Heavy Metals
Summary
Heavy metals are metallic elements that occur naturally in the environment and, at elevated concentrations, can pose risks to human health and the environment. In contaminated land and environmental assessments, heavy metals are commonly assessed in soil, groundwater, sediment and waste materials.
Heavy metals are frequently encountered at sites with a history of industrial activity, waste disposal, fuel storage, mining or fill placement and are a key consideration in development and remediation projects.
Definition
Heavy metals are elements such as lead, arsenic, cadmium, mercury, chromium, copper, nickel and zinc that have relatively high atomic weight and density. While some metals occur naturally in soil at background levels, contamination refers to concentrations elevated above natural background or guideline values due to human activities.
Assessment of heavy metals typically involves laboratory analysis and comparison against relevant criteria based on land use and exposure pathways.
Why Heavy Metals Matter
From a health perspective, exposure to elevated concentrations of heavy metals can occur through direct contact with soil, ingestion of dust, inhalation of particulates or migration into groundwater. Some metals are toxic even at low concentrations and may cause acute or chronic health effects.
From an environmental perspective, heavy metals can persist in soil and groundwater and may migrate beyond the source area, affecting ecosystems and downstream environments.
Heavy metals are also a regulatory consideration. Their presence can trigger requirements for further investigation, risk assessment, remediation or waste classification. Failure to appropriately assess heavy metals can lead to delays in approvals or unexpected remediation costs.
Common Sources of Heavy Metal Contamination
Heavy metal contamination may arise from:
Industrial and manufacturing activities
Fuel storage and service stations
Mining and extractive industries
Waste disposal or landfilling
Use of contaminated fill materials
Agricultural and chemical use
Historical demolition or construction practices
Understanding site history is critical to identifying potential heavy metal risks.
When Heavy Metals Are Typically Assessed
Assessment of heavy metals is commonly required where:
A Preliminary or Detailed Site Investigation is undertaken
Development or rezoning is proposed on land with a history of industrial use
Soil or groundwater contamination is suspected
Waste classification is required for excavated material
Validation is required following remediation
The scope of assessment is typically aligned with site conditions and proposed land use.
Legislative and Regulatory Context
Heavy metals are assessed under contaminated land and environmental protection frameworks.
In New South Wales, heavy metal concentrations are commonly assessed against relevant EPA guidance and industry criteria as part of contaminated land investigations and waste classification. Similar regulatory expectations apply across Australia.
Regulators expect assessments to consider both total concentrations and relevant exposure pathways.
How We Can Help
Confluence Environmental assesses heavy metals as part of contaminated land, waste classification and remediation projects.
Our services typically include:
Targeted sampling and laboratory analysis
Interpretation of results against applicable criteria
Risk-based assessment of potential exposure pathways
Advice on remediation, management or disposal requirements
Clear reporting to support planning and regulatory review
We focus on providing practical, defensible assessments aligned with project objectives.
Related Terms and Concepts
Contaminated Land
Preliminary Site Investigation
Detailed Site Investigation
Waste Classification
Hazardous Waste
Remediation Action Plan
Site Validation