ISO 22280-1:2026

• Abstract:

  This document sets out the fundamental principles and procedure of determining the groundwater remediation targets for post in situ leach (also referred as in situ recovery) uranium mining. It also delineates the environmental investigation requirements for groundwater remediation, stakeholder identification and engagement, groundwater remediation technical options and their analysis of effectiveness, and considerations for setting and adjusting the groundwater remediation target values. This document is applicable to controlling and mitigating groundwater impact and conducting groundwater remediation for in situ leach uranium mining. It can also serve as a reference for contamination control, mitigation and remediation of groundwater for other in situ leach metal mining projects.

• Status: Published
• Publication Date: 08-Sep-2026
• ICS: 13.060.10 - Water of natural resources
• ICS: 27.120.30 - Fissile materials and nuclear fuel technology
• Technical Committee: ISO/TC 85/SC 5 - Nuclear installations, processes and technologies
• Drafting Committee: ISO/TC 85/SC 5 - Nuclear installations, processes and technologies
• Current Stage: 6060 - International Standard published
• Start Date: 09-Sep-2026
• Due Date: 06-May-2027
• Completion Date: 09-Sep-2026

ISO 22280-1:2026 is an ISO standard for determining groundwater remediation targets after in situ leach uranium mining, also called in situ recovery. It sets the principles and procedure for choosing remediation target values, and it guides the environmental investigation, stakeholder engagement, and technology analysis needed before those targets are set or adjusted.

What does ISO 22280-1:2026 specify?

ISO 22280-1:2026 specifies how to determine groundwater remediation targets for post in situ leach uranium mining. It is also intended as a reference for controlling and remediating groundwater impacts in other in situ leach metal mining projects.

The document is organized into clauses on:

• scope, normative references, and terms and definitions
• fundamental principles
• the procedure to determine remediation targets
• environmental investigation requirements
• stakeholder identification and engagement
• identification of groundwater remediation technology
• determination and adjustment of groundwater remediation target values

What are the key requirements of ISO 22280-1:2026?

ISO 22280-1:2026 ties target setting to safety, site investigation, stakeholder input, technology feasibility, and risk assessment. In practice, a project team has to gather site data first, then compare remediation options, and only then confirm or adjust target values.

Fundamental principles

Clause 4 says remediation targets should protect human health and ecological receptors, rest on scientific rationale, adapt to site conditions, and reflect social and economic responsibility. For operators, this means the target values are not chosen in isolation - they must be realistic, defensible, and linked to the mine closure budget.

Environmental investigation

Clause 6 requires investigation of groundwater use, surrounding conditions, groundwater background quality, and the contamination source term after mining. That matters because target values depend on how the groundwater is used, what natural conditions existed before mining, and how contaminants moved through the aquifer.

Background and source-term data

Clause 6.3 calls for enough background monitoring data to characterize pre-operational groundwater quality and its spatial and seasonal variation. Clause 6.4 then requires post-operation survey of the groundwater contamination source term, using existing wells where possible and extending monitoring when needed. In practice, this is the evidence base for distinguishing natural conditions from mining-related contamination.

Stakeholder identification and engagement

Clause 7 requires early identification of stakeholders and a stakeholder engagement program. ISO 22280-1:2026 expects the operator to consider groups such as nearby communities, regulators, NGOs, investors, and future land and water users. This matters because target values should reflect both technical feasibility and the concerns of affected parties.

Remediation technology options

Clause 8 covers induced remediation, natural attenuation, and enhanced natural attenuation. It also names several methods, including sweeping, extract-treat-reinject recirculation, reverse osmosis, electrodialysis, adsorption, ion exchange, deep well disposal, and solid-waste disposal. The practical point is that target values must fit the selected remediation approach, not the other way around.

Determining and adjusting target values

Clause 9 requires identification of target contaminants, selection of target values, and later adjustment when full-scale remediation proves harder than expected. The clause also links target values to groundwater use, surface water and soil impacts, background quality, and stakeholder consultation. For operators, this gives a structured basis for setting realistic targets and revising them without losing health and environmental protection.

What terms does ISO 22280-1:2026 define?

• groundwater contamination source term - the type, concentration, and distribution of pollutants in the contaminated groundwater area formed by migration from the mining area.
• groundwater remediation - a natural or artificial process that removes, reduces, transfers, or blocks groundwater pollutants.
• induced remediation - human-assisted physical, chemical, or biological processes that reduce contaminant mass, toxicity, mobility, volume, or concentration.
• natural attenuation - natural processes that reduce contamination without human intervention.
• enhanced natural attenuation - natural attenuation that is accelerated by human intervention.
• target contaminant - a groundwater contaminant at or above a level that can harm human health or ecological receptors.
• stakeholder - any person, group, or organization that can affect, or be affected by, mine operation, closure, or remediation.
• lixiviant - the recirculating leaching solution injected into and flowing through an underground ore body.

Who uses ISO 22280-1:2026?

ISO 22280-1:2026 is used by uranium mine operators, closure and remediation planners, hydrogeologists, environmental consultants, and risk assessors. Regulators and reviewers can use it to judge whether a groundwater remediation target-setting process is technically and socially grounded. It is also relevant to stakeholders involved in mine closure planning, especially where groundwater use, public health, or ecological receptors may be affected.

Which standards are used with ISO 22280-1:2026?

• ISO 20305, Mine closure and reclamation - Vocabulary - provides the vocabulary used in the document’s terms and definitions.
• ISO 21795-2, Mine closure and reclamation planning - Part 2: Guidance - supports the stakeholder identification and engagement program in clause 7.

What does the ISO 22280-1:2026 document contain?

ISO 22280-1:2026 contains a procedure figure for determining groundwater remediation targets, plus detailed clauses on investigations, engagement, technology selection, and target adjustment. It gives guidance on groundwater use surveys, surrounding-condition assessment, background monitoring, and post-mining source-term surveys.

The document also describes how to compare remediation alternatives using effectiveness, cost, duration, waste generation, resource consumption, operability, and acceptability. It supports technical planning for design, monitoring, remediation selection, and closure decision-making.

Its technical detail includes example monitoring parameters such as U, Cd, As, SO4, pH, TDS, and Ra, along with methods for monitoring well planning and natural attenuation review.

International
Standard
ISO 22280-1
First edition
Groundwater remediation for in
2026-09
situ leach uranium mining —
Part 1:
Determination of remediation
targets
Remédiation des eaux souterraines post exploitation minière
d’uranium par lixiviation in situ —
Partie 1: Détermination des cibles de remédiation
Reference number
© ISO 2026
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Fundamental principles . 3
4.1 Safety.3
4.2 Scientific rationale .3
4.3 Adaptability .3
4.4 Social and economic responsibility .4
5 Procedure to determine remediation targets . 4
6 Environmental investigation requirements for in situ leach uranium mining . 4
6.1 Investigation of groundwater uses . .4
6.2 Investigation of surrounding conditions.4
6.3 Groundwater background condition investigation.5
6.4 Groundwater contamination source term investigation following the mining operations .6
7 Stakeholder identification and engagement . 6
7.1 General .6
7.2 Stakeholder identification .6
7.3 Stakeholder engagement program . .6
8 Identification of groundwater remediation technology. 7
8.1 Preliminary analysis of groundwater remediation techniques .7
8.2 Determination of technical alternatives.7
8.3 Identification of optimal technical options through analysis of effectiveness .7
9 Determination and adjustment of groundwater remediation target values . 8
9.1 Identification of target contaminants .8
9.2 Determination of groundwater remediation target values .8
9.3 Adjustment of groundwater remediation target values .9
Bibliography .10

iii
Foreword
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radiological protection, Subcommittee SC 5, Nuclear installations, processes and technologies.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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iv
Introduction
Uranium in situ leach mining has many unique advantages compared to conventional mining technologies,
such as: small investment, short construction period, little production cost, less energy consumption, low
labour intensity, high production efficiency, no tailings and waste rock, and minimal impact on the natural
landscape. Uranium production by in situ leach has ranked first among various uranium mining/milling
[1]to[5]
methods since 2009 , among which the global production of natural uranium produced by in situ leach
[6]
reached approximately 27 773 tU in 2022 , accounting for 56 % of the world's natural uranium production
(49 355 tU).
Groundwater environmental impacts can be substantial due to in situ leach mining and should be considered
[7]
throughout planning, operation and remediation . In the case of Königstein in situ leaching (Germany), a
total of 100 000 t of sulfuric acid was injected with the leaching liquid into the ore deposit. The liquid contains
high contaminant concentrations, for example, expressed as multiples of the drinking water standards:
cadmium 400x, arsenic 280x, nickel 130x, uranium 83x, etc. This liquid presents a hazard to an aquifer that
is of importance for the drinking water supply of the region. Groundwater impact is much larger at the Czech
in situ leaching site of Stráz pod Ralskem: 28,7 million m of contaminated liquid is contained in the leaching
zone, covering an area of 5,74 km . This zone contains a total of 1,5 million tonnes of sulphate, 37,500 t of
ammonium, and others. The contaminated liquid has spread out beyond the leaching zone horizontally and
2 3
vertically, thus contaminating another area of 28 km and a further 235 million m of groundwater.
Decommissioning and environmental remediation are the last steps in the whole process of site selection,
design, operation, and decommissioning of nuclear facilities. Determination of groundwater remediation
[8]to[10]
targets is a key point for in situ leach groundwater remediation . No standards on determination of
groundwater remediation targets for in situ leach uranium have been published at the international level.
This document sets out the fundamental principles of determining the groundwater remediation targets
for post in situ leach (also referred as in situ recovery) uranium mining. This document is one of a set of
International Standards on groundwater remediation for in situ leach uranium mining.
This document is formulated in order to manage the groundwater environment protection of uranium in
situ leaching, ensure human health and ecological receptors safety, and standardize the determination of
groundwater remediation target values for uranium in situ leaching.
This document provides the basic principles and procedures for determining the groundwater remediation
target values for in situ leach uranium mining, including requirements for groundwater environmental
investigation, stakeholder engagement, identification of groundwater remediation technology, and
determination and adjustment of groundwater remediation target values.

v
International Standard ISO 22280-1:2026(en)
Groundwater remediation for in situ leach uranium mining —
Part 1:
Determination of remediation targets
1 Scope
This document sets out the fundamental principles and procedure of determining the groundwater
remediation targets for post in situ leach (also referred as in situ recovery) uranium mining. It also delineates
the environmental investigation requirements for groundwater remediation, stakeholder identification
and engagement, groundwater remediation technical options and their analysis of effectiveness, and
considerations for setting and adjusting the groundwater remediation target values.
This document is applicable to controlling and mitigating groundwater impact and conducting groundwater
remediation for in situ leach uranium mining. It can also serve as a reference for contamination control,
mitigation and remediation of groundwater for other in situ leach metal mining projects.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 20305, Mine closure and reclamation — Vocabulary
ISO 21795-2, Mine closure and reclamation planning — Part 2: Guidance
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 20305, ISO 21795-2 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org
3.1
groundwater contamination source term
type, concentration and distribution of pollutants in groundwater contaminated area formed by migration
from the in situ leach uranium mining area to the surrounding area
3.2
groundwater remediation
natural or artificial process of degrading, adsorbing, transferring or blocking pollutants in groundwater
through physical, chemical or biological means
Note 1 to entry: This process converts toxic and harmful pollutants into harmless substances, or reduces their
concentration to acceptable levels, or blocks their exposure pathways to meet the established targets.

3.3
induced remediation
physical, chemical or biological processes in the environment induced by humans that act to reduce the
mass, toxicity, mobility, volume or concentration of contaminants
Note 1 to entry: These human-induced enhancements include extraction of contaminated groundwater, injection of
clean water (including clean water produced through treating contaminated groundwater at the ground surface), and
injection of chemical agents or biological agents.
3.4
natural attenuation
naturally occurring physical, chemical or biological processes in the environment that act without human
intervention to reduce the mass, toxicity, mobility, volume or concentration of contaminants
Note 1 to entry: These in situ natural attenuation processes include biodegradation, dispersion, dilution, sorption,
volatilization, radioactive decay, and chemical or biological stabilization, transformation, or destruction.
Note 2 to entry: Monitored natural attenuation (MNA) emphasizes the need for monitoring when natural attenuation
is deemed a suitable mitigation strategy for a site, and thus is increasingly recognized as a standard approach.
3.5
enhanced natural attenuation
physical, chemical or biological processes in the environment that act with human intervention to accelerate
the natural attenuation (3.4) of contaminants
3.6
target contaminant
contaminant of which quantity or concentration in the groundwater has reached or naturally exceeds a level
that has actual or potential adverse effects on human health and ecological receptors
3.7
targets
groundwater remediation (3.2) endpoints where target contaminants (3.6) and their acceptable concentrations
identified through groundwater environmental surveys or risk assessment do not pose direct or potential
risks to human health, ecological receptors, or the environment
Note 1 to entry: It can be determined based on the natural background groundwater quality in the mining area
before mining activities if groundwater is unsuitable for human consumption due to naturally high concentrations of
uranium, radium, heavy metals, and other substances.
3.8
groundwater background concentration
concentration ranges of chemical constituents (e.g. ions, trace elements and isotopes) in groundwater
systems that exist under natural conditions in a geographic area unaffected or minimally influenced by
human activities before mining operation
Note 1 to entry: These values are determined by natural geological, hydrological, and biogeochemical processes,
serving as a baseline to differentiate natural variability from anthropogenic contamination.
3.9
stakeholder
interested party
any individual, group or organization with the potential to affect, or to be affected by, the process or outcome
of mine operation, closure and remediation
Note 1 to entry: It can include internal and external stakeholders such as the host community, regulators, non-
government organizations, and other community groups, as well as future users and investors of the site.

3.10
lixiviant
recirculating leaching solution that is injected into and percolates through an underground ore body with
valuable metals recovered and/or leaching agents added at the ground surface
Note 1 to entry: Leaching agents may include oxidizers, alkaline or acidic reagents, or CO .
3.11
sweeping
groundwater remediation (3.2) process where residual lixiviant (3.10) is extracted through injection and
production wells, while fresh water is allowed to flow into the leaching zone from the outside to dilute and
displace the lixiviant (3.10) trapped in the pore spaces
3.12
extract-treat-reinject recirculation
closed-loop groundwater remediation (3.2) process where contaminated groundwater of aquifer is extracted,
treated to remove contaminants or recover constituents, and subsequently reinjected into the original
aquifer for recirculation
3.13
deep well disposal
process where waste fluid is injected into deep underground aquifers, confining it within geological
formations to isolate it from the biosphere
Note 1 to entry: The depth of deep well disposal typically ranges from approximately 800 m to over 3 000 m, which is
related to the stratigraphic depth of the local groundwater.
3.14
solid-waste disposal
process of collecting, treating, and finally placing solid waste from groundwater remediation (3.2) in
designated facilities
4 Fundamental principles
4.1 Safety
Groundwater remediation targets should be established to prevent adverse effects to human health and
ecological receptors.
4.2 Scientific rationale
Remediation targets are set scientifically and reasonably based on sound science and effectiveness analysis
of groundwater remediation, taking into account the degree and extent of groundwater contamination,
hydrogeological conditions, initial groundwater characteristics, feasibility of groundwater remediation
technology, remediation duration, as well as the impact on human health and environment.
4.3 Adaptability
The groundwater remediation targets should be adapted with the uranium in situ leach processes,
background groundwater quality, original use of groundwater surrounding the in situ leach well field and
processing facilities. The remediation target values should comply with applicable requirements when
existing.
The determination method of these remediation targets is not applicable to groundwater remediation of
non-mining aquifers resulting from accidental spills of in situ leach uranium mining.

4.4 Social and economic responsibility
The determination of groundwater remediation targets for in situ leach uranium mining should take into
account capabilitie
...