Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:2:p2
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 2 (pt 2/6)
Character Range: 2403865–2407427

factor of 100 was considered.
    * Dermal absorption of phenol was considered to be 12%.
    * Oral bioavailability of phenol was considered to be 100%.
Based on intakes derived from soil (ingestion, dermal absorption and dust inhalation) an HIL of 8500 mg/kg was calculated.

2.3              Significance of Exposure Pathways

    2.3.1         Oral Bioavailability
Insufficient data is available to adequately define the bioavailability of phenol in the range of contaminated sites that may need to be considered in Australia. On this basis, a default approach of assuming 100% oral bioavailability has been adopted in the derivation of an HIL. It is noted that a site-specific assessment of bioavailability can be undertaken where required.

    2.3.2         Dermal absorption
ATSDR (2008) notes that phenol is readily absorbed through the skin, and the skin is considered the primary route of entry during occupational exposure (when considered as a product rather than in soil). Dermal absorption of phenol from soil has been shown and maximum phenol penetration was within 2 and 4 hours after application.

No compound-specific dermal absorption value is available for phenol and hence the default value of 0.1 (10%) for semi-volatile compounds available from US EPA (2004) has been adopted.

It is noted that phenol is a skin irritant and skin necrosis has been produced by contact with 1% solutions (UK EA 2009).

    2.3.3         Inhalation of Dust
Phenol is not considered sufficiently volatile to be of significance and inhalation exposures associated with particulates outdoors and indoors are expected to be of less significance than ingestion of soil. While likely to be negligible, potential inhalation exposures associated with dust have been considered in the HIL derived.

    2.3.4         Plant Uptake
Phenols occur naturally in plants and soils. Since phenol and phenolics are relatively water-soluble, they are present in the soil solution and are easily taken up by plants via root absorption and stored in different parts of the plant (CCME 1999). Although it has been shown that plants readily take up phenol, bioaccumulation does not take place, due to a high rate of respiratory decomposition of phenol to CO2. The potential for the uptake of phenol into home-grown produce has been considered in the derivation of HIL A. This has been undertaken on the basis of the equations presented in Appendix B with the following parameters and plant uptake factors estimated:
Parameter                                                                    Value              Reference/Comment
Parameters
Koc                                                                          187 (cm3/g)        RAIS (2010)
log Kow                                                                      1.46               RAIS (2010)
Diffusivity in water                                                         1.03x10-5 (cm2/s)  RAIS (2010)
Calculated Plant Uptake Factors (mg/kg produce fresh weight per mg/kg soil)
Green vegetables                                                             0.204              calculated
Root vegetables                                                              0.307              calculated
Tuber vegetables                                                             0.244              calculated
Tree fruit                                                                   0.00098            calculated

It is noted that plants can metabolise phenol readily, hence exposure through eating food derived from plants