ISO/FDIS 17805

Water quality — Sampling, capture and preservation of environmental DNA from water

Qualité de l'eau — Échantillonnage, collecte et conservation de l’ADN environnemental prélevé dans l’eau

General Information

• Status: Not Published
• ICS: 13.060.70 - Examination of biological properties of water
• Technical Committee: ISO/TC 147/SC 5 - Biological methods
• Drafting Committee: ISO/TC 147/SC 5 - Biological methods
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 30-Mar-2026
• Completion Date: 30-Mar-2026

Relations

• Consolidates: FprEN ISO 17805 - Water quality - Sampling, capture and preservation of environmental DNA from water (ISO/FDIS 17805:2026)
• Effective Date: 12-Feb-2026

Overview

ISO/FDIS 17805: Water Quality - Sampling, Capture and Preservation of Environmental DNA from Water is an important international standard developed by ISO Technical Committee 147/SC 5. This standard provides a comprehensive methodology to efficiently collect, process, and preserve environmental DNA (eDNA) from aquatic environments. By following these standardized procedures, water quality professionals and researchers can ensure the integrity, reliability, and reproducibility of eDNA samples, which is crucial for accurate monitoring of aquatic biodiversity and ecosystem health.

With the increasing adoption of eDNA analysis in the assessment of aquatic organisms, a harmonized approach to water sampling and contamination avoidance has become essential in environmental monitoring, regulatory compliance, and ecological research.

Key Topics

• Sampling Protocols: The standard outlines best practices for collecting water samples that contain eDNA, ensuring representativeness in relation to the spatial, seasonal, and biological variability of aquatic systems.
• Capture Techniques: Guidance is given on various filtration methods, including the use of open, enclosed, and housed filters, to effectively separate eDNA from water.
• Sample Preservation: Procedures for immediate preservation are specified, including the use of ethanol, Longmire’s solution, freezing, or drying, all designed to prevent DNA degradation prior to laboratory analysis.
• Contamination Prevention: Detailed recommendations help users avoid sample cross-contamination, including proper equipment maintenance, field equipment blanks, and personal protective measures.
• Documentation: The standard stresses accurate record-keeping-covering sample identity, collection methods, site particulars, and environmental conditions-to facilitate traceability and reproducibility.
• Equipment and Materials: Specifications for gloves, filters, containers, preservative solutions, and decontamination methods are described to support contamination-free sample collection.

Applications

The procedures in ISO/FDIS 17805 are vital for reliable eDNA-based water quality assessments and have wide-ranging applications:

• Biodiversity Monitoring: Enables detection of microorganisms, plants, and animals in aquatic habitats without the need for direct organism capture, supporting baseline surveys and long-term ecological studies.
• Regulatory Compliance: Assists in meeting national and international legislative requirements such as the European Union Water Framework Directive.
• Environmental Impact Assessments: Facilitates the assessment of biodiversity in water bodies before and after interventions such as construction, restoration, or pollution incidents.
• Conservation and Invasive Species Management: Supports the early detection of endangered or invasive species for more responsive resource management and conservation actions.
• Research and Education: Provides a foundational protocol for academic studies and training on molecular water quality analysis.

Related Standards

ISO/FDIS 17805 aligns with and complements a range of other water quality and environmental standards:

• EN 14011, EN 14757, EN 15460: European standards for organism monitoring in aquatic environments.
• EN ISO 7027-1:2016: Standard for quantitative determination of turbidity in water, relevant for assessing water conditions during sampling.
• CEN/TR 17245: Technical report for sampling diatoms for metabarcoding analyses.
• Nagoya Protocol: International agreement on access to genetic resources, important for legal compliance during sampling.

For optimal results, ISO/FDIS 17805 should be used alongside these standards and regulations to ensure comprehensive and law-abiding environmental DNA sampling and analysis.

---

Keywords: ISO 17805, water quality, environmental DNA, eDNA sampling, sample preservation, aquatic biodiversity, standardization, contamination prevention, water monitoring, filter types, preservation solutions, water sampling protocol.

Standards Content (Sample)

DRAFT
International
Standard
ISO/DIS 17805.2
ISO/TC 147/SC 5
Water quality — Sampling, capture
Secretariat: DIN
and preservation of environmental
Voting begins on:
DNA from water
2025-02-04
ICS: 13.060.70
Voting terminates on:
2025-04-01
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
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TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 17805.2:2025(en)
DRAFT
ISO/DIS 17805.2:2025(en)
International
Standard
ISO/DIS 17805.2
ISO/TC 147/SC 5
Water quality — Sampling, capture
Secretariat: DIN
and preservation of environmental
Voting begins on:
DNA from water
ICS: 13.060.70
Voting terminates on:
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: [phone]
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 17805.2:2025(en)
ii
ISO/DIS 17805.2:2025(en)
Contents Page
European foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Procedure . 3
5.1 General .3
5.2 Considerations prior to fieldwork .4
5.3 Equipment preparation prior to fieldwork .4
5.4 Sampling the eDNA from water .4
5.5 Preserving the sample .5
5.5.1 General .5
5.5.2 Preserving eDNA in enclosed filters .5
5.5.3 Preserving eDNA in open filters .5
5.5.4 Preserving eDNA in housed filters .6
6 Equipment . 6
7 Preservative solutions . 7
7.1 General .7
7.2 Examples of preservative solutions .8
8 Sampling report . 8
8.1 General .8
8.2 Sample identity and characteristics .8
8.3 Sampling site .8
8.4 Sampling conditions .8
8.5 Sampling .9
9 Avoiding sample contamination . . 9
9.1 General .9
9.2 Contamination avoidance .9
9.2.1 Contamination that originates from equipment .9
9.2.2 Contamination that originates from the person taking the samples .9
9.3 Sampling equipment decontamination procedure .10
9.3.1 General .10
9.3.2 Materials and equipment in direct contact with the water sample .10
9.3.3 Materials and equipment not in direct contact with the water sample .10
Annex A (informative) Filter types .11
Bibliography .12

iii
ISO/DIS 17805.2:2025(en)
European foreword
This document (FprEN 17805:2022) has been prepared by Technical Committee CEN/TC 230 “Water
analysis”, the secretariat of which is held by DIN.
This document is currently submitted to the Formal Vote.
Any feedback and questions on this document should be directed to the users’ national standards body. A
complete listing of these bodies can be found on the CEN website.

iv
ISO/DIS 17805.2:2025(en)
Introduction
WARNING — Persons using this document should be familiar with water sampling protocols to
assess biological diversity. This document does not purport to address all of the safety problems, if
any, associated with its use. It is the responsibility of the user to establish appropriate health and
safety practices.
Moreover, the need of notification, obtaining certificates or permits prior to sampling, depending
on national or international laws and regulations such as the Nagoya Protocol on Access to Genetic
Resources (https://www.cbd.int/abs/), needs to be considered.
The monitoring of organisms is key to the assessment of the status of aquatic ecosystems and is required by
national and international legislation such as the European Union Water Framework Directive (2000/60/
EC). A range of methods have been described how to monitor organisms in aquatic environments, leading to a
wide range of European standards (e.g. EN 14011:2003, EN 14757:2005, EN 15460:2007). These approaches,
however, necessitate the capture and/or collection of the organisms of interest, which can be a laborious
and time-consuming process.
The possibility to detect the presence of organisms and/or quantify relative abundance (e.g [6].) in aquatic
environments via the analysis of environmental DNA (eDNA) provides a novel means to monitor biodiversity
[7][8][9]
across a wide range of taxonomic groups, including microorganisms, plants and animals.( ) This
approach allows to examine organismic diversity without the need to directly isolate and capture organisms
and it is expected to play a key role for future biomonitoring aiming at temporally and spatially highly
[10] [11]
resolved species inventories. Albeit the power of the eDNA approach has been repeatedly reported,
[12]
there is a great need for standardizing the application of eDNA-based assessment of aquatic biodiversity.(
[13]
) Note, however, that eDNA-based biomonitoring currently does not allow to obtain certain population
parameters (e.g. individual size, sex) which can be obtained by traditional sampling techniques.
This document provides guidance how to sample and preserve eDNA from water samples, addressing the
first and crucial step for any further downstream eDNA-based analyses of biodiversity. A specific technical
report for the routine sampling of benthic diatoms from rivers and lakes adapted for metabarcoding analyses
is CEN/TR 17245:2018.
In this document, the following verbal forms are used to specify working procedures:
— “shall” indicates a requirement;
— “should” indicates a recommendation;
— “may” indicates a permission;
— “can” indicates a possibility or a capability.

v
DRAFT International Standard ISO/DIS 17805.2:2025(en)
Water quality — Sampling, capture and preservation of
environmental DNA from water
1 Scope
This document specifies procedures for sampling, capture and preservation of environmental DNA (eDNA)
in aquatic environments, stemming from organisms that are or have recently been present in a waterbody,
have visited it or whose DNA has been introduced to the waterbody through some mechanism. This document
also covers procedures for avoiding sample contamination and ensuring DNA quality, key properties of the
filtering procedure and equipment and reporting standards.
This document does not include the collection of eDNA from biofilms, sediments or similar sample types, or
passive sampling methods, and does not cover sampling designs.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
3.1
cross-contamination
unintended transfer of any source and/or DNA from one sample to another sample
3.2
decontamination
procedure to remove any source and/or trace of DNA from material that might come into contact with the sample
3.3
enclosed filter
filtering system where the filter membrane is encapsulated and where the inflow and outflow can be closed
for transport and storage
Note 1 to entry: The eDNA contained on the filter is typically extracted without removing the membrane from the
filter capsule greatly reducing the risk of contamination of samples. See Figure A.1 C. in Annex A.
3.4
environmental DNA
eDNA
material from dead or living organisms including single-stranded (ss) and double-stranded (ds) DNA
fragment from nuclear and mitochondrial/plastid DNA of eukaryotes as well as plasmid chromosomal and
DNA of prokaryotes
Note 1 to entry: Subsuming DNA from various sources such as unicellular or small multicellular organisms or tissue
particles (e.g. shed cells, faeces) and gamets of multicellular organisms.

ISO/DIS 17805.2:2025(en)
3.5
field equipment blank
a sample obtained from processing target DNA-free water (e.g. distilled water) through all the equipment
used and following all procedures involved in the eDNA sampling process to ensure that the equipment and
procedures do not introduce DNA contamination
3.6
housed filter
filtering systems in which a filter membrane is protected within a solid housing during the filtration process,
which is opened subsequently to remove the filter membrane for further processing
Note 1 to entry: The filters are removed from the housing for eDNA extraction. The housing can be opened and the
filter removed for preservation and later processing. See Figure A.1 B. in Annex A.
3.7
lysis buffer
buffer solution to preserve the DNA present in the sample and to lyse/open cells as a first step of the DNA
extraction
3.8
internal positive control
IPC
quantified amount of synthetic or natural DNA containing a PCR-amplifiable sequence that will not naturally
occur in the sample to distinguish types of negative results (no target sequence vs. PCR inhibition)
Note 1 to entry: The IPC can be added to the sample or the preservation/lysis buffer at a known concentration to
verify the efficiencies of DNA preservation, DNA extraction, DNA amplification and DNA identification.
3.9
open filter
filtering system including vacuum filtration units (laboratory) and filtration backpacks (field) from which
the filter membrane has to be removed with tweezers for further processing
Note 1 to entry: See Figure A.1 A. in Annex A
3.10
pre-filter
filter membrane, mesh or hose strainer with a larger pore-size than the main filter membrane (used for
capturing the eDNA) through which water is passed first to remove larger particles of sediment, plant
material or algae to increase the volume of water that can be filtered before saturation of the main filter
3.11
sample contamination
process by which exogenous DNA is unintentionally introduced to the sample
Note 1 to entry: DNA that is already present in the water before the eDNA sampling was undertaken is not considered
as contamination.
3.12
target DNA
any source and/or trace of DNA from the surveyed species/taxa
3.13
enclosed filter
filtering systems in which a filter membrane is protected within a solid housing during filtration and further
processing steps, e.g. lysis; it is not opened, minimizing sample contamination
Note 1 to entry: See Figure A.1 C. in Annex A

ISO/DIS 17805.2:2025(en)
4 Principle
A representative water sample from the surveyed water body is sampled according to an appropriate
sampling design to capture and separate eDNA from the water sample. During the whole procedure cross-
contamination and sample contamination are avoided and eDNA integrity is guaranteed.
An overview on the key steps and considerations for the sampling, capture, and preservation of eDNA from
water in Figure 1.
NOTE Numbers in parentheses refer to the respective clause/subclause.
Figure 1 — Key steps and considerations for the eDNA water sampling process
5 Procedure
5.1 General
Water should be sampled to capture and separate eDNA via filtration or other processes. The probability of
obtaining eDNA from the targeted organism(s) is positively correlated with:
— the number of samples per waterbody;

ISO/DIS 17805.2:2025(en)
— the spatial representativeness of the samples;
— the volume of water filtered;
— the optimum sampling time point/season with regard to the organism(s) eDNA shedding rates,
[15][16]
abundances (also of non-target organisms) including spawning time,( ) metabolic activity and
locomotion.
5.2 Considerations prior to fieldwork
Depending on the different applications/goals of each eDNA survey, the most appropriate sampling conditions
and design shall be assessed based on case-by-case evidence to obtain water samples representative of the
water body and the organisms being monitored. These might include hydrological, meteorological, seasonal/
temporal and biological/ecological and physiological variation.
This is particularly important in lentic (non-flowing) water bodies since eDNA is often unevenly distributed
when the water is not well mixed. Representative sampling can be achieved by combining subsamples
collected at different points in the water body, or alternatively by continuous sampling systems that move
across the water body while drawing up water. When surveying deep water bodies and targeting deep water
dwelling organisms, it may be necessary to sample water from depth.
To maximize the probability of capturing target DNA, the following shall be considered when planning
where and when to collect samples and subsamples:
1) Features of the water body, including its size, depth, flow, stratification and the distribution of
microhabitats as well as inlets/outlets of the waterbody. If the study requires separate analyses of
subsamples (for example biota in different depth layers), new or clean collection vessels shall be used
for each subsample.
2) Biology of all target taxa, including habitat preferences and lifecycle. Detection probability for individual
species can be increased by timing sampling to coincide with times of intense activity (e.g. spawning).
Temporal variations in the amounts of released eDNA by the target species needs to be considered. It is
also important to consider whether target taxa are likely to be present in the water body at the time of
sampling, especially in the case of amphibious or (diurnally) migratory species.
5.3 Equipment preparation prior to fieldwork
Prior to fieldwork a sufficient number of collecting vessels and equipment shall be cleaned to avoid
contamination (for detailed instruction see 9).
5.4 Sampling the eDNA from water
Various systems are used for sampling and filtering water. Some involve initially gathering water into a
collecting vessel where it is mixed and then filtered subsequently; other systems filter the water directly as
it is drawn up from the water body. When the water is not filtered directly in the water body, the filtration
can be carried out on the shore or in the laboratory.
Water shall be sampled and/or filtered to capture tissue fragments, cells and DNA. This may be achieved
manually with syringes or using a hand or powered pump or by gravity filtration/centrifugation, where it
has been demonstrated to work. If a pump is used and water passes through a pump tubing before reaching
a filter then a new or decontaminated pump tubing shall be used for each sample.
If subsamples are being merged into a pooled sample, ensure
...

FINAL DRAFT
International
Standard
ISO/TC 147/SC 5
Water quality — Sampling, capture
Secretariat: DIN
and preservation of environmental
Voting begins on:
DNA from water
2026-03-30
Qualité de l'eau — Échantillonnage, collecte et conservation de
Voting terminates on:
l’ADN environnemental prélevé dans l’eau
2026-05-25
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 147/SC 5
Water quality — Sampling, capture
Secretariat: DIN
and preservation of environmental
Voting begins on:
DNA from water
Qualité de l'eau — Échantillonnage, collecte et conservation de
Voting terminates on:
l’ADN environnemental prélevé dans l’eau
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Procedure . 4
5.1 General .4
5.2 Considerations prior to fieldwork .5
5.3 Equipment preparation prior to fieldwork .5
5.4 Sampling the eDNA from water .5
5.5 Preserving the sample .6
5.5.1 General .6
5.5.2 Preserving eDNA in enclosed filters .6
5.5.3 Preserving eDNA in open filters .6
5.5.4 Preserving eDNA in housed filters .7
6 Equipment and its use . 7
7 Preservative solutions . 8
7.1 General .8
7.2 Examples of preservative solutions that can be made in-house .9
8 Sampling report . 9
8.1 General .9
8.2 Required parameters .9
8.3 Highly recommended parameters .10
8.4 Recommended parameters .10
9 Avoiding sample contamination . .11
9.1 General .11
9.2 Contamination avoidance .11
9.2.1 Contamination that originates from equipment and people during sample
collection and processing .11
9.3 Sampling equipment decontamination procedure .11
9.3.1 General .11
9.3.2 Materials and equipment in direct contact with the water sample . 12
9.3.3 Materials and equipment not in direct contact with the water sample . 12
Annex A (informative) Filter types .13
Annex B (informative) Metadata .15
Bibliography . 17

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 5,
Biological methods, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 230, Water analysis, in accordance with the Agreement on technical cooperation between
ISO and CEN (Vienna Agreement).
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
The monitoring of organisms is key to the assessment of the status of aquatic ecosystems and is required by
national and international legislation such as the European Union Water Framework Directive (2000/60/
EC). A wide range of methods exist that describe how to monitor organisms in aquatic environments (e.g.
[2] [3] [4]
EN 14011 , EN 14757 , EN 15460 ). These approaches, however, necessitate either the capture or
collection, or both, of the organisms of interest, which can be a laborious and time-consuming process.
The possibility either to detect the presence of organisms or quantify relative abundance (e.g. see
Reference [7]), or both, in aquatic environments via the analysis of environmental DNA (eDNA) provides
a novel mean to monitor biodiversity across a wide range of taxonomic groups, including microorganisms,
[8][9][10]
plants and animals . This approach allows examination of organismic diversity without the need to
directly isolate and capture organisms and it is expected to play a key role for future biomonitoring aiming
[11]
at species inventories with high temporal and spatial resolution . Albeit the power of the eDNA approach
[12]
has been repeatedly reported , there is a great need for standardizing the application of eDNA-based
[13][14]
assessment of aquatic biodiversity .
This document addresses the first crucial step for any further downstream eDNA-based analyses of
biodiversity. Routine sampling of benthic diatoms from rivers and lakes adapted for metabarcoding analyses
[5]
is given in CEN/TR 17245 .
v
FINAL DRAFT International Standard ISO/FDIS 17805:2026(en)
Water quality — Sampling, capture and preservation of
environmental DNA from water
WARNING — Persons using this document should be familiar with water sampling protocols to
assess biological diversity. This document does not purport to address all of the safety problems, if
any, associated with its use. It is the responsibility of the user to establish appropriate health and
safety practices.
1 Scope
This document specifies procedures for sampling, capture and preservation of environmental DNA (eDNA)
in aquatic environments, stemming from organisms
— that are or have recently been present in a water body, or
— whose DNA has been introduced to the water body through some mechanism.
This document also specifies procedures for avoiding sample contamination and ensuring environmental
DNA integrity during water filtration and sample preservation. It also specifies the required equipment and
metadata reporting.
This document excludes:
— methods for the collection of eDNA from biofilms, sediments or similar sample types;
— passive sampling methods;
— sampling designs.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
cross-contamination
unintended transfer of any source of DNA from one sample to another sample
3.2
decontamination
procedure to remove any source of trace of DNA from material that can come into contact with the sample

3.3
enclosed filter
filtering system where the filter membrane is encapsulated and where the inflow and outflow can be closed
for transport and storage
Note 1 to entry: The eDNA contained on the filter is typically extracted without removing the membrane from the filter
capsule greatly reducing the risk of contamination of samples. See Figure A.1 c) for further description and illustration
of the filter type, filtering and lysis step.
3.4
environmental DNA
eDNA
nucleic acids from dead or living organisms including single-stranded (ss) and double-stranded (ds) DNA
fragment from nuclear and mitochondrial or plastid DNA of eukaryotes as well as plasmid and chromosomal
DNA of prokaryotes
Note 1 to entry: Including DNA from various sources such as unicellular or small multicellular organisms or tissue
particles (e.g. shed cells, faeces), and gametes of multicellular organisms.
3.5
environmental DNA field blank
eDNA field blank
sample obtained from processing target DNA-free water (e.g. molecular grade water) through all the
equipment used and following all procedures involved in the eDNA sampling process to check whether the
equipment and procedures introduced either sample contamination (3.11) or cross-contamination (3.1), or
both
3.6
housed filter
filtering systems in which a filter membrane is protected within a solid housing during the filtration process,
which is opened subsequently to remove the filter membrane with tweezers for further processing
Note 1 to entry: The filters are removed from the housing for eDNA extraction. The housing can be opened and the
filter removed for preservation and later processing. See Figure A.1 b) for further description and illustration of the
filter type, filtering and lysis step.
3.7
lysis buffer
buffer solution to preserve the DNA present in the sample and to lyse or open cells as a first step of the DNA
extraction
3.8
internal positive control
IPC
quantified amount of synthetic or natural DNA containing a PCR-amplifiable sequence that does not naturally
occur in the sample, used to interpret negative results
Note 1 to entry: The IPC can be added to the sample, the preservation buffer or the lysis buffer (3.7) at a known
concentration to verify the efficiency of the entire workflow from DNA preservation to DNA amplification. To
determine the efficiency of specific steps in the workflow such as the DNA extraction or DNA amplification, the IPC is
added prior to the respective step within the workflow.
3.9
open filter
filtering system from which the filter membrane is removed with tweezers for further processing
Note 1 to entry: The filtering system can include vacuum or peristaltic units. See Figure A.1 a) for further description
and illustration of the filter type, filtering and lysis step.

3.10
pre-filtration
use of a filter membrane, mesh or hose strainer with a larger pore-size than the main filter membrane (used
for capturing the eDNA) through which water is passed first to remove larger particles of sediment, plant
material or algae to increase the volume of water that can be filtered before saturation of the main filter
3.11
sample contamination
process by which exogenous DNA is unintentionally introduced to the sample
Note 1 to entry: DNA that is already present in the water before the eDNA sampling was undertaken is not considered
as contamination.
3.12
target DNA
source or trace, or both, of DNA from the surveyed species or taxa
4 Principle
eDNA is captured and separated from the surveyed water body via a representative water sample,
according to an appropriate sampling design. During the whole procedure, cross-contamination and sample
contamination are avoided and eDNA integrity is maintained.
An overview on the key steps and considerations for the sampling, capture and preservation of eDNA from
water is shown in Figure 1.
Figure 1 — Key steps and considerations for the eDNA water sampling process
5 Procedure
5.1 General
Water should be sampled to capture and separate eDNA via filtration, centrifugation or gravity filtration.
[15]
The probability of obtaining eDNA from the targeted organism(s) is positively correlated with :
— the optimum sampling location and time point (including season) with regard to the organism(s) eDNA
[16][17]
shedding rates, abundances (also of non-target organisms) including spawning time, metabolic
activity and locomotion;
— the volume of water filtered;

— the spatial representativeness of the samples;
— the number of samples per water body.
5.2 Considerations prior to fieldwork
Depending on the different applications or goals of each eDNA survey, the most appropriate sampling
conditions and design shall be assessed based on case-by-case evidence to obtain water samples
representative of the water body and the organisms being monitored. These can include hydrological,
meteorological, seasonal or temporal, biological or ecological, and physiological variation.
This is particularly important in lentic (non-flowing) water bodies since eDNA is often unevenly distributed
[18][19]
when the water is not well mixed. Representative sampling can be achieved by merging (i.e. pooling)
subsamples collected at different points in the water body or alternatively by continuous sampling systems
that move across the water body while drawing up water. When surveying deep water bodies and targeting
deep water dwelling organisms, water should be sampled from relevant depths (e.g. with Niskin samplers;
for decontamination processes, see Clause 9).
The following shall be considered when planning where and when to collect samples and subsamples:
— Features of the water body, including its size, depth, flow, stratification and the distribution of
microhabitats as well as inlets and outlets of the water body. If the study requires separate analyses of
subsamples (e.g. biota in different depth layers), new or clean collection vessels shall be used for each
subsample.
[20]
— Biology of all target taxa, including habitat preferences, life cycle and (if known) DNA shedding rates.
[21]
Detection probability for individual species can be increased by timing sampling to coincide with
times of intense activity (e.g. spawning). Temporal variations in the amounts of released eDNA by the
target species needs to be considered. It is also important to consider whether target taxa are likely to
be present in the water body at the time of sampling.
NOTE Pooling of samples can lead to a decreased chance of detecting rare targets.
5.3 Equipment preparation prior to fieldwork
Prior to fieldwork a sufficient number of collecting vessels and equipment shall be cleaned to avoid
contamination (for detailed instruction, see Clause 9).
5.4 Sampling the eDNA from water
Various systems are used for sampling and filtering water. Some involve initially gathering water into a
collecting vessel where it is mixed and then filtered subsequently; other systems filter the water directly as
it is drawn up from the water body. When the water is not filtered directly in the water body, the filtration
can be carried out on the shore, on boats, or in the laboratory.
eDNA, tissue fragments, cells and (in case of microbial communities) whole organisms shall be separated
from the collected water via filtration or other processes (e.g. including gravity filtration and centrifugation).
This can be achieved manually with syringes or using a hand or powered pump or by gravity filtration or
centrifugation, where it has been demonstrated to work. If a pump is used and water passes through a pump
tubing before reaching a filter, then a new or decontaminated pump tubing shall be used for each sample.
If subsamples are being merged into a pooled sample, ensure that they are well mixed before starting to
filter.
When sampling eDNA, precaution measures shall be considered to avoid contamination (for detailed
instruction, see Clause 9).
5.5 Preserving the sample
5.5.1 General
The eDNA contained in the collected water should be separated from the water immediately in the field.
Note that DNA breakdown will occur when it is not possible to immediately separate and preserve the
collected water sample on-site. The rate at which this breakdown occurs, depends on several parameters
such as chemical composition of the collected water, storage conditions of the water sample, exposure to
sunlight (e.g. UV), as well as the type of organism releasing the eDNA. In general, the longer the period
between collection and preservation, the more eDNA will be broken down. Note that at room temperature,
large amounts of target eDNA can be lost within 12 h to 24 h. When it is not possible to separate the eDNA
from the water on-site, then separation should be undertaken as soon as possible (usually no longer than
[22]
6 hours unless a preservation method is used to elongate the storage period (see e.g. Reference [23]).
Water shall be stored ≤ 8 °C and protected from UV light prior to separating eDNA from the collected water
by filtration or centrifugation. The obtained eDNA sample (e.g. filter, centrifuged pellet) shall be immediately
preserved in the field for transportation to the laboratory and storage prior to eDNA extraction. In case the
eDNA collected on a filter membrane has to be preserved (i.e. is not directly used for lysis), the membrane
shall be either completely covered by preservation solution or be frozen (≤−18 °C), or both, or desiccated,
depending on filter type and manufacturer’s recommendation. Maximum storage time of filters depends on
the DNA preservation method used.
If a preservative solution is used, the solution used shall be clearly recorded because downstream laboratory
protocols for DNA extraction may need to be modified according to the preservative solution used. If
freezing is used for preservation, the filter membrane should either be frozen immediately after filtration is
completed or kept at 5 °C ± 3 °C no longer than 3 h (part of the 6 h mentioned before) and protected from UV
light. Once the filter is frozen, it should remain continuously so until DNA extraction begins.
An IPC should be added before preserving filter samples to allow for monitoring eDNA degradation during
transport and storage of the sample. It is recommended to include an IPC in the preservative solution that
can be quantified after storage and DNA extraction using a quantitative PCR assay (e.g. quantitative PCR or
digital droplet PCR) to track sample degradation. If using freezing or drying and also using an IPC, add the
IPC to the filter membrane with the lysis buffer during the first phase of the DNA extraction and this will
serve only as an indication of successful DNA extraction; it will not serve as a degradation control.
Additional requirements for different filter types are mentioned 5.5.2 to 5.5.4.
NOTE The obtained type of eDNA depends on the preservation method. While freezing the samples breaks up
the cells which release the intracellular DNA therein, other preservation methods without freezing and depending on
the type of preservation liquid used, preserve the extracellular eDNA which then can be separately extracted from
the intracellular DNA contained in cells and tissues. For further information on the preservation and extraction of
different eDNA fractions, see Reference [24].
5.5.2 Preserving eDNA in enclosed filters
If using an enclosed filter and a preservative solution, the filter unit shall be securely sealed to ensure that
the preservative solution fully covers the filter membrane throughout transportation and storage of the
filter until such time as DNA extraction begins. The temperature of the filter should be subjected to the
previously recommended temperature during transport and storage until DNA extraction, depending on the
type of preservative solution used.
If the filter cases are cracked in the laboratory (not recommended), they should be processed as housed
filters regarding contamination risk.
5.5.3 Preserving eDNA in open filters
If using an open filter, care shall be taken to not contaminate the sample. Handling of the filter membrane
shall be done using decontaminated tweezers.
NOTE Transferring the filter carries a risk of contamination.

If drying is used for preservation, then the filter membrane shall be sealed inside a DNA-free, air-proof
container along with a suitable drying agent until DNA extraction begins.
5.5.4 Preserving eDNA in housed filters
If using a housed filter that is opened in the field, care shall be taken to avoid contaminating the samples.
Preservative solutions can be added directly to the filter membrane inside the housing and transported to
the laboratory depending on the manufacturer. Filt
...

ISO/DISFDIS 17805.2:2025(en)
ISO/TC 147/SC 5
Secretariat: DIN
Date: 2026-03-16
Water quality — Sampling, capture and preservation of
environmental DNA from water
Qualité de l’eau — Techniques de récoltel'eau — Échantillonnage, collecte et conservation de l’ADN
environnemental à partir d’échantillons d’eauprélevé dans l’eau
First edition
Date: 2025-06-11
TThhiis drs draafftt i is s susubbmimitttteed d ttoo aa ppaarraallellel l vvoottee i inn IISSOO,, C CEEN.N.

FprEN 17805:2022 (E)
FDIS stage
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO'sISO’s member body in the country of the requester.
ISO Copyright Officecopyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
Email: E-mail: [e-mail]
Website: www.iso.org
Published in Switzerland.
iii
Contents
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Procedure . 5
5.1 General . 5
5.2 Considerations prior to fieldwork . 6
5.3 Equipment preparation prior to fieldwork . 6
5.4 Sampling the eDNA from water . 6
5.5 Preserving the sample . 7
6 Equipment and its use . 8
7 Preservative solutions . 10
7.1 General . 10
7.2 Examples of preservative solutions that can be made in-house . 10
8 Sampling report . 10
8.1 General . 10
8.2 Required parameters . 11
8.3 Highly recommended parameters . 11
8.4 Recommended parameters . 12
9 Avoiding sample contamination . 12
9.1 General . 12
9.2 Contamination avoidance . 13
9.3 Sampling equipment decontamination procedure. 13
Annex A (informative) Filter types . 15
Annex B (informative) Metadata . 17
Bibliography . 19

iv
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 5,
Biological methods, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 230, Water analysis, in accordance with the Agreement on technical cooperation between
ISO and CEN (Vienna Agreement).
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
Introduction
WARNING — Persons using this document should be familiar with water sampling protocols to assess
biological diversity. This document does not purport to address all of the safety problems, if any,
associated with its use. It is the responsibility of the user to establish appropriate health and safety
practices.
The monitoring of organisms is key to the assessment of the status of aquatic ecosystems and is required by
national and international legislation such as the European Union Water Framework Directive (2000/60/EC).
A wide range of methods exist that describe how to monitor organisms in aquatic environments, leading to a
[2] [3] [4]
wide range of European standards (e.g. EN 14011 ,, EN 14757 ,, EN 15460 ).). These approaches, however,
necessitate either the capture or collection, or both, of the organisms of interest, which can be a laborious and
time-consuming process.
The possibility either to detect the presence of organisms or quantify relative abundance (e.g. see
Reference [7] [6]),), or both, in aquatic environments via the analysis of environmental DNA (eDNA) provides
a novel mean to monitor biodiversity across a wide range of taxonomic groups, including microorganisms,
[8]][[9]][[10] [7][8][9]
plants and animals . . This approach allows examination of organismic diversity without the need
to directly isolate and capture organisms and it is expected to play a key role for future biomonitoring aiming
[11] [10]
at species inventories with high temporal and spatial resolution . . Albeit the power of the eDNA approach
[12] [11]
has been repeatedly reported , , there is a great need for standardizing the application of eDNA-based
[13]][[14] [12][13]
assessment of aquatic biodiversity . .
This document provides guidance how to sample and preserve eDNA from water samples,
addressingaddresses the first and crucial step for any further downstream eDNA-based analyses of
biodiversity. A specific technical report for the routineRoutine sampling of benthic diatoms from rivers and
[5]
lakes adapted for metabarcoding analyses is given in CEN/TR 17245 .
vi
Water quality — Sampling, capture and preservation of
environmental DNA from water
WARNING — Persons using this document should be familiar with water sampling protocols to assess
biological diversity. This document does not purport to address all of the safety problems, if any,
associated with its use. It is the responsibility of the user to establish appropriate health and safety
practices.
1 Scope
This document specifies procedures for sampling, capture and preservation of environmental DNA (eDNA) in
aquatic environments, stemming from organisms that are or have recently been present in a water body, or
whose DNA has been introduced to the water body through some mechanism. This document also covers
procedures for avoiding sample contamination and ensuring DNA quality, key properties of the filtering
procedure and equipment and reporting standards.
— that are or have recently been present in a water body, or
— whose DNA has been introduced to the water body through some mechanism.
This document does not includealso specifies procedures for avoiding sample contamination and ensuring
environmental DNA integrity during water filtration and sample preservation. It also specifies the required
equipment and metadata reporting.
This document excludes:
— methods for the collection of eDNA from biofilms, sediments or similar sample types, or ;
— passive sampling methods. This document does not cover ;
— sampling designs.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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 3.1
cross-contamination
unintended transfer of any source of DNA from one sample to another sample
3.2 3.2
decontamination
procedure to remove any source of trace of DNA from material that can come into contact with the sample
3.3 3.3
enclosed filter
filtering system where the filter membrane is encapsulated and where the inflow and outflow can be closed
for transport and storage
Note 1 to entry: The eDNA contained on the filter is typically extracted without removing the membrane from the filter
capsule greatly reducing the risk of contamination of samples. See Figure A.1Figure A.1 C c) for further description and
illustration of the filter type, filtering, and lysis step.
3.4 3.4
environmental DNA
eDNA
nucleic acids from dead or living organisms including single-stranded (ss) and double-stranded (ds) DNA
fragment from nuclear and mitochondrial or plastid DNA of eukaryotes as well as plasmid and chromosomal
DNA of prokaryotes
Note 1 to entry: Including DNA from various sources such as unicellular or small multicellular organisms or tissue
particles (e.g. shed cells, faeces), and gametes of multicellular organisms.
3.5
3.5
environmental DNA field blank
eDNA field blank
sample obtained from processing target DNA-free water (e.g. molecular grade water) through all the
equipment used and following all procedures involved in the eDNA sampling process to check ifwhether the
equipment and procedures introduced neithereither sample contamination (3.11nor) or cross-contamination
(3.1,), or both
3.53.6 3.6
housed filter
filtering systems in which a filter membrane is protected within a solid housing during the filtration process,
which is opened subsequently to remove the filter membrane with tweezers for further processing
Note 1 to entry: The filters are removed from the housing for eDNA extraction. The housing can be opened and the filter
removed for preservation and later processing. See Figure A.1Figure A.1 B b) for further description and illustration of
the filter type, filtering, and lysis step.
3.63.7 3.7
lysis buffer
buffer solution to preserve the DNA present in the sample and to lyse or open cells as a first step of the DNA
extraction
3.73.8 3.8
internal positive control
IPC
quantified amount of synthetic or natural DNA containing a PCR-amplifiable sequence that willdoes not
naturally occur in the sample, used to interpret negative results
Note 1 to entry: The IPC can be added to the sample or, the preservation buffer or the lysis buffer (3.7) at a known
concentration to verify the efficiency of the entire workflow from DNA preservation to DNA amplification. To determine
the efficiency of specific steps in the workflow such as the DNA extraction or DNA amplification, the IPC needs to beis
added prior to the respective step within the workflow.
3.83.9 3.9
open filter
filtering system from which the filter membrane has to beis removed with tweezers for further processing
Note 1 to entry: The filtering system can include vacuum or peristaltic units. See Figure A.1Figure A.1 A a) for further
description and illustration of the filter type, filtering, and lysis step.
3.93.10 3.10
pre-filterfiltration
use of a filter membrane, mesh or hose strainer with a larger pore-size than the main filter membrane (used
for capturing the eDNA) through which water is passed first to remove larger particles of sediment, plant
material or algae to increase the volume of water that can be filtered before saturation of the main filter
3.103.11 3.11
sample contamination
process by which exogenous DNA is unintentionally introduced to the sample
Note 1 to entry: DNA that is already present in the water before the eDNA sampling was undertaken is not considered as
contamination.
3.113.12 3.12
target DNA
either any source or trace, or both, of DNA from the surveyed species or taxa
4 Principle
eDNA is captured and separated from the surveyed water body via a representative water sample, according
to an appropriate sampling design. During the whole procedure, cross-contamination and sample
contamination are avoided and eDNA integrity is maintained.
An overview on the key steps and considerations for the sampling, capture, and preservation of eDNA from
water is shown in Figure 1Figure 1.
Pre-field prepara�on
Sampling report (8)
Equipment and preserva�ves (6, 7)
Decontamina�on of equipment (9)
Sampling
Contamina�on precau�ons (9)
Key informa�onand field protocol (5)
No
Filtering on site Filtering off site
Preserving the sample (5.5)
Yes
Time un�l filtering the sample
depends on preserva�on method
No
Open filtering
Enclosed/housed filtering
field blank mandatoryfor filtering on site
field blankrecommended
field blankrecommended for filtering
off site
Yes
DNA preserva�on
solu�on, freeze or dry (5.5), IPC recommended
Transport and storage condi�on (5.5)

NOTE Numbers in parentheses refer to the respective clause or subclause.
Figure 1— Key steps and considerations for the eDNA water sampling process
5 Procedure
5.1 General
Water should be sampled to capture and separate eDNA via filtration, centrifugation or gravity filtration. The
[15][14]
probability of obtaining eDNA from the targeted organism(s) is positively correlated with ::
— the optimum sampling location and time point (including season) with regard to the organism(s) eDNA
[16] ][[17]
shedding rates, abundances (also of non-target organisms) including spawning time, , ([15][16])
metabolic activity and locomotion;
— the volume of water filtered;
— the spatial representativeness of the samples;
— the number of samples per water body.
5.2 Considerations prior to fieldwork
Depending on the different applications or goals of each eDNA survey, the most appropriate sampling
conditions and design shall be assessed based on case-by-case evidence to obtain water samples
representative of the water body and the organisms being monitored. These can include hydrological,
meteorological, seasonal or temporal, biological or ecological, and physiological variation.
This is particularly important in lentic (non-flowing) water bodies since eDNA is often unevenly distributed
[18][17][18] ][[19]
when the water is not well mixed. . Representative sampling can be achieved by merging (i.e.
pooling) subsamples collected at different points in the water body, or alternatively by continuous sampling
systems that move across the water body while drawing up water. When surveying deep water bodies and
targeting deep water dwelling organisms, water should be sampled from relevant depths (e.g. with Niskin
samplers; for decontamination processes, see Clause 9Clause 9).).
The following shall be considered when planning where and when to collect samples and subsamples:
— Features of the water body, including its size, depth, flow, stratification and the distribution of
microhabitats as well as inlets and outlets of the water body. If the study requires separate analyses of
subsamples (for examplee.g. biota in different depth layers), new or clean collection vessels shall be used
for each subsample.
— Biology of all target taxa, including habitat preferences, lifecyclelife cycle and (if known) DNA shedding
[20][19][20] ][[21]
rates. . Detection probability for individual species can be increased by timing sampling to
coincide with times of intense activity (e.g. spawning). Temporal variations in the amounts of released
eDNA by the target species needs to be considered. It is also important to consider whether target taxa are
likely to be present in the water body at the time of sampling.
NOTE Pooling of samples maycan lead to a decreased chance of detecting rare targets.
5.3 Equipment preparation prior to fieldwork
Prior to fieldwork a sufficient number of collecting vessels and equipment shall be cleaned to avoid
contamination (for detailed instruction, see Clause 9Clause 9).).
5.4 Sampling the eDNA from water
Various systems are used for sampling and filtering water. Some involve initially gathering water into a
collecting vessel where it is mixed and then filtered subsequently; other systems filter the water directly as it
is drawn up from the water body. When the water is not filtered directly in the water body, the filtration can
be carried out on the shore, on boats, or in the laboratory.
eDNA, tissue fragments, cells, and (in case of microbial communities) whole organisms shall be separated from
the collected water via filtration or other processes (e.g. including gravity filtration and centrifugation). This
maycan be achieved manually with syringes or using a hand or powered pump or by gravity filtration or
centrifugation, where it has been demonstrated to work. If a pump is used and water passes through a pump
tubing before reaching a filter, then a new or decontaminated pump tubing shall be used for each sample.
If subsamples are being merged into a pooled sample, ensure that they are well mixed before starting to filter.
When sampling eDNA, precaution measures shall be considered to avoid contamination (for detailed
instruction, see Clause 9Clause 9).).
5.5 Preserving the sample
5.5.1 General
The eDNA contained in the collected water should be separated from the water immediately in the field. Note
that DNA breakdown will occur when it is not possible to immediately separate and preserve the collected
water sample on-site. The rate at which this breakdown occurs, depends on several parameters such as
chemical composition of the collected water, storage conditions of the water sample, exposure to sunlight (e.g.
UV), as well as the type of organism releasing the eDNA. In general, the longer the period between collection
and preservation, the more eDNA will be broken down. Note that at room temperature, large amounts of target
eDNA can be lost within 12 h to 24 h. When it is not possible to separate the eDNA from the water on-site, then
[22][21]
separation should be undertaken as soon as possible (usually no longer than 6 hours unless a
preservation method is used to elongate the storage period (see e.g. Reference [23] [22]).). Water shall be
stored ≤ ≤ 8 °C and protected from UV light prior to separating eDNA from the collected water by filtration or
centrifugation. The obtained eDNA sample (e.g. filter, centrifuged pellet) shall be immediately preserved in
the field for transportation to the laboratory and storage prior to eDNA extraction. In case the eDNA collected
on a filter membrane has to be preserved (i.e. is not directly used for lysis), the membrane shall be either
completely covered by preservation solution or be frozen (≤ −(≤−18 °C), or both, or desiccated, depending on
filter type and manufacturer’s recommendation. Maximum storage time of filters depends on the DNA
preservation method used.
If a preservative solution is used, the solution used shall be clearly recorded because downstream laboratory
protocols for DNA extraction may need to be modified according to the preservative solution used. If freezing
is used for preservation, the filter membrane should either be frozen immediately after filtration is completed
or kept at 5± °C ± 3 °C no longer than 3 hoursh (part of the 6 hours h mentioned before) and protected from
UV light. Once the filter is frozen, it should remain continuously so until DNA extraction begins.
An IPC should be added before preserving filter samples to allow for monitoring eDNA degradation during
transport and storage of the sample. It is recommended to include an IPC in the preservative solution that can
be quantified after storage and DNA extraction using a quantitative PCR assay (e.g. quantitative PCR or digital
droplet PCR) to track sample degradation. If using freezing or drying and also using an IPC, add the IPC to the
filter membrane with the lysis buffer during the first phase of the DNA extraction and this will serve only as
an indication of successful DNA extraction; it will not serve as a degradation control.
Additional requirements for different filter types are mentioned 5.5.2 to 5.5.4below.
NOTE DependingThe obtained type of eDNA depends on the preservation method, the obtained type of eDNA will
differ: while. While freezing the samples will breakbreaks up the cells and releaseswhich release the intracellular DNA
therein, other preservation methods without freezing and depending on the type of preservation liquid used, will
preserve the extracellular eDNA which then can be separately extracted from the intracellular DNA contained in cells and
tissues. For further information on the preservation and extraction of different eDNA fractions, see Reference [24] [23].
5.5.2 Preserving eDNA in enclosed filters
If using an enclosed filter and a preservative solution, the filter unit shall be securely sealed to ensure that the
preservative solution fully covers the filter membrane throughout transportation and storage of the filter until
such time as DNA extraction begins. The temperature of the filter should be subjected to the previously
recommended temperature during transport and storage until DNA extraction, depending on the type of
preservative solution used.
If the filter cases are cracked in the laboratory (not recommended), they should be processed as housed filters
regarding contamination risk.
5.5.3 Preserving eDNA in open filters
If using an open filter, care shall be taken to not contaminate the sample. FilterHandling of the filter membrane
handling shall be performeddone using decontaminated tweezers.
NOTE Transferring the filter carries a risk of contamination.
If drying is used for preservation, then the filter membrane shall be sealed inside a DNA-free, air-proof
container along with a suitable drying agent until DNA extraction begins.
5.5.4 Preserving eDNA in housed filters
If using a housed filter, that is opened in the field, care shall be taken not to contaminateavoid contaminating
the samples. Preservative solutions can be added directly to the filter membrane inside the housing and
transported to the laboratory depending on the manufacturer. Filter membrane handling (if needed) shall be
performed using decontaminated tweezers.
NOTE Transferring the filter carries a risk of contamination.
The filter membrane shall be sealed inside a DNA-free, air-proof container.
If the housing is closed during preservation one shall follow the instructions for enclosed filters (see
5.5.25.5.2).).
If the filter is removed from the housing in the field and transferred to a test tube one shall follow to the
instructions for open filters (see 5.5.35.5.3).).
6 Equipment and its use
The specific type of equipment needed depends on the environment to be sampled and on the sampling
protocol. All equipment and materials used during field sampling need to be target DNA-free. Despite the need
for employing single-use materials to avoid contamination of samples, plastic waste should be minimized due
to environmental considerations as far as possible and reusable or recyclable items (e.g. buckets, syringes,
filter capsules) used wherever possible.
6.1 6.1 Gloves.
Wear fresh single-use target DNA-free gloves to avoid cross-contamination of samples.
— — at each sampling location during collection of samples by hand in the field,
— — for each new sample from a single location processed by open filtration in case contamination of the
sample containers cannot be avoided (e.g.,. water bottles in contact with river water and not cleaned
afterwards), and
— — whenever there is risk that they have become contaminated (e.g. touched a dirty surface).
6.2 6.2 Further equipment.
Equipment to reach the water to be sampled, e.g.for example a stick or a pole (expendable)), can be used to
collect water from difficult to reach sampling locations (for contamination avoidance, see Clause 9section 9).).
6.3 6.3 Bucket lined with target DNA-free, single-use plastic bag, to either collect samples or
to mix replicate samples, or both, of the same water body or sampling location.
6.4 6.4 Syringes
6.56.4 Target DNA-free syringes (as by manufacturer’s specifications), e.g. 50 ml to 300 ml, used to
manually press water through f
...

PROJET
Norme
internationale
ISO/DIS 17805.2
ISO/TC 147/SC 5
Qualité de l'eau — Échantillonnage,
Secrétariat: DIN
collecte et conservation de l’ADN
Début de vote:
environnemental prélevé dans l’eau
2025-02-04
Water quality — Sampling, capture and preservation of
Vote clos le:
environmental DNA from water
2025-04-01
ICS: 13.060.70
CE DOCUMENT EST UN PROJET DIFFUSÉ
POUR OBSERVATIONS ET APPROBATION. IL
EST DONC SUSCEPTIBLE DE MODIFICATION
ET NE PEUT ÊTRE CITÉ COMME NORME
INTERNATIONALE AVANT SA PUBLICATION EN
TANT QUE TELLE.
Le présent document est distribué tel qu’il est parvenu du secrétariat
du comité. OUTRE LE FAIT D’ÊTRE EXAMINÉS POUR
ÉTABLIR S’ILS SONT ACCEPTABLES À DES
FINS INDUSTRIELLES, TECHNOLOGIQUES ET
COMMERCIALES, AINSI QUE DU POINT DE VUE
DES UTILISATEURS, LES PROJETS DE NORMES
INTERNATIONALES DOIVENT PARFOIS ÊTRE
TRAITEMENT PARALLÈLE ISO/CEN
CONSIDÉRÉS DU POINT DE VUE DE LEUR
POSSIBILITÉ DE DEVENIR DES NORMES
POUVANT SERVIR DE RÉFÉRENCE DANS LA
RÉGLEMENTATION NATIONALE.
LES DESTINATAIRES DU PRÉSENT PROJET
SONT INVITÉS À PRÉSENTER, AVEC LEURS
OBSERVATIONS, NOTIFICATION DES DROITS
DE PROPRIÉTÉ DONT ILS AURAIENT
ÉVENTUELLEMENT CONNAISSANCE
ET À FOURNIR UNE DOCUMENTATION
EXPLICATIVE.
Numéro de référence
ISO/DIS 17805.2:2025(fr)
ISO/TC 147/SC 5
ISO/DIS 17805.2:2025(fr)
ƒ–‡ǣʹͲʹͷǦͲʹǦͲͶ
ISO/DIS 17805.2
‡…”±–ƒ”‹ƒ–ǣ
Qualité de l'eau — Échantillonnage, collecte et conservation de l’ADN
environnemental prélevé dans l’eau
Water quality — Sampling, capture and preservation of environmental DNA from water

Avertissement
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•—•…‡’–‹„Ž‡†‡‘†‹ˆ‹…ƒ–‹‘•ƒ•’”±ƒ˜‹•‡–‡’‡—–²–”‡…‹–±…‘‡‘”‡‹–‡”ƒ–‹‘ƒŽ‡Ǥ
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DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2025
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette
publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,
y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut
être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
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Publié en Suisse
ii
ISO/DIS 17805.2:2025(fr)
Sommaire Page
Avant-propos européen . iv
Introduction . v
1 Domaine d'application .1
2 Références normatives .1
3 Termes et définitions .1
4 Principe .3
5 Mode opératoire.5
5.1 Généralités .5
5.2 Éléments à prendre en compte avant le travail de terrain .6
5.3 Préparation du matériel avant le travail de terrain .6
5.4 Échantillonnage de l’ADNe dans l’eau .6
5.5 Conservation de l’échantillon.7
5.5.1 Généralités .7
5.5.2 Conservation de l’ADNe dans des filtres fermés .7
5.5.3 Conservation de l’ADNe dans des filtres ouverts .8
5.5.4 Conservation de l’ADNe dans des filtres enclavés .8
6 Matériel .8
7 Solutions de conservation . 10
7.1 Généralités . 10
7.2 Exemples de solutions de conservation . 10
8 Rapport d’échantillonnage . 10
8.1 Généralités . 10
8.2 Identité et caractéristiques de l’échantillon . 11
8.3 Site d’échantillonnage . 11
8.4 Conditions d’échantillonnage . 11
8.5 Échantillonnage . 12
9 Prévention de la contamination des échantillons . 12
9.1 Généralités . 12
9.2 Prévention de la contamination . 12
9.2.1 Contamination introduite par le matériel . 12
9.2.2 Contamination introduite par la personne prélevant les échantillons . 12
9.3 Mode opératoire de décontamination du matériel d’échantillonnage . 13
9.3.1 Généralités . 13
9.3.2 Matériel et équipement en contact direct avec l’échantillon d’eau . 13
9.3.3 Matériel et équipement qui ne sont pas en contact direct avec l’échantillon d’eau . 13
Annexe A (informative) Types de filtres. 14
Bibliographie . 15

iii
ISO/DIS 17805.2:2025(fr)
Avant-propos européen
Le présent document (FprEN 17805 :2022) a été élaboré par le comité technique CEN/TC 230 « Analyse
de l’eau », dont le secrétariat est tenu par DIN.
Ce document est actuellement soumis au Vote Formel.
Il convient que l’utilisateur adresse tout retour d’information et toute question concernant le présent
document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes
se trouve sur le site web du CEN.
iv
ISO/DIS 17805.2:2025(fr)
Introduction
AVERTISSEMENT — Il convient que les personnes utilisant le présent document connaissent les
protocoles d’échantillonnage de l’eau pour évaluer la diversité biologique. Le présent document
n’a pas pour but de traiter tous les problèmes de sécurité qui sont, le cas échéant, liés à son
utilisation. Il incombe à l’utilisateur d’établir des pratiques d’hygiène et de sécurité appropriées.
De plus, le besoin de notification, d’obtention de certificats ou d’autorisations mis avant
l'échantillonnage, selon les lois et réglementations nationales ou internationales telles que le
Protocole de Nagoya sur l’accès aux ressources génétiques (https://www.cbd.int/abs/), doit être
pris en compte.
La surveillance des organismes est essentielle pour évaluer l’état des écosystèmes aquatiques et est
requise par la législation nationale et internationale telle que la directive-cadre sur l’eau de l’Union
européenne (2000/60/CE). Plusieurs méthodes de surveillance des organismes dans les milieux
aquatiques ont été décrites, ce qui a conduit à l’élaboration d’une vaste gamme de Normes européennes
(par exemple EN 14011 :2003, EN 14757 :2005, EN 15460 :2007). Toutefois, ces approches nécessitent
de capturer et/ou collecter les organismes concernés, ce qui peut être un processus laborieux et
chronophage.
La possibilité de détecter la présence d’organismes et/ou de quantifier leur abondance relative (par
[6]
exemple ) dans les milieux aquatiques par l’analyse de l’ADN environnemental (ADNe) offre un nouveau
moyen de surveiller la biodiversité dans divers groupes taxonomiques, notamment les micro-organismes,
[7][8][9]
les plantes et les animaux ( ). Cette approche permet d’étudier la diversité des organismes sans avoir
directement besoin de les isoler et de les capturer. De plus, elle est supposée jouer un rôle majeur dans
de futures biosurveillances, qui auraient pour objectif d’inventorier des espèces avec une haute
[10]
résolution temporelle et spatiale . Bien que la performance de l’approche ADNe ait été rapportée à
[11]
plusieurs reprises , il est fortement nécessaire de standardiser l’évaluation de la biodiversité aquatique
[12][13]
utilisant l’approche ADNe ( ). Il faut cependant noter que la biosurveillance fondée sur l’ADNe ne
permet pas d’obtenir certains paramètres de la population (par exemple, taille des individus, sexe) qui
peuvent être obtenus avec des techniques d’échantillonnage classiques.
Le présent document fournit des recommandations sur la façon de collecter et de conserver l’ADNe à
partir d'échantillons d’eau, abordant la première étape, cruciale, pour toutes analyses ultérieures de la
biodiversité fondées sur l’ADNe. Un rapport technique spécifique pour l'échantillonnage en routine de
diatomées benthiques dans les rivières et les plans d’eau adapté aux analyses de type metabarcoding, est
le CEN/TR 17245:2018.
Dans le présent document, les formes verbales suivantes sont utilisées pour spécifier les modes
opératoires de travail :
— « doit » indique une exigence ;
— « il convient de/que » indique une recommandation ;
— « peut/il est admis/permis » indique une autorisation ;
— « peut/il est possible que » indique une possibilité ou une capacité.

v
PROJET DE NORME INTERNATIONALE ISO/DIS 17805.2:2025(fr)

Qualité de l'eau — Échantillonnage, collecte et conservation de
l’ADN environnemental prélevé dans l’eau
1 Domaine d'application
Le présent document spécifie des modes opératoires d'échantillonnage, de capture et de conservation de
l’ADN environnemental (ADNe) dans des milieux aquatiques, provenant d’organismes qui sont ou qui ont
été récemment présents dans une masse d’eau, qui l’ont parcouru ou dont l’ADN a été introduit dans la
masse d’eau par un mécanisme précis. Le présent document porte également sur les modes opératoires
permettant d'éviter la contamination des échantillons et de contrôler la qualité de l’ADN, sur les
principales propriétés du mode opératoire et du matériel de filtration et sur les normes relatives au
compte rendu
Le présent document n’inclut ni la collecte d’ADNe à partir de biofilms, de sédiments ou d’autres types
d'échantillons similaires ni les méthodes d’échantillonnage passif, et n’aborde pas la question des plans
d'échantillonnage.
2 Références normatives
Le présent document ne contient aucune référence normative.
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions suivants s’appliquent.
L’ISO et l’IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en
normalisation, consultables aux adresses suivantes :
— IEC Electropedia : disponible à l’adresse https://www.electropedia.org/
— ISO Online browsing platform : disponible à l’adresse https://www.iso.org/obp
3.1
contamination croisée
transfert involontaire de toute nature et/ou d’ADN d’un échantillon à un autre
3.2
décontamination
mode opératoire consistant à éliminer toute source et/ou trace d’ADN du matériel pouvant entrer en
contact avec l’échantillon
3.3
filtre fermé
système de filtration dans lequel la membrane filtrante est intégrée et pour lequel l'orifice d’entrée et
l’orifice de sortie peuvent être fermés pendant le transport et le stockage
Note 1 à l’article : L’ADNe contenu sur le filtre est généralement extrait sans sortir la membrane de la cartouche
filtrante, ce qui réduit nettement le risque de contamination des échantillons. Voir Figure A.1 C. à l’Annexe A.
ISO/DIS 17805.2:2025(fr)
3.4
ADN environnemental
ADNe
matériel provenant d’organismes morts ou vivants, notamment fragments d’ADN simple brin (sb) ou
double brin (db) provenant d’ADN nucléaire ou mitochondrial/plastidial d’eucaryotes ainsi que d’ADN
plasmidique ou chromosomique de procaryotes
Note 1 à l’article : Est inclus l’ADN de diverses sources telles que les organismes unicellulaires et les petits
organismes multicellulaires ou les particules de tissus (par exemple, cellules désagrégées, matières fécales) et les
gamètes d’organismes multicellulaires.
3.5
blanc de matériel de terrain
échantillon obtenu par traitement d’eau exempte d’ADN cible (par exemple, eau distillée) dans tout le
matériel utilisé et suivant tous les modes opératoires impliqués dans le processus d'échantillonnage
d’ADNe pour s’assurer que le matériel et les modes opératoires n’introduisent pas de contamination
3.6
filtre enclavé
système dans lequel une membrane filtrante est protégée à l’intérieur d’un boîtier solide pendant le
processus de filtration, qui est ensuite ouvert pour retirer la membrane filtrante pour la suite des
traitements
Note 1 à l’article : Les filtres sont retirés du boîtier pour extraire l’ADNe. Le boîtier peut être ouvert et le filtre retiré
en vue du stockage et d’un traitement ultérieur. Voir Figure A.1 B. à l’Annexe A.
3.7
tampon de lyse
solution tampon servant à conserver l’ADN présent dans l’échantillon et à lyser/ouvrir les cellules comme
première étape de l’extraction de l’ADN
3.8
témoin interne positif
TIP
quantité définie d’ADN synthétique ou naturel contenant une séquence amplifiable par PCR qui ne sera
pas naturellement présente dans l'échantillon, utilisée pour différencier les types de résultats négatifs
(aucune séquence cible versus inhibition de la PCR)
Note 1 à l’article : Le TIP peut être ajouté à l’échantillon ou au tampon de conservation/lyse à une concentration
connue pour vérifier les efficacités de conservation, d’extraction, d’amplification et d’identification de l’ADN.
3.9
filtre ouvert
système de filtration, y compris les unités de filtration sous vide (laboratoire) et les sacs à dos de filtration
(terrain), duquel la membrane filtrante doit être retirée à l’aide de pinces pour la suite des traitements
Note 1 à l’article : Voir Figure A.1 A. à l’Annexe A.
3.10
pré-filtre
membrane filtrante, maille ou crépine ayant une taille de pore supérieure à celle de la membrane du filtre
principal (utilisée pour collecter l’ADNe) à travers laquelle l’eau est d’abord introduite pour éliminer les
grosses particules de sédiment, de matière végétale ou d’algues, utilisée pour augmenter le volume d’eau
qui peut être filtré avant saturation du filtre principal
ISO/DIS 17805.2:2025(fr)
3.11
contamination de l’échantillon
processus par lequel de l’ADN exogène est accidentellement introduit dans l’échantillon
Note 1 à l’article : L’ADN déjà présent dans l’eau avant l’échantillonnage de l’ADNe n’est pas considéré comme une
source de contamination.
3.12
ADN cible
toute source et/ou trace d’ADN provenant de l’espèce/du taxon étudié
3.13
filtre fermé
système de filtration dans lequel une membrane filtrante est protégée à l’intérieur d’un boîtier solide
pendant la filtration et la suite des traitements, par exemple la lyse ; il n’est pas ouvert, ce qui réduit au
minimum la contamination de l'échantillon
Note 1 à l’article : Voir Figure A.1 C. à l’Annexe A.
4 Principe
Un échantillon d’eau représentatif de la masse d’eau étudiée est prélevé conformément à un plan
d'échantillonnage approprié pour collecter et séparer l’ADNe de l’échantillon d’eau. Pendant l’ensemble
du mode opératoire, la contamination croisée et la contamination de l'échantillon sont évitées et
l’intégrité de l’ADNe est assurée.
Une vue d’ensemble des principales étapes et considérations applicables à l'échantillonnage, la collecte
et la conservation de l’ADNe présent dans l’eau est fournie à la Figure 1.
ISO/DIS 17805.2:2025(fr)
ISO/DIS 17805.2:2025(fr)
Pre-field preparation: Préparation avant l’arrivée sur le terrain :
Sampling design (8) Plan d’échantillonnage (8)
Equipment and preservatives (6, 7) Matériel et solutions de conservation (6, 7)
Decontamination of equipment (9) Décontamination du matériel (9)
Sampling Échantillonnage
Contamination precautions (9) Précautions relatives à la contamination (9)
Key information and field protocol (8) Informations principales and protocole de
terrain (8)
Filtering on site Filtration sur site
Yes Oui
No Non
Filtering off site Filtration hors site
Preserving the sample (5.5) Conservation de l’échantillon (5.5)
Time until filtering sample depends on Le délai entre la collecte et la filtration de
preservation method l’échantillon dépend de la méthode de
conservation
Enclosed filtering Filtre fermé
Housed/Open filtering Filtre enclavé/ouvert
Field equipment blank mandatory Blanc de matériel de terrain obligatoire
eDNA preservation Conservation de l’ADNe
solution, freeze or dry (5.5), IPC recommended Solution tampon, congélation ou séchage (5.5),
CIP recommandé
Transport and storage condition (5.5) Conditions de transport et de stockage (5.5)
NOTE Les chiffres entre parenthèses font référence à l’article/au paragraphe correspondant.
Figure 1 —Principales étapes et considérations applicables au processus d'échantillonnage de
l’ADNe présent dans l’eau
5 Mode opératoire
5.1 Généralités
Il convient de prélever de l’eau pour collecter et séparer l’ADNe par filtration ou par d’autres processus.
La probabilité d’obtenir l’ADNe du ou des organismes cibles est corrélée positivement avec :
— le nombre d’échantillons par masse d’eau ;
ISO/DIS 17805.2:2025(fr)
— la représentativité spatiale des échantillons ;
— le volume d’eau filtré ;
— le moment optimal/la saison optimale d'échantillonnage vis-à-vis du taux d’excrétion d’ADNe par le
ou les organismes, de leurs abondances (y compris celles des organismes non cibles), tenant compte
[15] [16]
de la période de frai ( ), de leur activité métabolique et de leurs déplacements.
5.2 Éléments à prendre en compte avant le travail de terrain
Selon les applications/objectifs de chaque analyse ADNe, les conditions et le plan d'échantillonnage
optimaux doivent être évalués au cas par cas pour obtenir des échantillons d’eau représentatifs de la
masse d’eau et des organismes surveillés. Cela peut comprendre les variations hydrologiques,
météorologiques, saisonnières/temporelles, biologiques/écologiques et physiologiques.
Ce point est particulièrement important pour les masses d’eau lentiques (stagnantes) car l’ADNe est
souvent inégalement réparti lorsque l’eau n’est pas bien mélangée. Un échantillonnage représentatif peut
être obtenu en combinant des sous-échantillons collectés à différents points de la masse d’eau, ou en
utilisant des systèmes d'échantillonnage continu qui se déplacent dans la masse d’eau tout en aspirant de
l’eau. Lors de l'étude de masses d’eaux profondes ciblant des organismes vivant en eaux profondes, il peut
être nécessaire de prélever de l’eau en profondeur.
Pour maximiser la probabilité de capturer de l’ADN cible, les points suivants doivent être pris en compte
lors du choix du lieu et du moment où les échantillons et sous-échantillons seront collectés :
1) Caractéristiques de la masse d’eau, y compris sa taille, sa profondeur, son débit, ainsi que sa
stratification et la répartition des microhabitats ainsi que les entrées/sorties de la masse d’eau. Si
l’étude requiert des analyses distinctes de sous-échantillons (par exemple, du biote provenant de
couches de différente profondeur), des récipients de collecte neufs ou propres doivent être utilisés
pour chaque sous-échantillon.
2) Biologie de tous les taxons cibles, y compris les préférences d’habitats et le cycle de vie. La probabilité
de détection des espèces individuelles peut être améliorée en faisant coïncider l'échantillonnage avec
les périodes d’activité intense (par exemple la reproduction). Les variations temporelles des
quantités d’ADNe libéré par les espèces cibles doivent être prises en compte. Il est également
important de s’interroger si les taxons cibles ont des chances d’être présents dans la masse d’eau au
moment de l’échantillonnage, notamment dans le cas d’espèces amphibies ou migratrices (diurnes).
5.3 Préparation du matériel avant le travail de terrain
Avant le travail de terrain, un nombre suffisant de récipients et d’équipements de collecte doivent être
nettoyés pour éviter toute contamination (pour des instructions détaillées, voir l’Article 9).
5.4 Échantillonnage de l’ADNe dans l’eau
Divers systèmes sont utilisés pour prélever et filtrer l’eau. Certains impliquent la collecte initiale d’eau
dans un récipient dans lequel l’eau est mélangée puis filtrée ; d’autres systèmes filtrent l’eau directement
lorsqu’elle est prélevée de la masse d’eau. Lorsque l’eau n’est pas filtrée directement dans la masse d’eau,
la filtration peut être effectuée sur la berge ou en laboratoire.
L’eau doit être prélevée et/ou filtrée pour collecter les fragments de tissus, les cellules et l’ADN. Cela peut
être fait manuellement à l’aide de seringues, au moyen d’une pompe à main ou à commande mécanique
ou par filtration gravitaire/centrifugation, si cette technique s’est révélée efficace. Si une pompe est
utilisée et que l’eau traverse un tube avant d’atteindre un filtre, alors un nouveau tube ou un tube
décontaminé doit être utilisé pour chaque échantillon.
ISO/DIS 17805.2:2025(fr)
En cas de regroupement de sous-échantillons en un échantillon combiné, vérifier que les sous-
échantillons sont correctement mélangés avant de commencer à filtrer.
Lors de l’échantillonnage d’ADNe, des mesures de précaution doivent être prises (pour des instructions
détaillées, voir l’Article 9).
5.5 Conservation de l’échantillon
5.5.1 Généralités
Idéalement, il convient de séparer l’eau et l’ADNe contenu dans l’eau collectée immédiatement sur le
terrain, et de conserver l’échantillon d’ADNe obtenu immédiatement sur le terrain (par exemple, filtre,
précipité, culot centrifugé) en vue du transport au laboratoire et du stockage avant l’extraction d’ADNe.
Noter qu’une dégradation de l’ADN se produira s’il est impossible de séparer et conserver
immédiatement sur le terrain l'échantillon d’eau collecté. Le taux de dégradation dépend de plusieurs
paramètres tels que la composition chimique et physique de l’eau collectée, les conditions de stockage de
l’échantillon d’eau, l’exposition à la lumière du soleil (par exemple UV) ainsi que le type d’organismes
contribuant à l’ADNe. En général, plus la durée entre la collecte et la conservation est longue, plus la
quantité d’ADNe dégradé sera élevée. Note
...