Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:2:p4
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 2 (pt 4/5)
Character Range: 2774639–2779615

in 2007) derived on the basis of a NOAEL (HEC) of 1553 mg/m3 associated with liver effects in mice and rats, and an uncertainty factor of 100.

In relation to inhalation exposures (the only pathway considered in development of soil vapour Interim HILs) the most recent review conducted by US EPA (which is consistent with the older review from RIVM) has been adopted.

    2.5.3         Recommendation
In relation to 1,1,1-TCA, only soil vapour Interim HILs have been derived. Hence only the inhalation pathway has been quantified in the development of these HILs. On the basis of the discussion above, the following inhalation toxicity reference values (TRVs) have been adopted for 1,1,1-TCA:

2.6              Calculated Interim HILs
On the basis of the above, the following interim soil vapour HILs have been derived for 1,1,1-TCA (refer to Appendix B for equations used to calculate the HILs and Appendix C for calculations):
HIL Scenario                                                                                                                                                                                                                                                                                                                                                                               Interim Soil Vapour HIL# (mg/m3)
Residential A                                                                                                                                                                                                                                                                                                                                                                              60
Residential B                                                                                                                                                                                                                                                                                                                                                                              60
Recreational C                                                                                                                                                                                                                                                                                                                                                                             1200
Commercial D                                                                                                                                                                                                                                                                                                                                                                               230
# Interim soil gas HILs are conservative soil gas concentrations that can be adopted for the purpose of screening sites where further investigation is required on a site-specific basis. They are based on the potential for vapour intrusion indoors using an indoor air-to-soil gas attenuation factor of 0.1 for HILs A, B and D and an outdoor attenuation factor of 0.05 for HIL C.

2.7              References
ATSDR 1997, Toxicological Profile for 1, 1, 1-trichloroethane, United States Department of Health and Human Services, Atlanta, Georgia, USA.
ATSDR 2006, Toxicological Profile for 1,1,1-Trichloroethane, July 2006, available from http://www.atsdr.cdc.gov/ToxProfiles/tp.asp?id=432&tid=76.
DEC 2003, Ambient Air Quality Research Project (1996-2001), Internal working paper no. 4, Ambient concentrations of heavy metals in NSW, Department of Environment and Conservation (NSW), 2003.
Hawas, O, Hawker, D, Chan, A, Cohen, D, Christensen, E, Golding, G & Vowles, P 2001, 'Characterisation and Identification of Sources of Volatile Organic Compounds in an Industrial Area in Brisbane', 16th Int. Clean Air Conf., Christchurch, New Zealand, 1822 August 2002, pp. 307313.
IARC 1999, Summaries & Evaluations, 1,1,1-Trichloroethane, vol. 71, (1999), pp. 881, International Agency for Research on Cancer.
NEPC 1999, Schedule B (7a), Guideline on Health-Based Investigation Levels, National Environment Protection (Assessment of Site Contamination) Measure, National Environment Protection Council, Australia.
NHMRC 2011, National water quality management strategy, Australian drinking water guidelines, National Health and Medical Research Council, Australia.
RIVM 1993, Derivation of Maximum Permissible Concentrations for Volatile Compounds in Air, National Institute of Public Health and the Environment, Bilthoven, Netherlands, Report no. 679101 010, October 1993.
US EPA (IRIS2012), data and information available from the Integrated Risk Information System, an online database, available from http://www.epa.gov/iris/.
US EPA 1995, Technical Guidance Manual, Assessing Dermal Exposure from Soil, US