EN ISO 21365:2020 PDF

Overview

EN ISO 21365:2020 (ISO 21365:2019) - "Soil quality - Conceptual site models for potentially contaminated sites" provides guidance for developing and using conceptual site models (CSMs) across investigation, remediation and subsequent construction or engineering works. The standard defines what a CSM is, its core constituents, and promotes an iterative, dynamic approach to CSM development for effective management of potentially contaminated sites and naturally elevated concentrations of substances.

Key topics

• Purpose and scope of CSMs: synthesis of site information with interpretation, assumptions and uncertainties to support decision-making.
• Core constituents: identification and characterization of sources, contaminated media (soil, groundwater, soil gas, surface water, sediments, biota, buildings), migration pathways, receptors and points of exposure.
• Source–pathway–receptor linkages: framing contaminant linkages to assess risk potential.
• Step-wise development: guidance through stages such as defining objectives and boundaries, characterizing sources/media, identifying pathways and receptors, and considering foreseeable events.
• Phased application during investigation: use of CSMs during preliminary, exploratory, detailed and supplementary investigations to focus sampling and reduce uncertainty.
• Remediation and construction: adapting the CSM to plan remediation/mitigation and to manage risks for later construction or engineering works.
• Representation and communication: effective ways to present CSMs to stakeholders, including non-technical audiences.
• Data collection and quality assurance: emphasis on collecting fit-for-purpose data and documenting uncertainties.
• Links to other standards: references and alignment with ISO sampling and soil terminology standards (e.g., ISO 18400 series, ISO 11074).

Applications and practical value

EN ISO 21365:2020 is a practical tool for:

• Planning efficient, targeted site investigations and sampling strategies.
• Structuring baseline human health and environmental risk assessments.
• Designing and documenting remediation, mitigation and aftercare measures.
• Informing construction planning and engineering decisions on previously contaminated land.
• Supporting due diligence, environmental audits and regulatory submissions.

Who should use it

• Environmental consultants and site investigators
• Remediation engineers and project managers
• Regulators and statutory authorities
• Landowners, developers and construction teams
• Risk assessors, environmental auditors and the public/stakeholder groups

Related standards

• ISO 18400 series (soil and sampling procedures)
• ISO 11074 (soil quality terminology)
• Other ISO and national guidance on contaminated land investigations

EN ISO 21365:2020 helps ensure CSMs are transparent, iterative and fit-for-purpose, improving decision-making for potentially contaminated sites across investigation, remediation and redevelopment projects.