Assessment & remediation
The assessment and remediation of site contamination incorporates a number of strategies and methods to first determine the nature and extent of chemical substances existing on or off site. Following this determination, the actual or potential risk to human health or the environment is determined. If there is a risk, remediation will required to treat, contain, remove or manage the chemical substances on or below the surface of the site
Site contamination assessment may be undertaken in a number of stages with objectives being to understand and characterise the chemical substances including:
- source of contamination
- nature of contamination, including what chemical substances pose a risk at the site.
- The extent of the contamination and what is impacted (eg soil, groundwater, surface water, soil vapor)
- potential risk posed to human health or the environment as a result.
Assessing and remediating site contamination
Remediation is the treatment, containment, removal or management of chemical substances so that they no longer represent actual or potential harm to human health or the environment. It takes into account the current or intended land use and contemplates actual or potential harm to water that is not trivial.
Remediation may involve activities on or off site, and often requires treatment or disposal of impacted materials. Several methods may be used concurrently, especially where remediation of contaminated groundwater is required.
Poorly managed remediation may result in adverse impacts on human health, property and the environment.
Methods and processes used in remediation can range from relatively straightforward earthmoving operations to complex technological treatment processes. They may result in adverse impacts on the environment and adjoining land occupiers if not properly managed.
A national approach to the remediation of sites in Australia has been developed through the Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE). The National Remediation Framework provides practical guidance to consultants, auditors, practitioners and regulators.
The Guidelines for the assessment and remediation of site contamination provides a framework for undertaking remediation and explains the expectations of the EPA for those who undertake remediation.
The guidelines describe in detail the environmental aspects that must be considered, and planned for, before starting a remediation project. It is anticipated that careful planning prior to remediation will result in the control of both predictable and preventable environmental impacts.
Certain types of remediation may also require development approval and an authorisation (or licence) from the EPA.
When should the assessment of site contamination be undertaken?
The assessment of site contamination should be undertaken whenever contamination has been identified at a site, or when there is a reasonable suspicion of site contamination arising from a current or previous activity or use of the site.
This provides a 'trigger' to initiate the recommended processes for assessment outlined in Schedule A of the National Environment Protection (Assessment of Site Contamination) Measure (ASC NEPM).
Use of these triggers and following the assessment process should ensure that there is adequate protection of human health and the environment wherever site contamination has occurred.
Who can undertake the assessment of site contamination?
Site contamination assessment is a complex and specialised profession and should only be undertaken by professionals with a range of competencies, qualifications and experience.A site contamination consultant is specifically defined in the Environment Protection Act 1993 (EP Act) as a person who assesses the existence or nature or extent of site contamination.
A certified practitioner is a person who has been assessed by an EPA recognised certification body as being suitably qualified and experienced professional. The EPA requires or recommends the use of a certified practitioner as described in its Certification of practitioners policy.
In some situations, an audit of the work undertaken by the certified practitioner may be required. An auditor is an expert professional accredited by the EPA to undertake an independent review of assessment and/or remediation work carried out by consultants. The triggers for a site contamination audit are described in the Guidelines for the site contamination audit system
A list of persons accredited by the EPA as site contamination auditors can be viewed on the auditor register.
What is a 'sensitive use'?
A 'sensitive use', in relation to site contamination, means one involving a residential use (including all forms of residential use such as medium and high density developments and retirement villages), a pre-school (including a childcare centre) or a primary school.
The ASC NEPM provides a national risk-based framework for the staged or tiered assessment of site contamination in Australia. The assessment of site contamination in Australia should be undertaken in accordance with the ASC NEPM.
The EPA has published several guidelines and information sheets to inform the assessment and remediation of site contamination:
- Guidelines for the assessment and remediation of site contamination
- Guidelines for the assessment of background concentrations
- Regulatory and orphan site management framework
- Regulation of site contamination.
If you have any questions please contact the Site Contamination Branch on (08) 8204 9934.