Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:2:p8
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 2 (pt 8/21)
Character Range: 60377–63381

it is used to calculate one of the many input parameters (advective air flow) in the Johnson & Ettinger model. For further information refer to section 7.3.2 of Friebel and Nadebaum (2011a).

As for other input parameters, the selected value for the attenuation factor is based on a reasonable assumption rather than the maximum possible exposure and is equivalent to the median of the US EPA 2008 attenuation factor database (US EPA 2008) and lies within the 75th to 95th percentiles of the updated database published in 2012 (US EPA 2012). The selected value of 0.005 was considered to represent the upper value not affected by indoor air sources, background air or other confounding factors.

    2.4.4          Petroleum fuel composition
The soil saturation and water solubility limits used in the derivation of the HSLs assume a fixed fuel composition based on fresh petrol and diesel fuels typical of those available in Australia. The HSLs may be applied to other fuel types (e.g. kerosene, aviation fuel and fuel oil) providing that the aliphatic/aromatic speciation is similar to that assumed in the derivation of the HSLs (80:20). Further information on these fuel types can be found in TPHCWG (1998). There are a number of fuel additives, such as MTBE and ethanol, for which HSLs have not been derived. Where these are identified as potential contaminants of concern, then a site-specific risk assessment for these chemicals should be considered.

The HSLs apply to petroleum contamination sources and are not applicable to pure compound solvents, as solubility limits incorporated into the HSLs were derived based on typical petrol and diesel fuel mixtures. Equivalent values to the HSLs applicable to pure compounds (rather than fuel mixtures) are available in Friebel and Nadebaum (2011a Appendix C).

    2.4.5          The Total Recoverable Hydrocarbons analytical method
The Total Recoverable Hydrocarbons (TRH) method is recommended for the analysis of petroleum hydrocarbon compounds in soil. Detailed information is provided in Schedule B3.

The term TRH is equivalent to the previously used total petroleum hydrocarbons (TPH) and represents extracted biogenic (biological) and petrogenic (petroleum) hydrocarbons by selected solvents. The TRH analysis is non-specific and will extract organic compounds such as ethanol, biodiesel compounds (esterised long chain fatty acids), organic acids, sterols and n-alkanes from plant waxes, as well as petroleum hydrocarbons. The sample extraction process may also extract other industrial organic chemicals. When used in the context of a screening assessment for petroleum hydrocarbon contamination, TRH analyses are likely to be conservative when non-petroleum compounds are present.

The potential for inclusion of non-petroleum compounds in the results may be relevant for site-specific assessment of petroleum hydrocarbon contamination. For example, the TRH analytical results may be overly conservative if soil organic matter is unusually