Residue crop foliage, estimating

In conclusion it can be stated that the basic assumptions of the re-entry model — a linear relationship between application rate and initial dislodge-able foliar residue and a first-order decay of the DFR — have been confirmed. The relationship between the transfer factor and re-entry time at various DFR levels should be explored further. Including information on foliage surface area or crop density may lead to a refinement of the model however, crop volume estimating methods should be improved before their influence on the exposure processes can be fully evaluated. 

Gunther, F. A. Iwata, Y. Papadopoulou, E. Berck, B. Smith, C. A. Rapid field method for estimating organo-phosphorus insecticide residues on crop foliage. Bui1. Environm. Contam. Toxicol., 1980, 24, 903. 

Methamidophos is an insecticide that is used on foliage and is therefore often detected in RACs (cotton and tomato) at harvest. Therefore, the residue values used for calculating possible dietary exposure are considered reasonable estimates rather than worst-case ones. For chronic exposure, the percentage of crop treated factor has been used, which will have the effect of reducing chronic dietary exposure and increasing the MOE values. 

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