ISO 21365-2019 PDF

Full title and description

ISO 21365:2019 — Soil quality — Conceptual site models for potentially contaminated sites. Guidance for developing, representing, using and updating conceptual site models (CSMs) to support investigation, risk assessment, remediation and any subsequent construction or engineering works at sites where hazardous or potentially harmful substances are present.

Abstract

This International Standard provides guidance on the purpose, structure and stepwise development of conceptual site models (CSMs) for potentially contaminated or known contaminated sites. It describes CSM constituents (sources, contaminated media, migration pathways, receptors and points of exposure), recommended phased development and iterative updating during preliminary assessment, detailed investigation, risk assessment, remediation and later construction. The document emphasises fit‑for‑purpose data collection, transparent documentation of assumptions and uncertainties, and clear representation/communication of the CSM to stakeholders.

General information

• Status: Published (International Standard).
• Publication date: 31 October 2019.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 13.080.01 (Soil quality and pedology — general).
• Edition / version: Edition 1 (2019).
• Number of pages: 40.

Scope

ISO 21365:2019 applies to the development and use of conceptual site models for the management of potentially contaminated sites or sites known to be contaminated. It is intended to be used throughout the phases of site work — from preliminary assessment and site reconnaissance through detailed investigation, baseline human health and environmental risk assessment, remediation planning and implementation, to post‑remediation monitoring and construction or redevelopment. The standard is applicable regardless of whether contaminants are naturally occurring or anthropogenic and focuses on synthesis of available information, formulation and testing of hypotheses, and documenting uncertainties to support decision making.

Key topics and requirements

• Definition of a conceptual site model (CSM) as a synthesis of site information, assumptions and uncertainties relevant to the task.
• Identification and characterisation of sources, contaminated media (soil, groundwater, soil gas, surface water, sediments, biota, buildings), migration pathways and receptors.
• Source–pathway–receptor linkage framework to identify potential exposure scenarios and focus investigations.
• Stepwise, phased approach to CSM development (objectives, boundaries, data collection, model representation, hypothesis testing and iterative refinement).
• Guidance on data quality, fitness‑for‑purpose sampling and documentation to reduce uncertainty.
• Representation and communication techniques (text, maps, tables, diagrams and matrices) for technical and non‑technical stakeholders.
• Use of the CSM to support risk assessment, remediation design, construction planning and long‑term monitoring.
• Requirement to record assumptions, evidence gaps and the rationale for excluding media or pathways.
• Emphasis on periodic review and updating of the CSM as new information becomes available or site conditions change.

Typical use and users

ISO 21365:2019 is used by environmental consultants, site investigators, remediation engineers, risk assessors, regulators and statutory authorities, landowners, developers, construction teams and other stakeholders involved in assessment, management or redevelopment of potentially contaminated land. Typical applications include planning focused site investigations, structuring baseline human health and environmental risk assessments, informing remediation strategies, documenting site decisions for regulatory submissions, and supporting due diligence and redevelopment projects.

Related standards

ISO 21365 is intended to be used alongside other soil and contaminated‑land related standards. Examples include the ISO 18400 series (soil sampling and investigation guidance), ISO 11074 (soil quality — vocabulary/terminology), ISO 19258 (guidance on determination of background values), ISO 18512 (storage of soil samples) and other ISO and national guidance on site investigation, sampling, monitoring and risk assessment. These related documents provide complementary guidance on sampling methods, terminology, sample handling, background data and analytical considerations referenced when preparing CSMs.

Keywords

conceptual site model; CSM; contaminated sites; potentially contaminated sites; soil quality; source‑pathway‑receptor; site investigation; remediation; risk assessment; sampling; monitoring; uncertainty; stakeholders; site characterisation; redevelopment.

FAQ

Q: What is this standard?

A: ISO 21365:2019 is an International Standard providing guidance on preparing, representing, using and updating conceptual site models (CSMs) for potentially contaminated or known contaminated sites.

Q: What does it cover?

A: It covers the purpose and components of CSMs, a stepwise and iterative process for developing models, identification of sources, media, pathways and receptors, data quality considerations, ways to represent and communicate CSMs, and the use of CSMs during investigation, risk assessment, remediation and construction.

Q: Who typically uses it?

A: Environmental consultants and site investigators, remediation engineers, risk assessors, regulators, landowners, developers and construction teams — essentially any party involved in assessing, managing or redeveloping potentially contaminated land.

Q: Is it current or superseded?

A: ISO 21365 was published on 31 October 2019 (first edition). It is an active International Standard intended for use in guiding CSM development. Users should check their national standards bodies or the ISO catalogue for any later revisions or national/adopted versions.

Q: Is it part of a series?

A: ISO 21365 is part of the body of ISO standards dealing with soil quality and contaminated‑land work and is commonly used alongside other ISO documents (for example the ISO 18400 sampling series and ISO vocabulary standards) that together support investigation, sampling, analysis and assessment practices.

Q: What are the key keywords?

A: Conceptual site model, CSM, contaminated site, soil quality, source‑pathway‑receptor, site investigation, remediation, risk assessment, sampling, monitoring, uncertainty, stakeholders.