Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:5:p4
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 5 (pt 4/18)
Character Range: 2978743–2984122

surface area                                                                                                                                                                                                        SAA or SAC                    cm2         20 000                            6100          20 000      6100                                  20 000  6100   20 000
Fraction of skin exposed                                                                                                                                                                                                 Fs                            %           31.5                              44.3          31.5        44.3                                  31.5    44.3   19
Dermal absorption factor                                                                                                                                                                                                 DAF                           %           Chemical specific values applied
Time spent indoors on site each day                                                                                                                                                                                      ETi                           hours       20                                20            20          20                                    0       0      8
Time spent outdoors on site each day                                                                                                                                                                                     ETo                           hours       4                                 4             1           1                                     2       2      1
Home-grown fraction of vegetables consumed                                                                                                                                                                               FHG                           %           10                                10            0           0                                     0       0      0
Vegetable & fruit consumption rate                                                                                                                                                                                       Cy (veg and fruit)            g/day       400                               280           -           -                                     -       -      -
Averaging time for carcinogens ('lifetime')                                                                                                                                                                              ATNT                          years       70                                70            70          70                                    70      70     70
Dust lung retention factor                                                                                                                                                                                               RF                            %           37.5                              37.5          37.5        37.5                                  37.5    37.5   37.5
   1. Soil ingestion rates for children are based on a child aged 23 years where normal hand-to-mouth activity is assumed and does not account for pica behaviour
   2. Soil ingestion rates for the HIL A scenario include the ingestion of both outdoor soil, including soil adhering to home-grown produce, and indoor dust (derived from outdoor soil tracked indoors)
   3. Soil ingestion rates for the HIL B scenario are based on the assumption that a quarter of the HIL A soil/dust ingestion occurs
   4. Soil ingestion rates for the HIL C scenario are based on the assumption that half of the HIL A soil/dust ingestion occurs, i.e. ingestion of outdoor soil only (no indoor dust)
   5. Soil ingestion rates for the HIL D scenario are based on the default soil/dust ingestion rates, corrected for an 8 hr/day daily exposure duration (50% of total waking hours)
  * A site-specific assessment of risk should be conducted where the exposure scenario differs from the assumptions adopted in the derivation of the HILs (e.g. commercial premises that run continuous 12 hour shifts)

5.3              Pathway-specific exposure assumptions
This section summarises the approach and pathway-specific assumptions adopted in the derivation of the HILs. All equations relevant to the calculation of the HILs are presented in Appendix B.

    5.3.1         Incidental ingestion of surface soil and dust
This exposure pathway includes the incidental ingestion of contaminated soil and dust during everyday activities. In addition, the direct consumption of soil adhering to home-grown fruit and vegetables in the residential HIL A exposure scenario has been reviewed. Soil and dust ingestion can be an important exposure pathway for surface soil contaminants and is particularly important in the case of non-volatile chemicals, such as metals. Young children are especially vulnerable to the ingestion of soil contaminants as they may have direct contact with soil and dust during play activities.

5.3.1.1         Incidental soil/dust ingestion rate
Based on a number of overseas tracer studies, enHealth