Introduction
In today’s environmental and construction landscape, the need for robust groundwater monitoring has never been greater. The presence of Per‑ and Polyfluoroalkyl Substances (PFAS) in groundwater is reshaping how we understand contamination pathways, design monitoring networks and meet Environment Protection Authority (EPA) standards. At Nova Group Pacific we support property developers, construction companies, industrial operators and government bodies to navigate this evolving terrain confidently.
In this article we will:
- Explore PFAS migration and its implications for groundwater monitoring
- Discuss how to design efficient monitoring networks tailored for PFAS and emerging contaminants
- Outline what EPA reporting expectations mean for your project in Australia
Understanding PFAS Migration in Groundwater
Why PFAS matter for groundwater
PFAS, often referred to as "forever chemicals", are synthetic compounds that resist degradation and can migrate through soil into groundwater. They are found in a variety of legacy uses: fire-fighting foams at airports and defence sites, manufacturing processes, chemical spills and landfills. The national guidance, the PFAS National Environmental Management Plan 3.0 (PFAS NEMP 3.0), provides a consistent frame for managing PFAS in the environment.
Key migration behaviours include:
- Subsurface flow of PFAS dissolved or sorbed in groundwater and in soil pore-water
- Vertical migration, particularly where preferential pathways (e.g., boreholes, cracked aquitards) exist
- Lateral spreading from point sources, but also diffuse migration from broader urban/industrial catchments
- Long-term persistence and “tailing” behaviour — even where source control is applied, concentrations diminish slowly
A recent Australian groundwater study highlighted the challenge of legacy PFAS migration from landfill and industrial sites, showing detectable concentrations and complex hydrochemical interactions.
Read more in our article Climate Change Effects on Local Water Assessments
Key implications for our industry
For property developers, construction companies, industrial operators and local councils, the migration behaviour of PFAS demands a re-thinking of groundwater monitoring. Traditional contaminant models (heavy metals, hydrocarbons) may not fully address PFAS behaviour. Practical implications include:
- Monitoring wells must consider deeper/smaller contaminant plumes and longer-term persistence
- Risk assessments must incorporate aquifer connectivity, potential off-site migration and exposure pathways (e.g., groundwater supply, dewatering, off-site receptors)
- Early engagement in the concept and design of monitoring programs can significantly de-risk development and remediation timelines
For detailed assessment services, see our Groundwater and Surface Water capability.
Designing Efficient Monitoring Networks for PFAS Groundwater
Setting the strategic framework
When designing a monitoring network for PFAS-impacted groundwater in Australia, we recommend taking a structured step-wise approach:
- Source characterisation – Identify likely PFAS sources (fire-fighting foam training areas, industrial processes, landfills, on-site chemical uses).
- Conceptual Site Model (CSM) – Map contamination sources, pathways (soil–groundwater interface, preferential conduits), receptors (groundwater bores, dewatering points, surface water bodies) and conceptual migration zones.
- Monitoring objectives – Define clear aims: e.g., early detection of plume migration; dewatering compliance; post-remediation validation; receptor assurance.
- Well/point selection – Place sentinel wells at likely migration pathways, receptor zones and along hydraulic gradients. For PFAS this frequently means:
- Up-gradient background wells (baseline or ambient PFAS levels)
- Down-gradient “pathway” wells between source and receptor
- Receptor wells near groundwater supplies, dewatering discharge outlets or surface water bodies
- Up-gradient background wells (baseline or ambient PFAS levels)
- Sampling and analytical methods – Ensure selected laboratories are proficient in ultra-trace PFAS analysis, with appropriate QA/QC and detection limits.
- Frequency and triggers – Determine monitoring intervals and trigger values (for example, comparison to guideline values or site-specific response levels).
- Reporting and response framework – Build in clear response pathways if PFAS exceed thresholds: further investigation, expanded network, remediation linkage.
Practical design considerations
- Multi-level monitoring: For aquifers with vertical stratification, multi-level wells provide better resolution of PFAS migration at different depths – this prevents missing vertical migration that a single well screen may not detect.
- Well integrity and hydraulics: Bore integrity, annular seal, well screen placement and sampling methodology are critical to avoid cross-contamination or artefacts given the very low concentrations relevant for PFAS.
- Baseline/ambient levels: Many areas (especially urban/industrial) show low-level PFAS detection. For example, in Western Australia an ambient groundwater investigation found PFAS in 91 % of sampling locations. Establishing site-specific baseline is essential for interpreting detected levels.
- Trigger-response plan: A practical monitoring network must embed a Trigger and Response Plan (TARP), defining when escalation or remediation action is required. The example from a mining ground water PFAS plan in WA describes a four-level monitoring trigger system.
- Integration with soil and surface water: PFAS erodes the boundaries between groundwater, soil and surface water monitoring. Your program may need to include soil pore-water, surface water discharge, and groundwater in a holistic monitoring strategy.
Outcomes we aim to deliver
By utilising well-designed monitoring networks, we help our clients achieve:
- Early detection of PFAS migration and reduced risk of unnoticed plume growth
- Compliance with modern regulatory expectations (including PFAS NEMP) and improved audit readiness
- Quantification of exposure risk to receptors (e.g., groundwater supply bores, dewatering discharges)
- Support for remediation design, dewatering management, redevelopment planning and liability management
For groundwater and surface water assessment services refer to our Groundwater & Surface Water Assessments capability.
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