Concentrations calculationΒΆ
Occasionally, concentrations of substances measured in food samples are exceeding a specified concentration limit e.g. the Maximum Residue Limits (MRL). An MRL is the highest level of a substance that is legally tolerated in or on food or feed when substances are applied correctly. Filter samples exceeding the concentration limits filter out all samples where one of the substances measured is exceeding the MRL.
Substance conversions rules may be used to convert concentration data at the level of measured substances to concentration data at the level of potentially active substances. These rules (provided as data) may be applicable, for example, when a measured substance represents multiple substances and these measurements should be converted into measurement values for these substances. This conversion may depend on substance authorisations which provides information on the likelihood of certain translations to occur. points of departure or relative potency factors might be needed when the substance conversion should select the most toxic candidate in case a measured substance translates to multiple active substances.
If there are only a few measurements in the concentration data, then extrapolation of concentration data may be desired. In that case, food extrapolation rules may be provided to specify per food the alternative foods from which extrapolation is allowed. The extrapolation of concentrations will then be performed within this module and the results are included in the resulting active substance concentrations data. Substance authorisations and/or concentration limits may be used to further restrict the to-food/from-food combinations per substance for which extrapolation is possible.
Concentration data for water are often not available in the concentration data, but it may be desirable to include them in the assessments. For this, imputation of low-tier, deterministic estimates of water concentrations of the most toxic substances may be used to include (typically conservative) estimates in the calculations.
In some scenarios it may be desired to perform a prospective analysis in which anticipated (or foreground) focal commodity concentration data for a particular focal commodity food (and substance) is added to, or replaces part of the background concentration data that is used for the null-scenario. The concentrations module offers various options to perform such focal commodity scenario analyses.
It is also possible to filter (or subset) samples by specific sample properties (e.g., year, location). This can be done by checking the option to filter samples by specific property values (subset selection).