oSIST prEN ISO 23611-6:2025

SLOVENSKI STANDARD
01-september-2025
Kakovost tal - Vzorčenje nevretenčarjev v tleh - 6. del: Navodilo za pripravo
programov vzorčenja nevretenčarjev v tleh (ISO/DIS 23611-6:2025)
Soil quality - Sampling of soil invertebrates - Part 6: Guidance for the design of sampling
programmes with soil invertebrates (ISO/DIS 23611-6:2025)
Bodenbeschaffenheit - Probenahme von Wirbellosen im Boden – Teil 6: Anleitung für die
Planung der Probenahme von Wirbellosen im Boden (ISO/DIS 23611-6:2025)
Qualité du sol - Prélèvement des invertébrés du sol - Partie 6: Lignes directrices pour la
conception de programmes d'échantillonnage des invertébrés du sol (ISO/DIS 23611-
6:2025)
Ta slovenski standard je istoveten z: prEN ISO 23611-6
ICS:
13.080.30 Biološke lastnosti tal Biological properties of soils
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 23611-6
ISO/TC 190/SC 4
Soil quality — Sampling of soil
Secretariat: AFNOR
invertebrates —
Voting begins on:
Part 6: 2025-08-06
Guidance for the design of sampling
Voting terminates on:
2025-10-29
programmes with soil invertebrates
Qualité du sol — Prélèvement des invertébrés du sol —
Partie 6: Lignes directrices pour la conception de programmes
d'échantillonnage des invertébrés du sol
ICS: 13.080.30
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Reference number
ISO/DIS 23611-6:2025(en)
DRAFT
ISO/DIS 23611-6:2025(en)
International
Standard
ISO/DIS 23611-6
ISO/TC 190/SC 4
Soil quality — Sampling of soil
Secretariat: AFNOR
invertebrates —
Voting begins on:
Part 6:
Guidance for the design of sampling
Voting terminates on:
programmes with soil invertebrates
Qualité du sol — Prélèvement des invertébrés du sol —
Partie 6: Lignes directrices pour la conception de programmes
d'échantillonnage des invertébrés du sol
ICS: 13.080.30
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
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Published in Switzerland Reference number
ISO/DIS 23611-6:2025(en)
ii
ISO/DIS 23611-6:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
3.1 Soil biology .2
3.2 Soil protection .3
3.3 Methods .4
4 Principle . 4
4.1 General .4
4.2 Question to be answered when planning a field study .5
5 Objectives of sampling . 6
5.1 General .6
5.2 General remarks .6
5.3 Pre-conditions . .7
5.4 The performance of the site-specific assessment of contaminated land .7
5.5 The study of potential side effects of anthropogenic impacts .7
5.6 The biological classification and assessment of soils in order to determine the biological
quality of soils .8
5.7 Biogeographical monitoring in nature protection or restoration .8
6 Samples and sampling points . 8
6.1 General .8
6.2 Sampling patterns .8
6.3 Selecting and identifying the sampling location .9
6.4 Preparation of the sampling site .10
6.5 Further general advice on sampling performance .10
7 Practical considerations for the biological sampling of soils .10
7.1 General .10
7.2 Formal preparations.10
7.3 Requirements on sampling personnel and safety precautions .11
7.4 Preliminary survey . .11
7.4.1 General .11
7.4.2 Desk-top study .11
7.4.3 Visiting the site .11
7.5 Main study . 12
8 Design options for sampling soil invertebrates .13
8.1 Introduction . 13
8.2 Description of possible sampling strategies .14
8.3 Recommendations from the European programme ENVASSO (Environmental
Assessment of Soil for Monitoring) .14
9 Sampling report .16
10 Quality assurance and quality control (QA/QC) . 17
Bibliography .18

iii
ISO/DIS 23611-6:2025(en)
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,
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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 documents 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)
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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 190, Soil quality, Subcommittee SC 4, Biological
characterization, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 444, Environmental characterization of solid matrices, in accordance with the Agreement
on technical cooperation between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 23611-6:2012), which has been technically
revised.
The main changes are:
— addition of detailed recommendations about the statistical methods that shall be applied in site-specific
risk assessment of contaminated land in section 7.5
— removal of the informative annex A with examples of case studies.
A list of all parts in the ISO 23611 series can be found on the ISO website.
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
ISO/DIS 23611-6:2025(en)
Introduction
The biodiversity of soil fauna is tremendous. Soil harbours species-rich communities, which regulate
ecosystem processes such as organic matter decomposition, nutrient flows or soil fertility in general,
References [1], [2]. All terrestrial animal phyla can be found in soils, Reference [3]. In addition to thousands
of bacterial and fungal “species”, more than 1 000 species of invertebrates in abundances of up to 1,5 million
individuals can be found within a square metre of soil, References [4], [5]. This diversity can only be reliably
estimated by investigation of the soil community itself, since other parameters like climate are not or only
weakly correlated with species richness, Reference [6].
The composition of this community, as well as the abundance and biomass of the individual species and
groups is a valuable source of information, since they integrate various abiotic and biotic effects such as soil
properties and conditions, climate, competition or biogeographical influences, Reference [7]. For this reason,
the evaluation of the biodiversity of soil invertebrate communities becomes more and more important for
the classification and assessment of biological soil quality, Reference [8]. However, this work is only possible
if data collection (i.e. sampling of the soil fauna) is carried out according to standardized methods. For this
reason, a number of ISO guidelines have been prepared covering the sampling of the most important soil
organism groups.
In the individual parts of ISO 23611, the practical work concerning the respective animal group is described
in detail. However, (nearly) nothing is said about how to plan the use of such methods or how to evaluate
the results. Despite the fact that sampling for any field study can be different depending on the individual
purpose, guidance is needed for monitoring studies in a legal context. Such studies can include the following:
— site-specific risk assessment of contaminated land;
— study of potential side effects of anthropogenic impacts (e.g. the application of chemicals or the building
of roads);
— the biological classification and assessment of soils in order to determine the biological quality of soils;
— long-term biogeographical monitoring in the context of nature protection or restoration, including global
change [e.g. as in long-term ecological research projects (LTERs)].
Spatial studies focusing on environmental and ecological questions require a carefully designed strategy for
collecting data. References [9], [10]. Before identifying the optimal design, two issues have to be clarified:
what is the objective of the study and what is already known about the survey area? Afterwards, one may
select one of the well-known design patterns (e.g. grid sampling, random sampling, clustered sampling
or random transects) or prepare a study-specific design. In any case, the field sampling design has to be
practical, e.g. the volume of soil to be sampled, depending on the size and distribution of the organisms, has
to be manageable (i.e. the smaller the individual animal, the smaller the size), and cost effective.
In studies focusing on soil invertebrates, it is not possible to observe the entire population. Therefore,
sampling is done only at a limited number of locations. The main reason for using statistical sound sampling
schemes is that such sampling guarantees scientific objectivity and avoids forms of bias such as those caused
by judgement sampling. This is especially valuable if the objective is to obtain data that are representative
for the whole area. At the same time, statistics-based sampling schemes ensure standardized sampling
methods over time, i.e. if the same area is to be re-sampled in the future, the results will be comparable.
The rationale for this guidance on the design of field sampling methods for soil invertebrates takes into
consideration the guidance provided in ISO 10381-1 describing soil sampling in general.
The design of microbiological studies is already covered by ISO 10381-6, ISO 14240-1 and ISO 14240-2.

v
DRAFT International Standard ISO/DIS 23611-6:2025(en)
Soil quality — Sampling of soil invertebrates —
Part 6:
Guidance for the design of sampling programmes with soil
invertebrates
1 Scope
This part of ISO 23611 provides guidance for the design of field studies with soil invertebrates (e.g. for the
monitoring of the quality of a soil as a habitat for organisms). Detailed information on the sampling of the
most important soil organisms is provided in the other parts of this International Standard (ISO 23611-1 to
ISO 23611-5).
This part of ISO 23611 is used for all terrestrial biotopes in which soil invertebrates occur. Basic information
on the design of field studies in general is already laid down in ISO 10381-1. This information can vary
according to the national requirements or the climatic/regional conditions of the site to be sampled.
NOTE While this part of ISO 23611 aims to be applicable globally for all terrestrial sites that are inhabited by
soil invertebrates, the existing information refers mostly to temperate regions. However, the (few) studies from other
(tropical and boreal) regions, as well as theoretical considerations, allow the conclusion that the principles laid down
in this part of ISO 23611 are generally valid, References [1], [11], [12], [13].
This part of ISO 23611 gives information on site-specific risk assessment of contaminated land, study of
potential side effects of anthropogenic impacts (e.g. the application of chemicals or the building of roads),
the biological classification and assessment of soils in order to determine the biological quality of soils, and
long-term biogeographical monitoring in the context of nature protection or restoration, including global
change (e.g. as in long-term ecological research 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 10390, Soil, treated biowaste and sludge – Determination of pH
ISO 10694, Soil quality — Determination of organic and total carbon after dry combustion (elementary analysis)
ISO 11074, Soil quality — Vocabulary
ISO 11260, Soil quality — Determination of effective cation exchange capacity and base saturation level using
barium chloride solution
ISO 11272, Soil quality — Determination of dry bulk density
ISO 11274, Soil quality — Determination of the water-retention characteristic — Laboratory methods
ISO 11277, Soil quality — Determination of particle size distribution in mineral soil material — Method by
sieving and sedimentation
ISO 11461, Soil quality — Determination of soil water content as a volume fraction using coring sleeves —
Gravimetric method
ISO 11465, Soil quality — Determination of dry matter and water content on a mass basis — Gravimetric method

ISO/DIS 23611-6:2025(en)
ISO 11466, Soil quality — Extraction of trace elements soluble in aqua regia
ISO 13878, Soil quality — Determination of total nitrogen content by dry combustion ("elemental analysis")
ISO 14869-1, Soil quality — Dissolution for the determination of total element content — Part 1: Dissolution
with hydrofluoric and perchloric acids
ISO 15709, Soil quality — Soil water and the unsaturated zone — Definitions, symbols and theory
ISO 15799, Soil quality — Guidance on the ecotoxicological characterization of soils and soil materials
ISO 17616, Soil quality — Guidance on the choice and evaluation of bioassays for ecotoxicological characterization
of soils and soil materials
ISO 18400-102, Soil quality — Sampling — Part 102: Selection and application of sampling techniques
ISO 18400-103, Soil quality — Sampling — Part 103: Safety
ISO 18400-104, Soil quality — Sampling — Part 104: Strategies
ISO 18400-202, Soil quality — Sampling — Part 202: Preliminary investigations
ISO 18400-203, Soil quality — Sampling — Part 203: Investigation of potentially contaminated sites
ISO 18400-206, Soil quality — Sampling — Part 206: Collection, handling and storage of soil under aerobic
conditions for the assessment of microbiological processes, biomass and diversity in the laboratory
ISO 23611-1, Soil quality — Sampling of soil invertebrates — Part 1: Hand-sorting and formalin extraction of
earthworms
ISO 23611-2, Soil quality — Sampling of soil invertebrates — Part 2: Sampling and extraction of micro-
arthropods (Collembola and Acarina)
ISO 23611-3, Soil quality — Sampling of soil invertebrates — Part 3: Sampling and extraction of enchytraeids
ISO 23611-4, Soil quality — Sampling of soil invertebrates — Part 4: Sampling, extraction and identification of
soil-inhabiting nematodes
ISO 23611-5, Soil quality — Sampling of soil invertebrates — Part 5: Sampling and extraction of soil macro-
invertebrates
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11074 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 Soil biology
3.1.1
biodiversity
variability among living organisms on the earth, including the variability within and between species, and
within and between ecosystems
Note 1 to entry: Also often used as the number and variety of organisms found within a specified geographic region.

ISO/DIS 23611-6:2025(en)
3.1.2
community
association of organisms, belonging to different species, families, etc. living at the same time at the same
place, i.e. the living portion of an ecosystem
[SOURCE: See Reference [14].]
3.1.3
invertebrate
metazoans (Kingdom Animalia or Metazoa) without backbone (spine). This is not a taxonomic classification,
but based on convenience and tradition”.
[SOURCE: See reference [15]]
3.1.4
microfauna, mesofauna and macrofauna
way of classifying the soil fauna (invertebrate animals) according to the size (length, diameter) of the
individual animals
EXAMPLE Important examples of the microfauna are water bears (Tardigrade), wheel animalcules (Rotifera) and
roundworms (Nematoda), for the mesofauna springtails (Collembola), mites (Acari) and potworms (Enchytraeid),
and for the macrofauna earthworms (Crassiclitelata), ants (Formicidae), beetles (Coleoptera), termites (Isoptera),
woodlice (Isopoda), millipedes (Chilopoda), centipedes (Diplopoda), spiders (Araneae) and snails (Gastropoda). Terms
like micro-arthropods and macro-arthropods are also used to refer to part of mesofauna and macrofauna respectively.
[SOURCE: See Reference [16].]
3.1.5
taxocoenosis
total number of species belonging to the same higher taxonomic unit (e.g. family, order) within a community
3.2 Soil protection
3.2.1
soil quality
capacity of a specific kind of soil to function, within natural or managed ecosystem boundaries, to sustain
plant and animal productivity, maintain or enhance water and air quality, and support human health and
habitation
Note 1 to entry: In more recent definitions, the natural functions of soil are specifically listed: soil as a habitat for
organisms, as part of natural systems with particular functions, as nutrient cycles, decomposition, retention and
filtration, Reference [12].
[SOURCE: See References [3], [17].]
3.2.2
habitat
sum of the environment of a particular species or community (e.g. in terms of soil properties, land use,
climate)
3.2.3
habitat function
ability of soils/soil materials to serve as a habitat for microorganisms, plants, and soil-living animals, and
support their interactions (community or biocenosis)
3.2.4
contamination
substance(s) or agent(s) present in the soil as a result of human activity
Note 1 to entry: There is no assumption in this definition that harm results from the presence of the contaminant.

ISO/DIS 23611-6:2025(en)
3.2.5
pollutant
substances which, due to their properties, amount or concentration, cause impacts on soil functions or soil use
3.2.6
reference soil
uncontaminated soil with comparable pedological properties to the soil being studied except that it is free of
contamination
3.3 Methods
3.3.1
Geographical Information Systems
GIS
in the strictest sense, a computer system capable of assembling, storing, manipulating, and displaying
geographically referenced information, i.e. data identified according to their locations
3.3.2
site-specific assessment
evaluation of the quality of a specific-site by using chemical, biological and/or physical methods
3.3.3
environmental risk assessment
process of identifying and quantifying risk (probability that an effect occurs) to non-human organisms and
determining the acceptability of these risks
3.3.4
soil function
role performed by soil that support ecosystems, the biosphere, the water environment and human activities
3.3.5
soil organism function
activity provided by individual species or, more often, by interaction of several species or the whole soil
community, e.g. nitrogen fixation, organic-matter breakdown or formation of soil structure
4 Principle
4.1 General
The design of field studies for the investigation of soil invertebrates differs significantly depending on the
respective aim. However, in all cases, it is necessary to take samples since the site and biological populations
to be studied are usually too large to be studied in total. In addition, most soil invertebrates live hidden
within the soil and/or are too small to be studied directly. The samples collected should be as representative
as possible of the site to be characterized but destruction should be kept at a minimum. In addition, the
occurrence of material not naturally belonging to the study site (e.g. waste or chemicals) can cause problems
when taking samples in multiphase systems such as soils, which contains water, gases, mineral solids and
biological material.
The study design (e.g. the position and density of sampling points, time of sampling, and the sampling
method) depends mainly on the objectives of the study and on the amount and quality of information
already available from the study site (e.g. historical data, personal experience). The design also depends on
whether information is needed as an average value (sampling for the spatial mean, e.g. the average number
of nematodes) or as a spatial distribution (e.g. sampling for a map showing nematode abundances in relation
to soil properties). In addition, the sheer size and the heterogeneity of soil properties, as well as those of the
organisms to be sampled shall be taken into consideration. In any case, a list of measurement end points
should be compiled for the respective organism group(s) and the main limitations of the sampling method(s)
shall also be known. The latter refers mainly to the high natural variability of invertebrate data. The normal
statistical tests used by those who take composite samples (microflora, soil properties) or many samples
(soil properties) which can be processed more or less automatically, cannot be applied here.

ISO/DIS 23611-6:2025(en)
Some consideration should also be given to the degree of detail and precision that is required and also the
manner in which the results are to be expressed (e.g. maximum and minimum values in a table, graphical
presentations or maps). Appropriate statistical methods for the evaluation of area-related data (including
the use of GIS methods) shall be identified as well. It can often be necessary to carry out an exploratory
sampling programme before the final study design can be defined in detail. The main points on which
decisions shall be made are listed in 4.2, reflecting the logical order of how to proceed a study.
NOTE This clause was written in close consideration with ISO 10381-1.
4.2 Question to be answered when planning a field study
The objective of a study can be established by the following questions:
— Why is such a study going to be performed?
— What information is necessary to answer the questions asked and how can this information be clearly
presented?
— Which approach is used for the interpretation of the results?
— How can the study outcome be tailored to the needs of the study sponsor (or stakeholder)?
The preliminary information can be defined by the following questions:
— What is already known about present and historical (especially land-use, management) site and soil
characteristics?
— What information is missing? Can it be made available?
— Who is to be contacted for certain (e.g. historical) sources?
— Are there any legal problems such as entering the sites?
— Shall other than biological parameters be measured at the same site and time, i.e. are (negative)
interactions of the various sampling programmes to be expected?
— Has the site been visited already?
The strategy of a study can be developed by the following questions:
— How are the delineations in time and space of the area(s) to be investigated determined?
— Which organism groups and measurement end points are appropriate to reach the study objective?
— Which sampling patterns, sampling points, sampling times, depths of sampling should be used?
— Can methods specified in International Standards be employed for all activities?
The decision on sampling and analysis can be made by answering the following questions:
— Can the sampling be done according to the respective International Standard or is there any deviation?
— How is the communication with the personnel responsible for sample presentation and analysis
coordinated?
— Which statistical evaluation methods are being employed?
— Does sampling correspond to later data analyses?
— Is it possible to address the right taxonomic level when studying the biological material?
— How is the documentation organized?

ISO/DIS 23611-6:2025(en)
The following questions on safety should be answered:
— Are all necessary safety precautions at that site considered?
— Is information concerning landowners, local authorities etc. secured?
— Are the requirements of ISO 10381-3, covering guidance on safety in sampling programmes, as well
as those safety issues listed in other parts of this International Standard (ISO 23611-1 to ISO 23611-5)
fulfilled?
The following questions on the sampling report should be answered:
— Is there any deviation from the basic content of a study report as specified in this part of ISO 23611?
— Is additional information required?
— How is it ensured that any later deviation from this part of ISO 23611 or the study plan is documented
and distributed?
Answers to these questions are given in Clause 5 to Clause 8.
5 Objectives of sampling
5.1 General
Biological soil investigations address a number of different questions related to the status of invertebrates
living in or on the soil (including many different species belonging to different trophic, taxonomic, physiological
or functional groups and size classes), often after or under some kind of anthropogenic impact. In the case of
ecotoxicological questions, usually laboratory tests are used to study the effects of the impact (e.g. chemicals
added to the soil) on invertebrates and thus on the soil quality in general. Such methods are presented in
ISO 15799, while the assessment of the test results is given in ISO 17616. Further guidance on sampling, collection,
handling and preparation of contaminated soil for biological (i.e. ecotoxicological) testing has currently been
prepared by Reference [13]. This is particularly important for the identification and characterization of field
reference soils which are necessary for the determination of biological reference values.
5.2 General remarks
As stated in the Introduction, the principal objectives of sampling soil invertebrates can be distinguished as
follows:
— the performance of the site-specific characterization and assessment of contaminated land;
— the study of potential side effects of anthropogenic impacts (e.g. the application of chemicals or the
building of roads);
— the biological classification and assessment of soils in order to determine the biological condition of soils;
— long-term biogeographical monitoring in the context of nature protection or restoration, including global
change (e.g. as in long-term ecological research projects (LTERs)).
To a different degree, all four objectives include the determination of biological reference (or base-line)
values, meaning that it shall be clarified which community of soil organisms occurs in a specific soil
assuming that there is no anthropogenic impact. Since this precondition is, in many if not all soils, not
fulfilled any more, such a “normal” state shall be defined, e.g. by sampling of reference soils. These soils have
been selected based on criteria like being representative for certain regions or land-use forms or lack of
contamination, Reference [18].
The use of the soil and site are of varying importance depending on the primary objective of an investigation.
The results obtained from sampling can indicate a need for further investigation, e.g. detected contamination
can indicate a need for identification and assessment of potential hazards and risks. However, assessment
of such hazards or risks is not covered by this part of ISO 23611. In addition, capture-recapture methods

ISO/DIS 23611-6:2025(en)
– while often used in ecology for terrestrial above-ground invertebrates (e.g. spiders, Reference [19]) are
rarely used in general monitoring schemes and thus will not be covered in this part of ISO 23611.
Often soil invertebrates are a part of an entire monitoring effort that includes other biological (mainly
microbial), as well as pedological, climatic and possibly also agricultural parameters. If such monitoring
programmes are performed at regular intervals, permanent sampling sites shall be set up. In such a case,
additional efforts are mandatory in order to secure an effective exchange of information. Sampling is usually
carried out within the main rooting zone (rarely at greater depths since most soil invertebrates live within
the uppermost 30 cm of the soil). Soil horizons or layers may or may not be separately sampled (samples
shall be labelled accordingly).
To adequately support legal or regulatory action, particular attention should be paid to all aspects of quality
assurance. The guidance given in ISO 10381-5 is particularly relevant. After clarifying the most important
pre-conditions, the four groups of main objectives as given above are briefly presented in the following
subclauses. However, it should be kept in mind that, in reality, one specific study can fit into more than one
of these groups.
5.3 Pre-conditions
Before designing a field study with soil invertebrates, it is highly recommended to characterize the
respective area pedologically, Reference [20]. Depending on the principal objectives, it is usually necessary
to determine for the body of soil or part thereof
— the nature, concentrations and distribution of naturally occurring substances,
— the nature, concentrations and distribution of contaminants,
— the physical and chemical properties and variations,
— the anthropogenic impact at that site, in particular the land use history (including vegetation cover).
It is often necessary to take into account changes in the above-mentioned variables with time and space
(vertically, horizontally), caused by either natural (e.g. climatic) or anthropogenic activities.
In addition, pH, particle size distribution, C/N ratio, organic matter and organic carbon content, total
nitrogen, cation exchange capacity and water holding capacity of the soil should be measured in accordance
with ISO 10390, ISO 10694, ISO 11260, ISO 11272, ISO 11274, ISO 11277, ISO 13878, ISO 11461, ISO 11465,
ISO 15709, ISO 17616.
5.4 The performance of the site-specific assessment of contaminated land
When land is contaminated with chemicals and other substances that are potentially acting as pollutants
to the environment, it can be necessary to carry out an investigation as a part of a hazard and/or risk
assessment. This includes to determine the nature and extent of contamination, to identify hazards
associated with the contamination, to identify potential targets and routes of exposure, and to evaluate the
environmental risks related to the current and future use of the site and neighbouring land. A sampling
programme for risk assessment can also comply with legal or regulatory requirements and careful attention
to sample integrity is recommended. An extensive overview of the benefits and limitations of biological
parameters as a component of contaminated land assessment is given in Reference [13].
5.5 The study of potential side effects of anthropogenic impacts
Sampling can be required following an anthropogenic effect such as the input of undesirable material
(mainly chemicals) which can be from a point source or from a diffuse source. Another example can be the
building of roads. The study design needs again to be developed on a site-specific basis. Sampling can also be
required to establish base-line conditions prior to an activity, which might affect the composition or quality
of soil.
NOTE Such base-line sampling can also be performed as part of a biological soil classification and assessment
(see 5.4).
ISO/DIS 23611-6:2025(en)
5.6 The biological classification and assessment of soils in order to determine the
biological quality of soils
This is typically carried out at (irregular) time intervals to determine the biological quality of a soil for a
particular purpose (e.g. as part of a large-scale screening programme or in the context of a local planning
activity). The information gained here can be used for the preparation of biological soil maps, Reference [21].
NOTE The study of the biological soil quality can also be used for the determination of “base-line conditions” in
the context of the assessment of anthropogenic impacts (see 5.3) or of long-term changes such as global warming (5.7).
5.7 Biogeographical monitoring in nature protection or restoration
Finally, the information gained in sampling programmes extends the knowledge on the biogeography of soil
organisms, which is necessary in the context of nature protection and conservation, in particular concerning
long-term changes like global warming. So far, only few soil invertebrates (mainly beetles or other insects
which in their larval stage live in the soil) have been put on the Red List of endangered species (https://
www .iucnredlist .org/ statistics). Also there is little proof that such species have been eradicated in modern
times. However, in both cases, this fact is mainly caused by the poor level of knowledge on these species;
many species can have died out without notice. Sampling programmes can also determine whether soil-
biological assemblages (site-specifically) expected in a region become established during nature restoration
or after remediation measures (control of success).
6 Samples and sampling points
6.1 General
The selection, location and preparation of the sampling points depend on the objectiv
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