After more than a decade of research and collaboration, the updated Australian and New Zealand PFOS freshwater Default Guideline Values (DGVs) have been released. These values represent a major advance in protecting aquatic ecosystems while also underscoring an important remaining challenge: bioaccumulation risk to wildlife.
Updated PFOS freshwater DGVs (µg/L):
- 0.02 – 99% species protection
- 0.9 – 95%
- 4 – 90%
- 20 – 80%
As DGVs do not account for bioaccumulation, the 99% protection level is recommended for most slightly to moderately disturbed systems.
What’s new?
An interim screening threshold of 0.0005 µg/L (Vardy et al., 2025) has been proposed to help assess risks to birds and mammals consuming aquatic fauna.
Emerging evidence shows PFOS can accumulate through food webs to levels that may pose risks to wildlife when water concentrations are below guideline values.
What this means in practice:
- Exceed DGVs → consider further investigation
- Exceed screening threshold → consider wildlife risk assessment
As always, site‑specific assessment is critical, drawing on multiple lines of evidence from contaminant sources and exposure pathways to receptor ecology and biota sampling.
References
- Perfluorooctane sulfonate (PFOS) in freshwater: toxicant default guideline values for protecting aquatic ecosystems
- PFAS National Environmental Management Plan 3.0 – DCCEEW
- Vardy et al. (2025). Current water quality guidelines may not protect wildlife from PFOS bioaccumulation in freshwater ecosystems. Integrated Environmental Assessment and Management
Kirsten Broadgate
IBERA‑certified Environmental Risk Assessor | Principal, ERIAS | Co‑author, PFOS freshwater DGVs
kirsten.broadgate@eriasgroup.com
Kirsten Broadgate | LinkedIn