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

Appendix B
Assuming that dairy cattle ingest, on average, 0.9 kg of soil per day (Fries and Paustenbach. 1990), and
that chemical intake via vegetation is negligible compared to that with direct soil intake, then the daily
intake of chemical can be defined as:
daily chemical intake by dairy cattle = C s × 0.9 kg/day [9]
Where C s is the concentration (mg/kg) of the chemical in the soil.
Substituting equation 9 into the definition of B m and the latter into equation 8, and assuming that C s is the
proposed preliminary soil quality guideline (PSQG HH ), and rearranging the equation, then the potential
concentration of the organic chemical in milk (C m ) can be defined as:
C m = antilog(-8.1 + log K ow )(day/kg) × PSQG HH (mg/kg) × 0.9(kg/day) [10]
3.4 Human Daily Intake of Contaminants from Milk
Intake resulting from contaminated milk can be defined as:
I m = (MK h × MK c × B m × PSQG HH ) + (MK s × MK c × MK r ) [11]
BW
Where:
I m = total intake of contaminants from milk (mg/kg⋅day)
MK h = percentage milk home produced
MK c = milk consumption rate (kg/day)
B m = biotransfer factor for milk
PSQG HH = preliminary human health-based soil quality guideline (mg/kg)
MK s = percentage milk purchased
MK r = average chemical concentration in retail milk (mg/kg)
For non-carcinogens, the receptor is assumed to be a 13 kg child consuming 632 g of milk (whole, 2%
and skim milk) per day. For carcinogens, the receptor is assumed to be a 70 kg adult consuming 230 g
per day (Health Canada, 1994). For agricultural land use, 100% of all milk is assumed to be produced
on site (Table B.1).
4.0 Soil Guidelines Checking Procedure
The calculated contaminant concentration must be less than the required Maximum Residue Limit
(MRL), when available, as specified in the Food and Drug Act. If the calculated concentration is
higher, then the preliminary soil quality guideline must be lowered. This checking mechanism applies to
both carcinogenic and non-carcinogenic compounds.
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