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

Part D, Section 1
Section 1
Derivation of the Final Soil Quality Guideline
1.1 Final Guideline Derivation
The final recommended soil quality guideline (SQG F ) is to protect both ecological and human health.
The preliminary human health soil quality guideline, which have been modified to ensure protection of
human health with respect to the check mechanisms outlined in Part C and relevant appendicies,
become the recommended human health-based soil quality guidelines (SQG HH ). Appropriate
annotations will accompany any SQG HH that are based on modified PSQG HH .
The lower of the two guidelines obtained through the environmental procedure (SQG E ) (Part B), or
human health based procedure (SQG HH ) (Part C), will be recommended as the final soil quality
guideline (SQG F ) for each land use subject to restrictions discussed in Section 1.2 (Part D) below. A
general overview of the entire guidelines derivation process outlining the major steps leading to
derivation of the final soil quality guideline is illustrated in Figure 24.
1.1.1 Evaluation Against Plant Nutritional Requirement, Geochemical Background and
Analytical Detection Limits
The SEQCCS believes that guidelines should be reasonable, workable and usable. Guidelines are
developed by applying scientifically derived information, backed by professional judgement where data
gaps occur. Occasionally, defined exposure-based procedures produce numerical guidelines that
conflict with one or more of the following:
• plant nutritional requirements;
• geochemical background;
• analytical detection limits;
When a conflict of this type occurs, guidelines must be adjusted as described below:
Some chemicals (e.g., copper and zinc) considered hazardous at high levels also provide minimum
nutritional requirements for the maintenance of plant growth at lower levels. The SEQCCS
acknowledges that the SQG F determined for these chemicals may fall below the nutritional
requirements. For agricultural and residential/parkland land uses maintenance of nutritional requirements
is critical to sustaining the primary activity on these lands (i.e., growing crops, grass, trees). Accordingly,
SEQCCS recommends that the SQG F for these land use categories be compared to minimum plant
nutritional requirements. If the SQG F is below acceptable minimum plant nutritional requirement levels,
then insufficient nutritional requirements for plant growth may result at the value of the SQG F . The
SQG EE should therefore default to the soil concentration required for minimum plant nutrition. This value
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