Introduction to MCRA
Humans are exposed to a mixture of multiple chemicals via food intake, inhalation and dermal contact. The risk to health that may result from this depends on the effects of different chemicals in the mixture and how they combine.
MCRA is the model and data toolbox developed in the EuroMix project. It implements methods for exposure, hazard and risk assessment, following guidelines from a.o. the Joint Research Centre (JRC) of the European Commission and the European Food Safety Authority (EFSA). The toolbox should provide computational tools for future risk management decisions on the safety of chemicals in mixtures to be taken by the European Commission and the Codex Alimentarius.
MCRA is a collection of data and models. The system consists of modules that are arranged in eight categories according to a modular design. See Modules overview.
Each module represents a certain type of data, which can be computed from data provided by other (sub)modules, or the data may be obtained from a dataset selected from the data repository. Likewise, each module may be of interest by its own merit, or may just be required as a sub-part of larger calculations. The modular design of MCRA reveals a network of data and models, and shows how data of types and from various sources can be combined in overarching modules. The most overarching module is Risks or health impact estimates. The toolbox allows the user to start in any of the modules in the modular design for performing calculations.
For each module, an action can be created to configure and run the module. For data modules, such as the concentrations module, such an action comprises specifying the dataset, specifying the scope (i.e., foods of interest, substances of interest, etc.), and perhaps specifying specific selections or model settings for data manipulations (e.g., imputation of water concentrations in the concentrations module). For calculation modules, when calculating the data of the module based on other data, configuration of an action comprises specification of the model settings and selection of the calculation inputs, which is data provided by other (sub-)modules. While running an action in MCRA, the module produces output of its associated data type (which can be used as input for other modules), and a report will be generated of the selected data, the selection and model settings, and the module and all intermediate (i.e., sub-modules) results.