf surfaces was calculated, is the Dislodgeable Foliar Residue (DFR). The ratio of residues on the clothing to the residues washed off the leaves is the Transfer Coefficient (TC).
Field reentry studies were conducted on activities within each of the crop/activity cluster groups. ARTF conducted 27 reentry exposure studies which, with the 18 purchased studies, should provide enough generic TC data to complete the database.
The ARTF member companies individually are conducting product-specific DFR studies, in which leaf samples from a treated field are collected and washed in the same manner as in the exposure studies to determine the product-specific DFR. As noted above, ARTF’s generic TCs will be applied to product-specific DFR data to assess potential reentry exposure to that product at any time following application.