Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1:p7
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1 (pt 7/13)
Character Range: 2382701–2385579

No inhalation assessment is provided by RIVM.

CCME (2008)         SF = 2.3 (mg/kg/day)-1                    Oral SF derived from a less than lifetime diet study on inbred CFW-Swiss mice associated with incidence of papillomas and squamous cell carcinomas and linear extrapolation. This is the same study as used by US EPA in the derivation of its oral slope factor. The CCME review also noted that dermal exposures and primary oral exposures result in different kinds of cancers. Health Canada is currently reviewing data with respect to the derivation of a dermal cancer slope factor, which may require consideration when peer-reviewed and published. The oral slope factor has been used to derive a soil guideline associated with exposures via oral, dermal and inhalation exposures.

OEHHA (CEPA 1999)   SF = 11.5 (mg/kg/day)-1                   Oral SF derived using the same model and study as reported by US EPA (IRIS 2012) and CCME (2008), with the upper end of the range of values adopted by OEHHA.
                    UR =0.0011 to0.0033 (ug/m3)-1             Inhalation UR derived on the basis of respiratory tract tumours in an inhalation study in hamsters and a linearised multistage model.
US EPA (IRIS 2012)  SF = 7.3 (mg/kg/day)-1                    Oral SF (last reviewed in 1994) derived on the basis of the same study considered by CCME (above) where a range of slope factors was derived (4.5 to 11.7 (mg/kg/day)-1). The geometric mean was adopted as the recommended slope factor for derivation of a drinking water guideline. No assessment of inhalation toxicity is available.

There is a wide range of non-threshold reference values available for oral intakes of BaP. The most recent review, where the methodology used for low dose extrapolation was reviewed, was conducted by MfE (2011). The evaluation presented considered all the available and relevant studies noted in the above tables and identified an oral reference value based on the geometric mean. This value is considered appropriate for the derivation of HILs. However it is noted that the reference document remains a draft at the time of preparation of this evaluation, hence additional consideration of a finalised peer-reviewed reference value has also been presented.

Based on the available published peer-reviewed sources, the oral reference value presented in the WHO DWG (2011) can also be considered (remains current and relevant) in the derivation of soil HILs. The WHO oral reference value is similar to the value derived by RIVM (2001) and has been adopted by EA (2002).

The data available on inhalation exposures is dominated by occupational studies associated with exposure to coke oven emissions or coal tar pitch aerosols. BaP is not volatile and hence the relevance of these studies to the assessment of dust issues derived from contaminated sites is not clear. It is therefore