where SF is the cancer slope factor of carcinogen as listed in
Table S2. If there is more than one carcinogenic contaminant, the
cancer risks from all carcinogen and exposure routes are summed
to assess the total potential cancer risks (assuming additive effects).
Risks in the range of 1.0 106 to 1.0 104 are regarded to be
acceptable. Cr, Cd, As, Ni and Co were treated as potential carcinogenic
contaminants, whereas other metal(loid)s were regarded
as non-carcinogenic, on the basis of the order of classification group
defined by the International Agency for Research on Cancer (IARC,
2011). The exposure factors such as RfD are listed in Table S2.