Protocol for the Derivation of Environmental and Human ... - CCME

Part B, Section 7
where: FIR = he food ingestion rate for the species used in the DTED (kg dw food/day)
DMIR = geometric mean of the dry matter intake rate for the species used in the
DTED (kg dw/day)
SIR = the soil ingestion rate (kg dw soil/day)
If no DMIR information is available, then allometric equations (Nagy, 1987) should be used to estimate
the FIR according to the following equations. Note: equations have been converted from g dw
food/day to kg dw food/day.
For mammalian species, the allometric equation is:
F M = 0.0687 × (BW) 0.822
where: F M = feeding rate of mammalian species (kg dw food/day)
BW = mean body weight in kilograms (kg) of the species used to derive the DTED
For avian species, the allometric equation is:
F A = 0.0582 × (BW) 0.651
where: F A = feeding rate of avian species (kg dw food/day)
BW = mean body weight in kilograms (kg) of the livestock or wildlife species used to
derive the DTED
7.6.5 Determining Bioavailability
The bioavailability of soil-adsorbed contaminants in the species used to calculate the DTED should be
estimated. Due to lack of specific information on the bioavailability of contaminants from ingested soil
for livestock and terrestrial wildlife, a bioavailability factor of one is assumed. However, if information
exists to support an alternative bioavailability factor (BF), it should be incorporated into the calculation
of the guideline.
7.6.6 Determining Bioconcentration Factors
The development of soil quality guidelines for herbivore food ingestion requires that a concentration of a
substance in soil be established that will not lead to adverse effects to receptors from the ingestion of
forage material. One way of doing this, in a generic equation, is to extrapolate to a concentration in soil
using soil-to-plants bioconcentration factors (BCFs). Bioconcentration factors are used to estimate the
concentration of contaminants in biota contributed from the media directly. In essence these factors
estimate the amount of a substance that is bioavailable and can be concentrated in biota.
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