Common Instructions
These are the terms and instructions clients, councils and legal teams commonly use for this work in Australian practice.
- Detailed Site Investigation
- DSI
- Detailed site investigations
- Phase 2 ESA Australia
Reviewer
Reviewed by Michael Nicholls, Principal Environmental Scientist (CEnvP #0831, Site Contamination Specialist SC40037).
Last reviewed 23 April 2026.
Primary Sources
These official references commonly inform the way this work is scoped, interpreted or defended.
Detailed site investigations for higher-consequence contamination decisions.
Where a site requires intrusive investigation, targeted laboratory analysis and defensible interpretation, iEnvi delivers detailed site investigations that help clients move from uncertainty to an evidence-based position.
Typical matters
- Sites where a PSI indicates contamination is possible or likely.
- Auditor, lender, regulator or transaction requirements for more defensible evidence.
- Projects that need delineation before remediation, design or land use decisions progress.
Scope of advice
- Sampling design, intrusive investigation and laboratory testing.
- Conceptual site model refinement, risk interpretation and contaminant delineation.
- Reporting that supports remediation scoping, approvals, auditors and other stakeholders.
How we work
- Scope shaped around the actual decision, not simply maximum sampling.
- Clear interpretation of what the data does and does not establish.
- Strong contaminated land, remediation and project-facing judgement.
Selected project summaries.
These published project summaries provide practical examples of adjacent site issues and service delivery.
Preliminary Site Investigations for Potential Acquisition, VIC and WA
Two coatings manufacturing sites in Victoria and Western Australia were assessed by iEnvi through preliminary site investigations (PSI) to identify contamination risks, regulatory implications…
Metropolitan Bus Depots – Environmental Compliance and Investigations
Practical environmental investigations and compliance audits across four Melbourne bus depots established a defensible baseline, identified localised hydrocarbon impacts near refuelling areas, confirmed no…
Ensuring Safe School Development: Soil and Asbestos Investigations in Wollert
iEnvi conducted a Preliminary Site Investigation and soil testing across two lots (≈9.9 ha) in Wollert, Victoria. Eleven surface samples and stockpile checks found…
Further reading and related service pages.
Need advice on this issue?
Contact iEnvi on 13000 43 684 or email hello@ienvi.com.au to discuss the site, timing and available information.
Common Questions
What does a Detailed Site Investigation involve?
A DSI involves physical sampling of soil and/or groundwater at targeted locations across the site. This typically includes drilling boreholes or test pits, collecting samples at specific depths, installing groundwater monitoring wells where needed, and laboratory analysis for contaminants of concern identified in the PSI. The results are compared against relevant investigation and screening levels, and the report provides a risk-based interpretation and recommended next steps.
How many samples are needed for a DSI?
The number of samples depends on the site size, the conceptual site model, the contaminants of concern, and the applicable guidelines (such as NEPM 2013 in Australia). A small residential site might require 5–10 soil samples and 2–3 groundwater samples. A larger industrial site could require 30+ soil samples across multiple depth intervals. We design the sampling programme to be statistically defensible and fit-for-purpose, not over-engineered.
How long does a DSI take?
Field work for a standard DSI can usually be completed in 1–3 days. Laboratory turnaround is typically 2–3 weeks for standard analytes, or faster with express turnaround at additional cost. The full report is usually delivered within 3–5 weeks of site access. Complex sites with multiple phases, groundwater installation, or PFAS may take longer. We confirm the programme and timeline at proposal stage.