Pierre River Mine Project

HEALTH AENV SIRS 79 – 89
Section 14.1
As shown in Table AENV 86-4 and Table AENV 86-5, the maximum predicted
incremental lifetime cancer risks (ILCR values) associated with the project (i.e.,
Application Case minus Base Case) and Future Emission Sources in the area
(i.e., PDC minus Base Case) are all less than one in 100,000 indicating that the
incremental cancer risk from the project and planned development is deemed to
be “essentially negligible” (Health Canada 2004).
Although lifetime cancer risks (LCR values) greater than 1.0 were predicted for
the Base Case assessment of arsenic and the “liver carcinogen” mixture, these
values represent the number of cancer cases that could theoretically result from
the estimated exposures to these carcinogenic COPCs in a population of 100,000
people. Lifetime cancer risks for arsenic and the “liver carcinogen” mixture were
also found to exceed 1.0 in the HHRA (EIA, Volume 3, Section 5.3.3.3,
Table 5.3-42 and Table 5.3-43).
The predicted LCR values for arsenic and the “liver carcinogen” mixture are
discussed below.
Table AENV 86-4: Chronic Lifetime and Incremental Lifetime Cancer Risks per 100,000
from Multiple Pathways of Exposure – Cabin Residents
Chemical of Potential
Concern Base Case
Lifetime Cancer
Risk (a) Incremental Lifetime Cancer Risk (b)
Project
(Application-Base)
Future Emission
Sources
(PDC-Base)
1,1,2-trichloroethane 9.8E-01 4.8E-13 4.3E-13
arsenic 1.9E+01 3.7E-03 2.6E-01
carbon tetrachloride 1.3E-01 8.3E-13 1.5E-12
carcinogenic PAH group 1 5.7E-01 2.0E-01 2.1E-01
carcinogenic PAH group 2 7.8E-02 9.0E-02 9.6E-02
carcinogenic PAH group 3 1.3E-02 4.6E-03 4.9E-03
Mixtures (c)
stomach carcinogens 6.6E-01 2.9E-01 3.1E-01
liver carcinogens
Note:
2.0E+01 3.7E-03 2.6E-01
(a) Lifetime cancer risks refer to the number of cancer cases that could potentially result from the estimated exposures
to the carcinogenic COPCs among a population of 100,000 people. Since an acceptable cancer incidence rate has
not been recommended for exposure to carcinogens associated with anything other than the Project and Future
Emission Sources by any leading scientific or regulatory authority, interpretation of the significance of the LCR
values determined for the Base Case could be not based on comparison against a numerical “benchmark” of one
in 100,000.
(b) An ILCR equal to or less than 1.0 signifies an incremental lifetime cancer risk that is below the benchmark ILCR of
one in 100,000 (i.e., within the generally accepted limit deemed to be protective of public health). Boldface values
show an ILCR of greater than the de minimus risk level of one in 100,000.
(c) Individual constituents of the chemical mixtures are identified in EIA Volume 3, Section 5.3.2.3, Table 5.3-13.
14-28 Shell Canada Limited April 2010
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