ANZG 2026 Finalises Major Revisions to PFOS Freshwater DGVs

ANZG 2026 finalises revised PFOS freshwater guideline values and introduces new biota screening threshold

Overview

The Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZG) framework has undergone its most consequential revision to PFOS criteria in over a decade. In May 2026, following a technical brief published in March 2026, the Australian and New Zealand Governments officially published finalised Toxicant Default Guideline Values (DGVs) for perfluorooctane sulfonate (PFOS) in freshwater. The revision follows an independent scientific review that excluded a 2012 toxicity study previously relied upon to derive the older criteria under NEMP 2.0, resulting in upward revisions to all four protection levels. State EPAs across Australia have referenced these values within their regulatory frameworks, meaning the new thresholds function as operative benchmarks for assessment and compliance purposes.

For environmental practitioners working on contaminated land, PFAS investigation, surface water monitoring, and ecological risk assessment, this update represents a genuine structural change rather than an incremental adjustment. The nearly 100-fold relaxation of the 99% species protection DGV from 0.00023 µg/L to 0.02 µg/L will alter compliance outcomes for a large number of active projects. Sites that previously appeared to be in exceedance of surface water criteria may now fall within acceptable limits under direct toxicity assessment. However, the update simultaneously introduces a new and demanding biota screening threshold of 0.0005 µg/L, which decouples the bioaccumulation pathway from the DGVs entirely and shifts the analytical and assessment burden toward the aquatic food web.

The update is better understood as a restructuring of how ecological risk from PFOS is conceptualised and assessed in Australian waterways, rather than a straightforward relaxation of surface water criteria. Practitioners who read this update only as a relaxation of surface water criteria are reading it incompletely. The introduction of the biota screening threshold creates a new and distinct assessment trigger that requires ultra-trace analytical capability, additional field sampling, and integration with PFAS NEMP 3.0 biota guideline values. Developers, councils, lawyers managing environmental liabilities, and site owners with PFAS-affected surface water on or near their land all need to understand both sides of this regulatory change.

Key details of the ANZG 2026 PFOS freshwater default guideline values

The finalised ANZG 2026 PFOS freshwater DGVs across all four species protection levels are as follows. The 99% species protection level is now set at 0.02 µg/L, revised upward from 0.00023 µg/L under NEMP 2.0. The 95% species protection level is now 0.9 µg/L, revised from 0.13 µg/L. The 90% species protection level is set at 4 µg/L, and the 80% species protection level is set at 20 µg/L. The 90% and 80% values are newly published at these levels and represent the lower protection tiers used for moderately and substantially disturbed ecosystems respectively, as defined under the ANZG ecosystem condition framework.

The upward revision across all protection levels is a direct consequence of the independent scientific review process that identified and excluded a 2012 toxicity study which had disproportionately influenced the derivation of the older, more conservative DGVs. The exclusion of that study altered the species sensitivity distribution underlying the criteria, producing a dataset that reflects a broader and more current evidence base. The revised DGVs are therefore considered more scientifically defensible, not simply more permissive. It is important for practitioners to understand this distinction when communicating with regulators, clients, and in reporting, because the scientific basis for the new values is stronger than for those they replace.

A critical methodological change in ANZG 2026 is the deliberate decoupling of direct aquatic toxicity from bioaccumulation effects within the surface water DGVs. The previous DGVs incorporated a bioaccumulation factor intended to protect predators higher in the food chain, including mammals and birds, from dietary exposure via contaminated fish and invertebrates. The new DGVs do not include this factor. Instead, the ANZG 2026 update introduces a standalone biota screening threshold of 0.0005 µg/L for PFOS in surface water. This threshold functions as a trigger point rather than a compliance limit in the traditional sense. If measured PFOS concentrations in surface water exceed 0.0005 µg/L, the practitioner is required to proceed to direct tissue sampling of aquatic biota and to assess compliance against the PFAS NEMP 3.0 biota guideline values, which govern risks to mammalian and avian predators through the food web pathway.

The practical consequence of the 0.0005 µg/L biota screening threshold is an immediate and non-negotiable analytical challenge. Standard laboratory reporting limits for PFOS in water commonly sit at or above this level, depending on the method and the matrix. The ISO 21675 and US EPA Method 533 analytical frameworks can achieve lower reporting limits under optimised conditions, but these capabilities are not uniformly available from all commercial laboratories operating in Australia. If a laboratory cannot achieve a Limit of Reporting (LOR) below 0.0005 µg/L, it cannot provide a result that reliably rules out the need for biota sampling. A result reported as less than 0.001 µg/L, for example, straddles the screening threshold and leaves the assessment incomplete. Practitioners must verify LOR capability with their laboratory before sampling commences, not after results are received.

Australian context: how the ANZG 2026 PFOS update intersects with state EPA frameworks and PFAS NEMP 3.0

Australia’s regulatory approach to PFAS in the environment operates through a layered system. At the national level, the PFAS National Environmental Management Plan (NEMP) establishes investigation levels, guideline values, and assessment frameworks that state and territory regulators draw upon when setting their own requirements. The ANZG 2026 update sits within this broader architecture. The revised PFOS freshwater DGVs are intended to operate alongside the PFAS NEMP 3.0 biota guideline values rather than replace them. Where the DGVs govern direct toxicity to aquatic organisms, the NEMP 3.0 biota values address the food web pathway to birds and mammals. The biota screening threshold of 0.0005 µg/L is the operational link between these two frameworks. A surface water result that exceeds this threshold does not itself indicate a regulatory breach, but it does trigger the obligation to assess the biota pathway, bringing NEMP 3.0 values directly into the assessment. Practitioners operating across jurisdictions should confirm how their relevant state EPA has incorporated or referenced the ANZG 2026 values within its current guidance, as implementation timelines and any jurisdictional modifications may vary.

References and related sources

• Primary source: www.waterquality.gov.au
• PFAS National Environmental Management Plan (NEMP)
• ANZG Water Quality Guidelines

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This is an iEnvi Machete news summary. Prepared by iEnvi to summarise the source article for contaminated land, groundwater, remediation, approvals and site risk professionals.

Published: 06 May 2026

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