Pierre River Mine Project

HEALTH AENV SIRS 79 – 89
Question No. 89
Request Volume 2, SIR 99a, Page 18-130.
Section 14.1
Shell notes that, for aliphatic C5-C8 compounds and aromatic C9-C16 compounds,
the use of a less conservative relative absorption factor (RAF) does not affect the
predictions in the HHRA.
89a Re-assess these compounds using the CCME recommended value of 0.2 in order
to quantitatively prove this conclusion.
Response 89a The aliphatic C5-C8 group and aromatic C9-C16 group were re-assessed using the
CCME dermal relative absorption factor (RAF) of 0.2. The updated risk
quotients (RQ values) for the aliphatic and aromatic group are presented for each
of the lifestyle categories evaluated as part of the multiple pathway assessment
(i.e., cabin residents, Aboriginal residents, community residents and workers).
Updated RQ values are also provided for the cabin and Aboriginal residents that
consider an alternative consumption pattern to that used in the HHRA (i.e., 100%
of their food would be obtained from local, natural sources), as further discussed
in the response to AENV SIR 86.
As shown in Table AENV 89-1, use of the CCME RAF value did not materially
change the results or the conclusion of the HHRA. The updated multiple pathway
RQ values for the aliphatic C5-C8 group and aromatic C9-C16 group did not
exceed 1.0 under any circumstance. This demonstrates that the estimated
exposure remains less than the exposure limit (i.e., the assumed safe level of
exposure). Therefore, health risks for the aliphatic C5-C8 group and aromatic C9-
C16 group remain low.
14-36 Shell Canada Limited April 2010
CR029