Concentrations calculation

Substance conversions data 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 may be applicable, e.g., when a measured substance represents multiple substances and measurements of this measured substance 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 and one may need points of departure or relative potency factors when the substance conversion should select the most toxic candidate in case a measured substance translates to multiple active substances.

In some cases, it may be that for a certain food/substance combination, there are few measurements in the concentration data. In this case, extrapolation of concentration data may be desired. If this is the 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 concentrations data, but it may be desirable to include water concentrations 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.

Calculators

• Substance conversion
• Food extrapolation
• Water imputation