New national rules for assessing site contamination are now in force which will change how site investigations are undertaken and human health and ecological risks are assessed for particular contaminants.

The National Environment Protection (Assessment of Site Contamination) Measure (NEPM) was originally made in 1999 and was subject to a five year review process. The NEPM is the primary national guidance document used by consultants, site auditors, regulators and industry generally to investigate and determine the risks posed by contaminated land.

The NEPM is made up of two Schedules. Schedule A contains a flowchart outlining the recommended general process for the assessment and management of site contamination. Schedule B comprises ten technical guidelines about site assessment criteria, investigation procedures, laboratory analyses, human health risk assessment, ecological risk assessment, groundwater assessment, community consultation, competencies and acceptance of consultants and auditors and workers health and safety.

The NEPM review process has taken 8 years partly because of delays within Government and partly because the content of the supporting technical guidelines needed to be resolved. The revised NEPM was registered by the Ministerial standing Counsel on Environment and Water on 15 May 2013 with the existing NEPM being repealed on 17 May 2013.

Key changes

The NEPM now includes express acknowledgements that:

  • local and state government involved in the planning and development process for contaminated sites need to ensure that the site will be suitable for its intended use;
  • industries, including mining and mineral processing industries, need to ensure appropriate measures are taken during equipment and site decommissioning to leave the site in a safe and stable condition in order to prevent or, so far as is practicable, minimise adverse long-term environmental (physical, social and economic) impacts;
  • community engagement should start at an early stage (and continue throughout) the site contamination assessment process where the community could reasonably be expected to have an interest;
  • site contamination assessment needs to consider risks to water resources as well as other ecological risks;
  • initial assessment of human health and ecological risks may be done by comparing the contamination levels to screening or investigation level criteria, or if necessary, a site specific risk assessment;
  • the sustainability of the management strategy needs to be assessed in order to achieve an appropriate balance between the benefits and effects; and
  • specialised forms of assessment are required for particular contamination types including unexploded ordnance, radioactive substances and contaminated sediments.

The key changes, however, are in the detail and relate to the new content of the technical guidelines which cover:

  • investigation levels for soil and groundwater;
  • site characterisation;
  • laboratory analysis of potentially contaminated soils;
  • site-specific health risk assessment methodology;
  • ecological risk assessment;
  • methodology to derive ecological investigation levels in contaminated soils;
  • ecological investigation levels for arsenic, chromium (III), copper, DDT, lead, naphthalene, nickel and zinc;
  • framework for the risk based assessment of groundwater contamination;
  • derivation of health investigation levels;
  • community engagement and risk communication; and
  • competencies and acceptance of environmental auditors and related professionals.

One of the most significant changes from a site investigation perspective has been the inclusion of specific guidance (based on guidance developed by the Western Australian Department of Health) on how to assess asbestos contamination in soil and health screening levels for asbestos which adopt a more conservative approach than the Netherlands to take account of Australia's greater dryness and potential for dust generation.

Implications

The Decision Regulatory Impact Statement (DRIS) prepared in support of the amendments estimates that the application of the updated NEPM could result in an increase in site assessment costs of up to 10-15%. However, the DRIS analysis indicates that potential cost savings at the remediation and management stage will reduce the overall direct cost to industry and regulators, as well as providing great social justice and equity for the community.

The NEPM changes to the site investigation levels for soil and groundwater contamination together with the guidance on ecological investigation levels and ecological and human health risk assessment mean that going forward some sites (depending on the contamination) will be subject to further investigation and possibly remediation while other sites will not require any remediation. Landowners, industry and developers will need to bear this in mind when they are considering divestments, decommissioning or development activities.