BSI Publishes First Major Revision to Contaminated Land Investigation Standard Since 2011

BS 10175:2026: What Environmental Consultants Need to Know

The British Standards Institution published BS 10175:2026 (Investigation of potentially contaminated sites – Code of practice) on 25 March 2026, marking the first full revision of this foundational site investigation standard in fifteen years. The update is not a minor administrative refresh. It introduces substantive new guidance on sampling and assessing emerging pollutants, specifically per- and polyfluoroalkyl substances (PFAS) and microplastics and nanoplastics, and it formally integrates sustainability and climate change resilience requirements into the site investigation process itself. For a standard that underpins how environmental professionals design phased investigations, construct Conceptual Site Models (CSMs), and report findings to regulators, this is a material change to accepted international practice.

BS 10175 has long carried authority beyond the United Kingdom. Australian environmental consultants routinely reference it to supplement domestic frameworks, particularly when dealing with contaminant classes or sampling scenarios where local guidance is limited or silent. The National Environment Protection (Assessment of Site Contamination) Measure 1999, as amended in 2013 (NEPM 2013), remains the primary regulatory instrument governing contaminated land assessment in Australia. The PFAS National Environmental Management Plan 3.0, published in March 2025, has expanded the regulatory scope for PFAS investigation and management. Despite these frameworks, prescriptive national guidance on how to sample and characterise microplastics and nanoplastics in soil and groundwater is effectively absent. BS 10175:2026 begins to fill that methodological gap.

The significance of this revision extends to developers undertaking brownfield redevelopment, legal practitioners advising on property transactions, councils managing legacy industrial land, and regulators who must evaluate the adequacy of site investigation reports. A site assessment methodology that fails to account for emerging contaminants such as microplastics may be considered inadequate as regulatory expectations tighten, creating real financial and legal exposure for proponents. Understanding what the revised standard introduces, and how it maps to the Australian regulatory environment, is therefore a practical necessity for professionals working on contaminated land today.

Key Details of BS 10175:2026 and What Has Changed

The 2026 revision of BS 10175 represents the first comprehensive update since the 2011 edition, which had itself built on the 2001 original. The core architecture of the standard, a risk-based, phased approach to site investigation anchored around the source-pathway-receptor pollutant linkage model, remains intact. What the revision adds are structured technical requirements and guidance for contaminant classes that were either not recognised or poorly understood at the time of the previous edition. Chief among these are PFAS and microplastics and nanoplastics, both of which present distinct analytical and sampling challenges that earlier versions of the standard did not address.

On PFAS, the revised standard provides guidance on designing investigations that account for the mobility, persistence, and complex mixture behaviour of PFAS compounds in soil and groundwater systems. PFAS compounds are characterised by their resistance to degradation, their tendency to partition between environmental media, and their capacity to migrate considerable distances from source areas via groundwater. The standard recognises that conventional sampling protocols developed for legacy contaminants such as hydrocarbons or heavy metals are not directly transferable to PFAS investigations without modification, particularly with respect to avoiding cross-contamination during sample collection and selection of appropriate sampling materials and containers.

For microplastics and nanoplastics, the guidance addresses a contaminant class where analytical standardisation is still evolving globally. The standard outlines a phased investigation approach that integrates microplastic and nanoplastic assessment into the CSM development process, requiring practitioners to identify plausible sources, characterise likely pathways, and identify relevant receptors before committing to field sampling programmes. This is methodologically important because microplastic sampling in soil and groundwater requires specific protocols to avoid contamination from sampling equipment itself, a challenge that has contributed to variability in reported data across the scientific literature. The standard does not set numerical guideline values for microplastics, consistent with the absence of such values in most regulatory frameworks globally, but it provides a framework for assessing exposure and risk in the absence of definitive thresholds.

The sustainability and climate change provisions are equally notable. BS 10175:2026 requires practitioners to consider the environmental footprint of the investigation programme itself, including factors such as the carbon intensity of drilling and sampling activities, waste generated during fieldwork, and the long-term resilience of site investigation designs to changing climatic conditions. This means that the design of a Phase 2 environmental site investigation is now expected to include a forward-looking assessment of how climate variables, including changes to rainfall intensity, groundwater recharge rates, and temperature, may affect contaminant behaviour and receptor exposure over the site’s operational life. This moves site investigation from a snapshot activity to one that must account for dynamic environmental conditions.

Australian Context: NEPM 2013, PFAS NEMP 3.0, and the Microplastics Gap in Australian Contaminated Land Practice

Australian contaminated land practice is principally governed

Background and context

BSI Publishes First Major Revision to Contaminated Land Investigation Standard Since 2011, Introducing PFAS and Microplastics Guidance

On 25 March 2026, the British Standards Institution (BSI) published BS 10175:2026 (Investigation of potentially contaminated sites – Code of practice). This marks the first full revision of this foundational site investigation standard in 15 years. Crucially, the updated standard introduces specific guidance on how to approach the investigation and sampling of emerging pollutants, specifically per- and polyfluoroalkyl substances (PFAS) and micro/nano-plastics. It also integrates new sustainability metrics, requiring practitioners to consider climate change resilience and practical actions to reduce the environmental impact of the site investigation process itself.

Why it matters for environmental professionals and their clients:

While BS 10175 is a UK standard, it is globally recognised and frequently referenced by Australian environmental consultants to supplement local frameworks—especially when dealing with emerging contaminants. Although the National Environment Protection (Assessment of Site Contamination) Measure 1999 (as amended 2013) (NEPM 2013) and the PFAS NEMP 3.0 (March 2025) provide the core regulatory structure in Australia, methodologies for investigating microplastics in soil and groundwater remain a grey area.

For Australian practitioners, the release of BS 10175:2026 provides a defensible, internationally peer-reviewed methodology for designing phased site investigations, groundwater sampling, and Conceptual Site Models (CSMs) that account for micro- and nano-plastics. As local regulators increasingly focus on these emerging pollutants, adopting updated international best practices helps consultants future-proof their risk assessments and provides clients with greater certainty during brownfield redevelopment.

Engagement Angle: Did you know that the BBC recently reported thousands of potentially contaminated sites in the UK had never been checked by local authorities? As international standards like BS 10175 tighten to catch emerging pollutants, it serves as a stark reminder of the legacy contamination blind spots that developers and regulators must navigate globally.

References and related sources

• Primary source: www.bsigroup.com
• PFAS National Environmental Management Plan (NEMP)
• NEPM Assessment of Site Contamination

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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: 30 Mar 2026

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