Australian Methodology to Derive Ecological Investigation Levels in Contaminated Soils

A research project conducted by CSIRO has developed a new methodology to derive ecological investigation levels (EILS) in contaminated soils and used the methodology to calculate EILs for eight contaminants.

Background

The assessment of contaminated sites within Australia is guided by the National Environment Protection (Assessment of Site Contamination) Measure (NEPM).

This NEPM, which was published in 1999, consists of a number of schedules. Schedule B(5) provides a framework to be used when conducting ecological risk assessments for contaminated sites. Schedule B(1) provides the environmental, groundwater and human investigation levels (EILs, GILs and HILs respectively) which if exceeded act to trigger further investigation.

The current interim ecological investigation levels ( EILs) are acknowledged as having a number of limitations. Due to these limitations the New South Wales Environmental Trust funded a project by CSIRO and New South Department of Environment and Climate Change (DECC). This project aimed:

• to develop a new methodology for deriving EILs, analogous to that of the Australian and New Zealand water quality guidelines;
• to test the proposed methodology by developing EILs for four chemicals (i.e. arsenic, zinc, naphthalene and DDT); and
• to seek national approval and adoption of the proposed methodology.

Almost concurrently, a review of the NEPM including a variation process commenced. The review and variation was conducted by a Project Team on behalf of the National Environment Protection Council (NEPC). The variation has now commenced with a recommendation relating to the methodology for deriving EILs:

”develop an agreed methodology for deriving terrestrial Ecological Investigation Levels to revise existing Ecological Investigation Levels, and derive new Ecological Investigation Levels” (NEPC, 2006b)

The EIL derivation methodology report

This report presents the methodology for deriving EILs that arose from our project. The methodology can also be used to derive contaminant limits that have other purposes such as remediation, intervention or target levels. The methodology is a considerable advance on the current system and gives more scientifically robust and ecologically relevant EILs.
The methodology was submitted to the NEPM Variation Team (the team responsible for varying the NEPM (Assessment of Site Contamination) and has been endorsed by the team. The methodology will be released as part of the revised NEPM for public consultation during 2010.

Proposed EILs report

A report used the EIL derivation methodology to derive soil quality guidelines (SQGs) (they can not be termed EILs until they are officially adopted) for arsenic, DDT, naphthalene and zinc. This report was presented to both the Environmental Trust and the NEPM Variation Team. CSIRO was subsequently employed by the National Environment Protection Council (NEPC) to derive SQGs for an additional four contaminants - these being chromium (III), copper, lead and nickel. This was submitted to the NEPM Variation Team, who have endorsed the proposed SQGs that are based on lowest orbserved effect concentration toxicity data and 30% effect concentration data. The two reports of proposed SQGs are being merged into one and this will be released as part of the revised NEPM for public consultation in 2010. This report is not currently available for release.

Funding Acknowledgment

For more information about Ecological Investigation Levels in Contaminated Soils

Contact:
Dr Michael Warne, Principal Research Scientist
Phone +61 8 8303 8533