Contaminated-site work should follow a conceptual site model: understand sources, pathways and receptors; investigate with a data-quality objective; assess risk; select a feasible remedy; and verify that agreed closure criteria are met.
Investigation should reduce decision uncertainty. More samples are not automatically better if they do not test the conceptual model.
Who should use this guide?
Industrial owners, property developers, investors, lenders and operators managing legacy contamination or site closure.
A practical implementation sequence
- Compile site history and an initial conceptual site model.
- Define investigation questions, sampling design and quality controls.
- Refine source, pathway and receptor understanding from results.
- Set risk-based objectives and compare feasible remedies.
- Implement, monitor and verify closure or long-term controls.
Data and evidence required
The conclusion becomes more reliable when boundaries, data sources, responsibilities and quality checks are documented from the start.
- Historical operations, spills and storage records
- Borehole, soil, groundwater and laboratory data
- Survey and utility information
- Risk assumptions and remedy evaluation
- Waste records, validation samples and monitoring results
Common mistakes to avoid
- Sampling before defining the decision question
- Ignoring groundwater or preferential pathways
- Selecting a remedy on cost alone
- Declaring closure without validation and residual-risk controls
Checklist before sign-off
- Conceptual model explains all material findings
- Data quality matches the intended decision
- Uncertainty and data gaps are explicit
- Remedy addresses source, pathway and receptor
- Closure evidence and future obligations are documented
This checklist does not replace project-specific legal or contractual advice. Confirm the applicable framework for every assignment.