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

Part B, Section 7
Where the ECL lies in relation to the range of effects data for cadmium is shown in Figure 11. The
ECL is calculated according to the following equation:
ECL = (LOEC 1 × LOEC 2 × ... × LOEC n ) 1/n
where ECL = effects concentration low (mg/kg)
LOEC = lowest observed effect concentration (mg/kg)
n = the number of available LOECs
A minimum of three studies reporting LOEC endpoints must be considered, and data must include
values for at least one terrestrial plant and one soil invertebrate study. Given that the LOEC method
produces a mean value, subject to data variation inherent in multi-species toxicity data, it may be
appropriate to apply a limited uncertainty factor in view of the range of species sensitivities, and the level
of protection sought for these two land uses. In the case where an uncertainty factor is deemed
appropriate, a value between one and five should be used.
The ECL should now be compared with the microbial value to determine the SQC SG for commercial
and industrial land use (See Appendix A).
No median effects method is recommended for guidelines derivation for commercial and industrial land
use. Because uncertainty factors are not applied at the point of departure from the effects distribution,
the ECL would therefore be estimated at a level of median effects, which is contrary to the level of
protection desired at the level of the ECL.
7.5.3.5 Insufficient Data for Soil Contact Guidelines Derivation. If minimum data requirements
for the LOEC method cannot be met, no soil contact guideline shall be set for commercial and industrial
land use. Data gaps will be identified for further research.
7.6 Derivation of Soil Quality Guidelines for Soil and Food Ingestion
The procedure for deriving soil quality guidelines for ingestion of soil and food (SQG I ) by grazing
livestock and wildlife on agricultural lands is described in this section. Current knowledge of effects to
terrestrial receptors from the ingestion of contaminated soil and food is best understood, with some
exceptions (e.g. some insectivores), for herbivores (livestock and wildlife) grazing on agricultural lands
and is considered to be the most significant route of contaminant exposure to these receptors (Thorton
and Abrahams, 1983; Fries, 1987; Paustenbach, 1989). This procedure also accounts for the
consumption of contaminated forage via the accumulation of contaminants in the food chain. Because
this procedure is limited to a herbivore food chain, chemicals that bioaccumulate in the tissues of plants
and that can be transferred in the food chain are of primary importance.
In view of the data requirements and model parameters used to estimate generic guidelines for soil and
food ingestion, it is only possible to derive ingestion guidelines where data are sufficient to keep model
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