title: MRL calculations based on both intra- and inter-trial residue variability.
abstract: Methods for calculating maximum residue levels or, at least, high percentile values (e.g. 95th percentile) to support the estimation have been developed in recent years. A mathematical equation is proposed that, for a set of supervised pesticide residue trials on a crop, expresses the incidence of residues as a function of residue concentration in the food commodity. Each residue concentration is expressed as a population reflecting its intra-trial variability. The equation is then the sum of these sub-populations to represent the set of trials, a population of sub-populations (POSP). The equation is formulated so that the area under the curve precisely equals the number of trials. Calculation of a residue concentration corresponding to a percentage of the area under the curve produces the required percentile. Results are generally consistent with the current OECD method calculation. The POSP calculation will be a useful tool in estimating maximum residue levels, where the first choice, other matters being acceptable, would be a value between the 95th and 99th percentiles. Replicate data are directly accommodated in the calculation. The POSP calculator can answer such questions as: what percentile corresponds to the highest residue (HR) in the residue data set?
authors.affiliation: Queensland Department of Primary Industries, Brisbane, Australia. Electronic address: denisjhamilton@gmail.com.
authors.forename: Denis J
authors.initials: DJ
authors.lastname: Hamilton
mesh_terms: D018556:Crops, Agricultural / Q000737:chemistry*; D005506:Food Contamination / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*
chemical_list: D010573:Pesticide Residues
keywords: JMPR; POSP equation; Pesticide MRL; Supervised residue trial