Pierre River Mine Project

HEALTH AENV SIRS 79 – 89
Section 14.1
Table AENV 86-5: Chronic Lifetime and Incremental Lifetime Cancer Risks per 100,000
from Multiple Pathways of Exposure – Aboriginal 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 3.2E-12 2.6E-11
arsenic 2.0E+01 3.2E-03 2.6E-01
carbon tetrachloride 1.3E-01 7.4E-13 2.2E-11
carcinogenic PAH group 1 4.9E-01 1.9E-01 2.1E-01
carcinogenic PAH group 2 6.1E-02 8.0E-02 8.7E-02
carcinogenic PAH group 3 1.2E-02 4.5E-03 4.7E-03
Mixtures (c)
stomach carcinogens 5.6E-01 2.7E-01 3.0E-01
liver carcinogens 2.1E+01 3.2E-03 2.6E-01
Note:
(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. With scientific notation, any value expressed to the negative power (i.e., E-x) shows that predicted
exposures were less than the exposure limit; whereas, a value expressed to the positive power (i.e., E+x) shows
that exposure estimates exceeded the exposure limit.
(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. With scientific notation, any value
expressed to the negative power (i.e., E-x) shows that predicted exposures were less than the exposure limit;
whereas, a value expressed to the positive power (i.e., E+x) shows that exposure estimates exceeded the
exposure limit.
(c) Individual constituents of the chemical mixtures are identified in EIA, Volume 3, Section 5.3.2.3, Table 5.3-13.
Manganese
Risk quotients above 1.0 (i.e., 1.3) were predicted for cabin and Aboriginal
residents under the Base Case, Application Case and Planned Development Case
(PDC). In the HHRA, RQ values of 0.19 and 1.6 were predicted for the cabin and
Aboriginal residents, respectively.
Interpretation of these findings considered the following factors:
• the potential contribution from the project to these predicted exceedances;
• the primary exposure pathway(s) contributing to these predicted
exceedances;
• the use of the 95th upper confidence interval on the mean (95UCLM) of
concentrations of manganese in various media versus the average
concentration; and,
April 2010 Shell Canada Limited 14-29
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