Autors: Árpád Ambrus, Zsuzsa Farkas, Zsuzsanna Horváth, Gabriella Suszter
This paper reviews the information available on the characteristics of the distribution of pesticide residues in primary and composite samples of sizes specified by relevant standards. Residue data measured in >19000 crop units, 144 composite samples taken from commercially treated crops, supervised trials samples taken from 1900 crop-pesticide combinations, >1200 duplicate samples taken from supervised trials were evaluated and complemented with numerous computer modelling for the determination of typical sampling uncertainties for 19 commodity groups. In case of potentially mixed lots, it is appropriate to multiply the typical sampling uncertainties with a factor of 1.4.
For the pre-marketing testing of compliance, the expanded combined uncertainty including the uncertainty of sampling and the reproducibility of analyses should be taken into account.
It is recommended to establish an action limit, which is lower than the authorised maximum residue limit, for pre-marketing testing of pesticide residue concentrations in plant commodities. The application of an Excel macro facilitating the calculation is illustrated with practical examples.
Distribution of pesticides and residue concentrations remaining on the crops are influenced by several factors that can only be regulated partially by the persons performing the treatment, even under ideal conditions. Factors influencing residue distribution were summarized in detail by Horváth et al., based on available literature data . In our publication, typical factors resulting in significantly different residue concentrations in certain crops or microregions during practical implementation are illustrated with a few examples
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