In Australia, the normal approach for triggering further investigation during contaminated land investigations is to determine whether the concentration of contaminants of concern in soil and/or groundwater exceed published health investigation levels (HILs) or ecological investigation levels (EILs). These levels may also form the basis for clean-up criteria. In the case of petroleum hydrocarbons, a number of HILs exist; however, these are limited and do not extend to a variety of soil types and aquifer situations, or to the assessment of volatile hydrocarbons.

The Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE) has undertaken the development of health-based screening levels (HSLs) for petroleum hydrocarbons to address an identified need for consistent human health risk assessment of petroleum hydrocarbon contamination in Australian conditions. The HSLs represent the best collective view of the available science and application of Australian approaches on selection of health criteria and exposure parameters.

The development of the HSLs was conducted through detailed consultation with the Australian health and environmental regulators, laboratories, research groups, oil industry and environmental consultants.

The package of work has now been completed and released for the Australian remediation industry.  The HSLs and the underlying methodology may now be used for health risk assessment purposes in the context of the wider site assessment framework for petroleum hydrocarbon contamination provided in the Assessment of Site Contamination NEPM as varied.

To support the uptake and appropriate application of the HSLs, this full-day workshop will provide instructions and case study examples on how the HSLs should be applied in practice and details on the key limitations of their use. The workshop will also guide attendees through the development of the HSLs and guidance documents, to provide a better understanding of their basis and insight into the decisions made during the consultation process.

The tentative outline of the workshop is as follows, and runs from 8.30am - 5pm (to be presented by Eric Friebel, Senior Engineer – Environmental Risk Assessment at GHD):

Session 1 (1.5hrs)

• Introduction  
• The HSL Package – What it contains
• Consultation process, role of the Project Advisory Group and international peer review 
• Project history
• Initial literature study and key study points
• TPH speciation and fraction selection
• Vapour model review and selection
• Conceptual site model (scenario selection and exposure pathways)
• Technical document walkthrough – Key assumptions

 Break

 Session 2 (1.5hrs)

• Technical document walkthrough (cont.)
• Comparison with international criteria
• Sensitivity assessment
• Vapour degradation
• Application document walkthrough
• Key limitations
• Soil texture selection
• Sources and depths

 Break

 Session 3 (1.5hrs)

• Application document walk through (cont.)
• Variations of receptor groups
• Selecting HSL
• Applying adjustments to HSLs
• Exceptions (e.g. rock lithology)
• Significant issues identified during reviews

Break

Session 4 (1.5hrs)

• Case studies and worked through examples
• Closing summary and discussion