Kinetic modules

Kinetic models convert exposures or hazard characterisations from one or more external routes or compartments to an internal compartment or biological matrix. Internal exposure can be systemic or related to a specific biological matrix in a kinetic model (target). The reverse conversion from internal to external is called reverse dosimetry.

In a simple tier, kinetic models are specified as absorption factors (systemic). In a higher tier, physiologically based (toxico)kinetic (PBK) models of a specified type (currently available is the EuroMix generic PBK model) are linked to MCRA. Kinetic model instances for specific substances and test systems (e.g. cypermethrin in the rat) are specified with parameter sets for the chosen kinetic model.

There are 3 tiers for relating external to internal exposures (doses):

  1. Assume conservative absorption factors as suggested by EFSA (EFSA (2014), EFSA (2017a)): oral and inhalation 100%, dermal 50%. The internal exposure is systemic (absorption factors data tables).

  2. Use externally provided kinetic conversion factors, converting the exposure to an internal target (biological matrix) or organ (kinetic conversion factors data tables).

  3. Use one of the implemented PBK models, with instances for specific substances defined in data table kinetic model instances and model parameters specified in data table kinetic model instance parameters.

Given a chosen tier, the calculation will fall back to the next lower tier in case of missing data.