Soil exposures calculation details
The long term (chronic) soil exposure assessment is assessed as oral exposure related to exposure to substances in soil. MCRA applies in principle the equations as used in RSExpo.
Soil exposures are generated using properties age and sex of a simulated set of individuals or, as an alternative, an existing set of individuals (currently, the dietary individual population, see module dietary exposures). Specify the reference population with option Specify individuals for generating soil exposures with settings Simulate individuals or Use dietary individuals.
Note that table Soil bioaccessibility fractions is not mandatory. If the table or its substances are missing from the upload, default bioaccessibility fractions equal to 1 will be used by default.
Oral exposure
The calculation for oral exposure is:
Parameters used in the equation
\(\mathtt{E_{soil-ing}}\) : average daily external exposure of an individual to substances by soil ingestion (\(\mu g/kg \, bw /day\))
\(\mathtt{BW}\): body weight of the individual (default in \(kg\))
\(\mathtt{q_s}\): average daily amount of soil ingested by the individual (default in \(g/day\))
\(\mathtt{c_s}\): substance concentration in soil (default in \(\mu g/g\))
\(\mathtt{b_s}\): oral bioaccessibility of the substance, i.e. fraction of the substance that is extracted from soil particles by saliva and digestive fluids in the gastro-intestinal tract, [0, 1]. When omitted a default bioaccessibility fraction equal to 1 will be used.