Human Health & Ecological Risk Assessment




Greencap is now part of WSP

WSP Contaminated Land and Soil Remediation


Greencap offers specialist services in Human Health Risk Assessment (HHRA) and Ecological Risk Assessment (ERA). Risk Assessments assess the potential impact of a contaminant or hazard on human health or the environment. Risk Assessments are often undertaken as part of a Contaminated Site Assessment, to assess whether contamination at a site in air, soil, soil vapour, surface water or groundwater is likely to pose a risk to human health (for example construction workers, residents, school children or workers in an occupational setting) ot the environment.

Risks can be generated from human activities, such as current or historical industrial operations, mining or waste management practices, or may be related to naturally occuring substances. HHRA considers these potential risks to human health from exposure to chemicals and hazardous materials, such as heavy metals, hydrocarbons, solvents and asbestos in the environment. The risks can be assessed for residents on a contaminated site, children in a school or playground, workers in an occupational setting, or other community groups.

Ecological Risk Assessment considers ecosystem risks if they are relevant to the type of environment and land use or proposed development.

The outcomes of a HHRA or an ERA can often inform the extent of site remediation works that need to be carried out o make a site safe to occupy or redevelop, or to minimise the risks that are being posed to the environment.


The Tiered Approach to Risk Assessment on Contaminated Sites

Greencap uses a tiered approach to HHRA and ERA, in line with the National Environmental Protection Measure (NEPM) guidance. 

A screening level assessment is the first stage (Tier 1), where known site data is compared to published health or ecological risk-based guidance levels, such as the Health Investigation Levels or Ecological Investigation Levels.

If known site data exceeds the risk-based guidance levels, a Tier 2 HHRA or ERA can be undertaken, using conservative assumptions about the site, the receptors and the expected exposures. If a Tier 2 Risk Assessment estimates there is low risk to health or the local ecology from the contaminants, then there is no need to continue to the next tier.

Most sites only require a Tier 1 or Tier 2 assessment.


Risk Assessments and Expert Witness Work Not Related to Site Contamination

Greencap also completes Risk Assessments and provides Expert Witness capability on a range of exposure risk scenarios not related to contaminated sites. These scenarios can vary enormously, with examples of this type of offer including:

  • Use of trated timber in schools
  • Health impacts of compost use
  • Asbestos risks in soil or buildings
  • The risks posed by the use of Lead Paint
  • Assessment of pathogenic risks



The two primary outcomes of a HHRA or ERA are:

  • Advice about the level of potential health risk on the site and whether the site is suitable for the use
  • Development of site-specific clean-up criteria, or Site-Specific Target Levels (SSTLs) or Trigger Levels that can be included in an Environmental Monitoring Plan

A risk assessment report can provide information to support a site owner, auditor or regulator to decide on a site’s suitability for use or development, even if some contamination is present. Risk assessments can also help minimise the amount of clean-up or controls needed to manage potential risks and reduce the time and costs for regulatory compliance.


Australian Guidance Documents

Greencap risk assessment services are guided by the primary national guidelines for risk assessment including:  


Contact Our Experts

Dylan Burford

Planning & Approvals Team Executive SA/WA

Greencap acknowledges the Traditional Owners of Country throughout Australia and recognises their continuing connection to land, waters and culture.  We pay our respects to their Elders past, present and emerging.