SIST ISO 18512:2018
Soil quality - Guidance on long and short term storage of soil samples
Soil quality - Guidance on long and short term storage of soil samples
This International Standard gives guidance on how to store and preserve soil samples for laboratory
determinations and how to prepare them for analysis after storage. Special emphasis is given to maximum
storage times as a function of different storage conditions.
Qualité du sol - Lignes directrices relatives au stockage des échantillons de sol à long et à court termes
L'ISO 18512:2007 donne des lignes directrices relatives au stockage et � la conservation des �chantillons de sol destin�s aux d�terminations de laboratoire, ainsi qu'� leur pr�paration en vue d'une analyse apr�s stockage. Une attention toute particuli�re est port�e aux dur�es maximales de stockage en fonction des diff�rentes conditions de conservation.
Kakovost tal - Navodilo za dolgoročno in kratkoročno shranjevanje vzorcev tal
Ta mednarodni standard podaja smernice za načine shranjevanja in ohranjanja vzorcev prsti za laboratorijsko določevanje ter načine njihove priprave za analizo po skladiščenju vzorcev. Poseben poudarek je na najdaljših obdobjih skladiščenja glede na različne pogoje skladiščenja.
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INTERNATIONAL ISO
STANDARD 18512
First edition
2007-08-15
Soil quality — Guidance on long
and short term storage of soil samples
Qualité du sol — Lignes directrices relatives au stockage
des échantillons de sol à long et à court termes
Reference number
ISO 18512:2007(E)
©
ISO 2007
---------------------- Page: 1 ----------------------
ISO 18512:2007(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
COPYRIGHT PROTECTED DOCUMENT
© ISO 2007
All rights reserved. Unless otherwise specified, no Part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2007 – All rights reserved
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ISO 18512:2007(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 3
4 General comments on soil storage. 3
5 Change in soil properties during storage . 4
6 Storage conditions . 4
6.1 General. 4
6.2 Light. 4
6.3 Temperature. 4
6.4 Humidity. 4
6.5 Accessibility, security, documentation and quality control. 5
6.6 Duration of storage. 5
6.7 Containers and quantity of sample stored. 5
6.8 Preparing the samples after storage . 5
7 Stepwise scheme. 6
8 Step A: Consideration of need for further analysis and duration of storage. 6
9 Step B: Consideration of parameters currently relevant to the study . 6
10 Step C: Consideration of parameters which may be of interest in the future. 6
11 Step D: Consideration of how each of these parameters may be affected by storage
conditions. 7
11.1 General. 7
11.2 Soil characteristics. 7
11.3 Chemical parameters. 7
11.4 Biological tests. 10
12 Step E: Design of storage conditions required to avoid change in sample properties . 11
13 Step F: Design of documentation and labelling scheme including sample management. 11
14 Step G: Estimation of costs for storage and documentation and comparison of these
costs with available or expected funding. 11
15 Test report. 12
Annex A (normative) Storage for soil samples . 13
Bibliography . 16
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ISO 18512:2007(E)
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 18512 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 2, Sampling.
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ISO 18512:2007(E)
Introduction
Many soil investigation programmes require that soil samples be stored for future use. The choice of storage
conditions may determine whether or not the samples will be suitable for the intended future use. This
International Standard gives guidance on choosing conditions for storage of soil samples.
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INTERNATIONAL STANDARD ISO 18512:2007(E)
Soil quality — Guidance on long and short term storage of soil
samples
1 Scope
This International Standard gives guidance on how to store and preserve soil samples for laboratory
determinations and how to prepare them for analysis after storage. Special emphasis is given to maximum
storage times as a function of different storage conditions.
2 Normative references
The following referenced documents are indispensable for the application 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.
EN 15192:2006, Characterisation of waste and soil — Determination of Chromium(VI) in solid material by
alkaline digestion and ion chromatography with spectrophotometric detection
ISO 10301, Water quality — Determination of highly volatile halogenated hydrocarbons —
Gas-chromatographic methods
ISO 10381-6, Soil quality — Sampling — Part 6: Guidance on the collection, handling and storage of soil
under aerobic conditions for the assessment of microbiological processes, biomass and diversity in the
laboratory
ISO 10382, Soil quality — Determination of organochlorine pesticides and polychlorinated biphenyls —
Gas-chromatographic method with electron capture detection
ISO 10390, Soil quality — Determination of pH
ISO 10694, Soil quality — Determination of organic and total carbon after dry combustion (elementary
analysis)
ISO 11048, Soil quality — Determination of water-soluble and acid-soluble sulfate
ISO 11074, Soil quality — Vocabulary
ISO 11259, Soil quality — Simplified soil description
ISO 11261, Soil quality — Determination of total nitrogen — Modified Kjeldahl method
ISO 11263, Soil quality — Determination of phosphorus — Spectrometric determination of phosphorus soluble
in sodium hydrogen carbonate solution
ISO 11265, Soil quality — Determination of the specific electrical conductivity
ISO 11266, Soil quality — Guidance on laboratory testing for biodegradation of organic chemicals in soil under
aerobic conditions
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ISO 18512:2007(E)
ISO 11267, Soil quality — Inhibition of reproduction of Collembola (Folsomia candida) by soil pollutants
ISO 11268-1, Soil quality — Effects of pollutants on earthworms (Eisenia fetida) — Part 1: Determination of
acute toxicity using artificial soil substrate
ISO 11268-2, Soil quality — Effects of pollutants on earthworms (Eisenia fetida) — Part 2: Determination of
effects on reproduction
ISO 11466, Soil quality — Extraction of trace elements soluble in aqua regia
ISO 13877, Soil quality — Determination of polynuclear aromatic hydrocarbons — Method using
high-performance liquid chromatography
ISO 13878, Soil quality — Determination of total nitrogen content by dry combustion (“elemental analysis”)
ISO 14154, Soil quality — Determination of some selected chlorophenols — Gas-chromatographic method
with electron-capture detection
ISO 14238, Soil quality — Biological methods — Determination of nitrogen mineralization and nitrification in
soils and the influence of chemicals on these processes
ISO 14240-1, Soil quality — Determination of soil microbial biomass — Part 1: Substrate-induced respiration
method
ISO 14240-2, Soil quality — Determination of soil microbial biomass — Part 2: Fumigation-extraction method
ISO 14255, Soil quality — Determination of nitrate nitrogen, ammonium nitrogen and total soluble nitrogen in
air-dry soils using calcium chloride solution as extractant
ISO/TS 14256-1, Soil quality — Determination of nitrate, nitrite and ammonium in field-moist soils by extraction
with potassium chloride solution — Part 1: Manual method
ISO 14507, Soil quality — Pretreatment of samples for determination of organic contaminants
ISO 15009, Soil quality — Gas chromatographic determination of the content of volatile aromatic
hydrocarbons, naphthalene and volatile halogenated hydrocarbons — Purge-and-trap method with thermal
desorption
ISO 15473, Soil quality — Guidance on laboratory testing for biodegradation of organic chemicals in soil under
anaerobic conditions
ISO 15685, Soil quality — Determination of potential nitrification and inhibition of nitrification — Rapid test by
ammonium oxidation
ISO 15799, Soil quality — Guidance on the ecotoxicological characterization of soils and soil materials
ISO 15903, Soil quality — Format for recording soil and site information
ISO 15952, Soil quality — Effects of pollutants on juvenile land snails (Helicidae) — Determination of the
effects on growth by soil contamination
ISO 16072, Soil quality — Laboratory methods for determination of microbial soil respiration
ISO 16387, Soil quality — Effects of pollutants on Enchytraeidae (Enchytraeus sp.) — Determination of effects
on reproduction and survival
ISO 16703, Soil quality — Determination of content of hydrocarbon in the range C10 to C40 by gas
chromatography
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ISO 18512:2007(E)
ISO 17155, Soil quality — Determination of abundance and activity of soil microflora using respiration curves
ISO 20963, Soil quality — Effects of pollutants on insect larvae (Oxythyrea funesta) — Determination of acute
toxicity
ISO 22030, Soil quality — Biological methods — Chronic toxicity in higher plants
ISO 22155, Soil quality — Gas chromatographic quantitative determination of volatile aromatic and
halogenated hydrocarbons and selected ethers — Static headspace method
ISO 23753-1, Soil quality — Determination of dehydrogenase activity in soils — Part 1: Method using
triphenyltetrazolium chloride (TTC)
ISO 23753-2, Soil quality — Determination of dehydrogenase activity in soils — Part 2: Method using
iodotetrazolium chloride (INT)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11074 and ISO 11259 apply.
In this International Standard, the term “refrigeration” refers to a temperature of 4 °C ± 2 °C. The term
“freezing” refers to a temperature lower than –18 °C.
4 General comments on soil storage
Many studies involve the collection of soil samples in the field, followed by laboratory determination of various
properties of the collected samples. In general, the samples are taken at the site being investigated, mixed or
otherwise treated at the site, packed in containers and then transported to the laboratory. Upon arrival at the
laboratory, the samples may again be treated before being sent for analysis. Some samples may be stored
directly for later analysis. After analysis, the remaining part of the samples may be discarded or stored. The
samples are stored when there is a need for further analysis, either because there is a need for checking
parameters already determined or there is a need for making additional determinations in the future.
In practice, there are two main situations in which sample storage is relevant.
⎯ Routine testing of soil samples, e.g. by environmental laboratories, where soil samples typically are
stored for a few weeks after sampling in order to carry out some additional tests, or in order to confirm
results found earlier.
⎯ Situations in which samples have to be stored for a long period, sometimes over decades, e.g. monitoring
programs, reference materials, or research programs in which degradability is tested.
Both these situations fall within the scope of this International Standard.
The conditions for storage should be selected carefully at all stages, from the point of taking the sample
onwards. As an unexpected delay in transport may occur, this guidance should be applied even if the planned
transportation time is short. Examples of storage conditions to be considered are light, temperature, humidity,
accessibility, duration of storage, type of container and amount of sample to be stored. Documentation of the
samples and the storage conditions is also important. Risk and security problems should be considered. Well-
designed storage conditions are particularly important in large-scale studies, such as monitoring, where the
number of samples may become quite large over the years. Incorrectly chosen storage conditions may lead to
high costs and may render the samples unfit for future use.
The effect of storage on biodiversity has been considered only with respect to microbiological diversity.
Radioactive change caused by loss or gain of radioactive matter should be considered in connection with the
respective compounds. Radioactive decay is generally not affected by storage and is not treated in this
International Standard.
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ISO 18512:2007(E)
5 Change in soil properties during storage
It is helpful to consider the principal biological, chemical and physical phenomena that may cause changes in
the samples:
⎯ change in water content;
⎯ biological activity;
⎯ evaporation or precipitation of volatile substances;
⎯ chemical reactions with the atmosphere;
⎯ reactions with the sample container.
Unacceptable changes in soil parameters may occur if these phenomena are not controlled by a proper
choice of storage conditions. However, controlling all these phenomena in all samples for a long period of time
may turn out to be very costly or impossible. It is therefore important to design the storage conditions to fit the
objectives of the study.
It is worth noting that some parameters, for example, the contents of some volatile substances, may not be
measurable after storage, regardless of storage conditions. In such cases, serious consideration for the future
need for data on such parameters should be given at the outset, and the analysis program adapted
accordingly.
6 Storage conditions
6.1 General
This clause contains a list of storage conditions that shall be determined when designing the storage
programme.
6.2 Light
Light conditions affect the content of some substances, particularly organics. This should be considered and
taken care of, e.g. by using brown glass bottles or keeping the samples in total darkness.
6.3 Temperature
The choice of temperature is always very important as the temperature affects the biological activity in the
samples. Temperature is therefore a major factor in the design of a storage facility. In some cases, room
temperature will be appropriate but, in many cases, refrigeration or freezing may be required to reduce the
biological activity. In very special cases, the temperature of liquid nitrogen will be required.
The need for storage of a few samples at – 80 °C or a lower temperature should be considered, e.g. storage
of higher quality reference samples at – 80 °C or at a lower temperature, in order to demonstrate whether or
not samples stored at low temperatures are stable.
6.4 Humidity
Moisture will induce microbiological activity or chemical changes in soil samples unless the temperature is
very low. The control of humidity is therefore important.
When the samples are not kept in airtight containers, the humidity of the storage facility shall be kept low all
year round.
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ISO 18512:2007(E)
If airtight containers are used, the sample humidity will not change during storage. In this case, it is necessary
to ascertain that the original humidity of the samples is low enough to prevent microbiological activity.
6.5 Accessibility, security, documentation and quality control
If the samples are to be analysed urgently, or repeatedly, the storage facility should be easily accessible from
the laboratory. This will reduce the time and the risk for quality deterioration during transport to the laboratory.
Security issues, such as fire, theft and destruction, are also important, particularly for samples of great value.
Documentation (see ISO 15903), proper labelling and elimination of cross-contamination are other safety
issues to be addressed.
Samples from contaminated land should always be regarded as hazardous and handled accordingly.
A relevant quality control (QC) programme should be introduced. A (certified) reference sample may be used,
or a prior analysis on one or more of the freshly taken samples.
6.6 Duration of storage
The required duration of storage is an important element in the storage conditions. As mentioned in Clause 4,
some samples are stored only for a few weeks (e.g. for routine environmental testing), other samples for a
long period of time. Well-documented long-term “reference” soil samples collected at regular intervals, over
many years, could be used to determine the magnitude of any changes in important soil properties. There
may also be legal requirements on the duration of storage.
The need for a long duration of storage should always be evaluated versus the cost of storage and
documentation.
6.7 Containers and quantity of sample stored
The containers should be carefully chosen regarding the construction material, type of sealing and size.
Relevant functions should be validated, e.g. the protection from contamination and the ability to keep the
sample protected from light or air. Appropriate cleaning or sterilizing procedures shall be followed.
Many plastic containers will become brittle after five to ten years and glass containers are preferred. However,
if the samples contain a high content of water, as many clay samples do, the glass may crack on freezing. The
risk of cracking on freezing can be reduced by partial filling of the bottles.
The amount of sample to be stored should be considered. The amount required depends on the planned
determinations and may be difficult to calculate. Unless the material is very costly or the need for reanalysis is
very unlikely, it is wise to store enough material for at least five determinations of the parameter requiring the
largest sample size. In addition, storage of at least 50 g is recommended in order to allow homogeneity.
Once a soil is frozen, it is very difficult to sub-sample for a repeat analysis. Thus, it is wise to freeze a number
of smaller sub-samples. Care should be taken to guarantee the homogeneity when sub-samples are prepared.
6.8 Preparing the samples after storage
Appropriate procedures for preparing the samples after storage will depend on the storage conditions and the
determinations. It is not possible to give a general specification. Existing standards (e. g. ISO 11464) should
be considered.
When a non-frozen soil sample is stored for a long period of time, a vertical redistribution of particles may
occur. Remixing in a suitable mixer is advisable. For large samples, remixing in a mixer may not be sufficient.
Mixing by spreading the sample in a thin layer on a plastic foil, then repeatedly folding the layer and spreading
it out again, is recommended.
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ISO 18512:2007(E)
For frozen samples, thawing conditions shall be defined, as they can influence the determination of biological,
microbiological and organic parameters. The samples shall be thawed in their original bags or containers.
7 Stepwise scheme
This International Standard is based on a simple stepwise procedure that enables an informed decision on the
choice of conditions for storage and preservation which can be considered in advance of the collection of
samples in the field.
The steps are given below.
Step A Consideration of the need for further analysis and duration of storage (Clause 8).
Step B Consideration of parameters presently relevant to the study (Clause 9).
Step C Consideration of parameters that may be of interest in the future (Clause 10).
Step D Consideration of how each of these parameters may be affected by storage conditions (Clause 11).
Step E Design of storage conditions to prevent changes in sample properties (Clause 12).
Step F Design of documentation and labelling scheme including sample management (Clause 13).
Step G Estimation of costs for storage and documentation and comparison of these costs with available or
expected funding (Clause 14).
8 Step A: Consideration of need for further analysis and duration of storage
If there is no need for further analysis, there is little cause for sample storage. There are many reasons for
further analysis which should be considered. Examples:
⎯ resources may not be available at the time of sampling for all the determinations required;
⎯ methods for all the determinations required may not be available at the time of sampling;
⎯ there may be uncertainty in the method chosen which calls for possible further analysis;
⎯ legal requirements for possibility of further analysis may exist;
⎯ expansion of the analytical programme depending on the results of preliminary analyses should be
considered.
9 Step B: Consideration of parameters currently relevant to the study
The soil properties of interest should be part of the study programme for which the samples have been
collected. In order to make an informed decision on the storage conditions, it is important to go through this list
of relevant parameters.
Existing ISO soil standard parameters should usually be given high priority.
10 Step C: Consideration of parameters which may be of interest in the future
The possibility of new parameters being included in the study at a later date should always be considered.
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ISO 18512:2007(E)
11 Step D: Consideration of how each of these parameters may be affected by
storage conditions
11.1 General
The consideration of how each of the parameters defined in Steps B and C may be affected by storage
conditions is a critical step. If the number of parameters is large, step D may be time consuming. In monitoring
programmes, there may be 50 or more parameters.
Grouping of the parameters, as shown in 11.3-11.4, is strongly recommended.
This International Standard does not aim to give specific information on the effect of all storage conditions on
all possible parameters. The information presented below is a selection based on common requirements.
Due to the small number of studies, there is sometimes a lack of scientific evidence on how long-time storage
affects the parameters to be measured. General experience has been accumulated in Table A.1 in Annex A.
11.2 Soil characteristics
11.2.1 Electrical conductivity
The electrical conductivity reflects the salt content of the soil and should not vary much with time.
11.2.2 pH
In air-dried or frozen soil samples, the pH is not expected to change during storage for several years. Studies
have shown that no difference in pH could be observed in samples stored for up to 6 months at temperatures
[7]
between – 18 °C and – 150 °C, liquid nitrogen
11.2.3 Water-holding capacity
Freezing may change the water-holding capacity of soil. If the water-holding capacity of the sample after
storage is of interest, the value has to be remeasured.
11.2.4 Structural stability
Samples taken for assessment of the structural stability of soil cannot be frozen, as freezing disrupts the
structure of the soil. If the stability in the field state is required, samples cannot even be dried. On this basis,
they should be treated without delay.
11.3 Chemical parameters
11.3.1 Metals and trace elements
Provided that the air-dried soil samples have been stored at room temperature in glass containers or in sealed
polyethylene bags further protected by dust-tight plastic containers, the storage time is generally at least
7 years for subsequent extraction by quite strong and strong extracting solutions for the determination of the
macronutrients K, Mg, Ca and the trace elements As, Be, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, V, Zn. Examples of
quite strong and strong extracting solutions are Mehlich 2 and Mehlich 3 extractants, 2 mol/l HNO and aqua
3
regia. Cr(VI) is stable for 30 days after sample collection in wet soil at refrigeration. The risk of loss of mercury
in elemental form or in volatile compounds shall be considered.
When using a weak extracting solution (e.g. 0,01 mol/l CaCl ) the soil samples shall be refrigerated to ensure
2
long-term stability. Some measured extractable nutrient concentrations were found to be changed by storage
[3]
at elevated temperatures .
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ISO 18512:2007(E)
11.3.2 Total nitrogen and nitrogen compounds
Nitrogen in soil appears in inorganic forms, mainly nitrate and ammonium ions, and in organic forms as
organic compounds, some of which are a part of the microbial soil biomass. The dynamic balance between
these forms cause a major problem when storing soil samples for determination of nitrogen and its
compounds. The most significant factor affecting this balance is the soil biological activity that is dependent on
the aeration, temperature and humidity of the soil. All these parameter
...
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Qualité du sol - Lignes directrices relatives au stockage des échantillons de sol à long et à court termesSoil quality - Guidance on long and short term storage of soil samples13.080.05Preiskava tal na splošnoExamination of soils in generalICS:Ta slovenski standard je istoveten z:ISO 18512:2007SIST ISO 18512:2018en,fr,de01-julij-2018SIST ISO 18512:2018SLOVENSKI
STANDARD
SIST ISO 18512:2018
Reference numberISO 18512:2007(E)© ISO 2007
INTERNATIONAL STANDARD ISO18512First edition2007-08-15Soil quality — Guidance on long and short term storage of soil samples Qualité du sol — Lignes directrices relatives au stockage des échantillons de sol à long et à court termes
SIST ISO 18512:2018
ISO 18512:2007(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
COPYRIGHT PROTECTED DOCUMENT
©
ISO 2007 All rights reserved. Unless otherwise specified, no Part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56 • CH-1211 Geneva 20 Tel.
+ 41 22 749 01 11 Fax
+ 41 22 749 09 47 E-mail
copyright@iso.org Web
www.iso.org Published in Switzerland
ii © ISO 2007 – All rights reserved
SIST ISO 18512:2018
ISO 18512:2007(E) © ISO 2007 – All rights reserved iiiContents Page Foreword.iv Introduction.v 1 Scope.1 2 Normative references.1 3 Terms and definitions.3 4 General comments on soil storage.3 5 Change in soil properties during storage.4 6 Storage conditions.4 6.1 General.4 6.2 Light.4 6.3 Temperature.4 6.4 Humidity.4 6.5 Accessibility, security, documentation and quality control.5 6.6 Duration of storage.5 6.7 Containers and quantity of sample stored.5 6.8 Preparing the samples after storage.5 7 Stepwise scheme.6 8 Step A: Consideration of need for further analysis and duration of storage.6 9 Step B: Consideration of parameters currently relevant to the study.6 10 Step C: Consideration of parameters which may be of interest in the future.6 11 Step D: Consideration of how each of these parameters may be affected by storage conditions.7 11.1 General.7 11.2 Soil characteristics.7 11.3 Chemical parameters.7 11.4 Biological tests.10 12 Step E: Design of storage conditions required to avoid change in sample properties.11 13 Step F: Design of documentation and labelling scheme including sample management.11 14 Step G: Estimation of costs for storage and documentation and comparison of these costs with available or expected funding.11 15 Test report.12 Annex A (normative)
Storage for soil samples.13 Bibliography.16
SIST ISO 18512:2018
ISO 18512:2007(E) iv © ISO 2007 – All rights reserved 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. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 18512 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 2, Sampling. SIST ISO 18512:2018
ISO 18512:2007(E) © ISO 2007 – All rights reserved vIntroduction Many soil investigation programmes require that soil samples be stored for future use. The choice of storage conditions may determine whether or not the samples will be suitable for the intended future use. This International Standard gives guidance on choosing conditions for storage of soil samples.
SIST ISO 18512:2018
SIST ISO 18512:2018
INTERNATIONAL STANDARD ISO 18512:2007(E) © ISO 2007 – All rights reserved 1Soil quality — Guidance on long and short term storage of soil samples 1 Scope This International Standard gives guidance on how to store and preserve soil samples for laboratory determinations and how to prepare them for analysis after storage. Special emphasis is given to maximum storage times as a function of different storage conditions. 2 Normative references The following referenced documents are indispensable for the application 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. EN 15192:2006, Characterisation of waste and soil — Determination of Chromium(VI) in solid material by alkaline digestion and ion chromatography with spectrophotometric detection ISO 10301, Water quality — Determination of highly volatile halogenated hydrocarbons — Gas-chromatographic methods ISO 10381-6, Soil quality — Sampling — Part 6: Guidance on the collection, handling and storage of soil under aerobic conditions for the assessment of microbiological processes, biomass and diversity in the laboratory ISO 10382, Soil quality — Determination of organochlorine pesticides and polychlorinated biphenyls — Gas-chromatographic method with electron capture detection ISO 10390, Soil quality — Determination of pH ISO 10694, Soil quality — Determination of organic and total carbon after dry combustion (elementary analysis) ISO 11048, Soil quality — Determination of water-soluble and acid-soluble sulfate ISO 11074, Soil quality — Vocabulary ISO 11259, Soil quality — Simplified soil description ISO 11261, Soil quality — Determination of total nitrogen — Modified Kjeldahl method ISO 11263, Soil quality — Determination of phosphorus — Spectrometric determination of phosphorus soluble in sodium hydrogen carbonate solution ISO 11265, Soil quality — Determination of the specific electrical conductivity ISO 11266, Soil quality — Guidance on laboratory testing for biodegradation of organic chemicals in soil under aerobic conditions SIST ISO 18512:2018
ISO 18512:2007(E) 2 © ISO 2007 – All rights reserved ISO 11267, Soil quality — Inhibition of reproduction of Collembola (Folsomia candida) by soil pollutants ISO 11268-1, Soil quality — Effects of pollutants on earthworms (Eisenia fetida) — Part 1: Determination of acute toxicity using artificial soil substrate ISO 11268-2, Soil quality — Effects of pollutants on earthworms (Eisenia fetida) — Part 2: Determination of effects on reproduction ISO 11466, Soil quality — Extraction of trace elements soluble in aqua regia ISO 13877, Soil quality — Determination of polynuclear aromatic hydrocarbons — Method using high-performance liquid chromatography ISO 13878, Soil quality — Determination of total nitrogen content by dry combustion (“elemental analysis”) ISO 14154, Soil quality — Determination of some selected chlorophenols — Gas-chromatographic method with electron-capture detection ISO 14238, Soil quality — Biological methods — Determination of nitrogen mineralization and nitrification in soils and the influence of chemicals on these processes ISO 14240-1, Soil quality — Determination of soil microbial biomass — Part 1: Substrate-induced respiration method ISO 14240-2, Soil quality — Determination of soil microbial biomass — Part 2: Fumigation-extraction method ISO 14255, Soil quality — Determination of nitrate nitrogen, ammonium nitrogen and total soluble nitrogen in air-dry soils using calcium chloride solution as extractant ISO/TS 14256-1, Soil quality — Determination of nitrate, nitrite and ammonium in field-moist soils by extraction with potassium chloride solution — Part 1: Manual method ISO 14507, Soil quality — Pretreatment of samples for determination of organic contaminants ISO 15009, Soil quality — Gas chromatographic determination of the content of volatile aromatic hydrocarbons, naphthalene and volatile halogenated hydrocarbons — Purge-and-trap method with thermal desorption ISO 15473, Soil quality — Guidance on laboratory testing for biodegradation of organic chemicals in soil under anaerobic conditions ISO 15685, Soil quality — Determination of potential nitrification and inhibition of nitrification — Rapid test by ammonium oxidation ISO 15799, Soil quality — Guidance on the ecotoxicological characterization of soils and soil materials ISO 15903, Soil quality — Format for recording soil and site information ISO 15952, Soil quality — Effects of pollutants on juvenile land snails (Helicidae) — Determination of the effects on growth by soil contamination ISO 16072, Soil quality — Laboratory methods for determination of microbial soil respiration ISO 16387, Soil quality — Effects of pollutants on Enchytraeidae (Enchytraeus sp.) — Determination of effects on reproduction and survival ISO 16703, Soil quality — Determination of content of hydrocarbon in the range C10 to C40 by gas chromatography SIST ISO 18512:2018
ISO 18512:2007(E) © ISO 2007 – All rights reserved 3ISO 17155, Soil quality — Determination of abundance and activity of soil microflora using respiration curves ISO 20963, Soil quality — Effects of pollutants on insect larvae (Oxythyrea funesta) — Determination of acute toxicity ISO 22030, Soil quality — Biological methods — Chronic toxicity in higher plants ISO 22155, Soil quality — Gas chromatographic quantitative determination of volatile aromatic and halogenated hydrocarbons and selected ethers — Static headspace method ISO 23753-1, Soil quality — Determination of dehydrogenase activity in soils — Part 1: Method using triphenyltetrazolium chloride (TTC) ISO 23753-2, Soil quality — Determination of dehydrogenase activity in soils — Part 2: Method using iodotetrazolium chloride (INT) 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 11074 and ISO 11259 apply. In this International Standard, the term “refrigeration” refers to a temperature of 4 °C ± 2 °C. The term “freezing” refers to a temperature lower than –18 °C. 4 General comments on soil storage Many studies involve the collection of soil samples in the field, followed by laboratory determination of various properties of the collected samples. In general, the samples are taken at the site being investigated, mixed or otherwise treated at the site, packed in containers and then transported to the laboratory. Upon arrival at the laboratory, the samples may again be treated before being sent for analysis. Some samples may be stored directly for later analysis. After analysis, the remaining part of the samples may be discarded or stored. The samples are stored when there is a need for further analysis, either because there is a need for checking parameters already determined or there is a need for making additional determinations in the future. In practice, there are two main situations in which sample storage is relevant. ⎯ Routine testing of soil samples, e.g. by environmental laboratories, where soil samples typically are stored for a few weeks after sampling in order to carry out some additional tests, or in order to confirm results found earlier. ⎯ Situations in which samples have to be stored for a long period, sometimes over decades, e.g. monitoring programs, reference materials, or research programs in which degradability is tested. Both these situations fall within the scope of this International Standard. The conditions for storage should be selected carefully at all stages, from the point of taking the sample onwards. As an unexpected delay in transport may occur, this guidance should be applied even if the planned transportation time is short. Examples of storage conditions to be considered are light, temperature, humidity, accessibility, duration of storage, type of container and amount of sample to be stored. Documentation of the samples and the storage conditions is also important. Risk and security problems should be considered. Well-designed storage conditions are particularly important in large-scale studies, such as monitoring, where the number of samples may become quite large over the years. Incorrectly chosen storage conditions may lead to high costs and may render the samples unfit for future use. The effect of storage on biodiversity has been considered only with respect to microbiological diversity. Radioactive change caused by loss or gain of radioactive matter should be considered in connection with the respective compounds. Radioactive decay is generally not affected by storage and is not treated in this International Standard. SIST ISO 18512:2018
ISO 18512:2007(E) 4 © ISO 2007 – All rights reserved 5 Change in soil properties during storage It is helpful to consider the principal biological, chemical and physical phenomena that may cause changes in the samples: ⎯ change in water content; ⎯ biological activity; ⎯ evaporation or precipitation of volatile substances; ⎯ chemical reactions with the atmosphere; ⎯ reactions with the sample container. Unacceptable changes in soil parameters may occur if these phenomena are not controlled by a proper choice of storage conditions. However, controlling all these phenomena in all samples for a long period of time may turn out to be very costly or impossible. It is therefore important to design the storage conditions to fit the objectives of the study. It is worth noting that some parameters, for example, the contents of some volatile substances, may not be measurable after storage, regardless of storage conditions. In such cases, serious consideration for the future need for data on such parameters should be given at the outset, and the analysis program adapted accordingly. 6 Storage conditions 6.1 General This clause contains a list of storage conditions that shall be determined when designing the storage programme. 6.2 Light Light conditions affect the content of some substances, particularly organics. This should be considered and taken care of, e.g. by using brown glass bottles or keeping the samples in total darkness. 6.3 Temperature The choice of temperature is always very important as the temperature affects the biological activity in the samples. Temperature is therefore a major factor in the design of a storage facility. In some cases, room temperature will be appropriate but, in many cases, refrigeration or freezing may be required to reduce the biological activity. In very special cases, the temperature of liquid nitrogen will be required. The need for storage of a few samples at – 80 °C or a lower temperature should be considered, e.g. storage of higher quality reference samples at – 80 °C or at a lower temperature, in order to demonstrate whether or not samples stored at low temperatures are stable. 6.4 Humidity Moisture will induce microbiological activity or chemical changes in soil samples unless the temperature is very low. The control of humidity is therefore important. When the samples are not kept in airtight containers, the humidity of the storage facility shall be kept low all year round. SIST ISO 18512:2018
ISO 18512:2007(E) © ISO 2007 – All rights reserved 5If airtight containers are used, the sample humidity will not change during storage. In this case, it is necessary to ascertain that the original humidity of the samples is low enough to prevent microbiological activity. 6.5 Accessibility, security, documentation and quality control If the samples are to be analysed urgently, or repeatedly, the storage facility should be easily accessible from the laboratory. This will reduce the time and the risk for quality deterioration during transport to the laboratory. Security issues, such as fire, theft and destruction, are also important, particularly for samples of great value. Documentation (see ISO 15903), proper labelling and elimination of cross-contamination are other safety issues to be addressed. Samples from contaminated land should always be regarded as hazardous and handled accordingly. A relevant quality control (QC) programme should be introduced. A (certified) reference sample may be used, or a prior analysis on one or more of the freshly taken samples. 6.6 Duration of storage The required duration of storage is an important element in the storage conditions. As mentioned in Clause 4, some samples are stored only for a few weeks (e.g. for routine environmental testing), other samples for a long period of time. Well-documented long-term “reference” soil samples collected at regular intervals, over many years, could be used to determine the magnitude of any changes in important soil properties. There may also be legal requirements on the duration of storage. The need for a long duration of storage should always be evaluated versus the cost of storage and documentation. 6.7 Containers and quantity of sample stored The containers should be carefully chosen regarding the construction material, type of sealing and size. Relevant functions should be validated, e.g. the protection from contamination and the ability to keep the sample protected from light or air. Appropriate cleaning or sterilizing procedures shall be followed. Many plastic containers will become brittle after five to ten years and glass containers are preferred. However, if the samples contain a high content of water, as many clay samples do, the glass may crack on freezing. The risk of cracking on freezing can be reduced by partial filling of the bottles. The amount of sample to be stored should be considered. The amount required depends on the planned determinations and may be difficult to calculate. Unless the material is very costly or the need for reanalysis is very unlikely, it is wise to store enough material for at least five determinations of the parameter requiring the largest sample size. In addition, storage of at least 50 g is recommended in order to allow homogeneity. Once a soil is frozen, it is very difficult to sub-sample for a repeat analysis. Thus, it is wise to freeze a number of smaller sub-samples. Care should be taken to guarantee the homogeneity when sub-samples are prepared. 6.8 Preparing the samples after storage Appropriate procedures for preparing the samples after storage will depend on the storage conditions and the determinations. It is not possible to give a general specification. Existing standards (e. g. ISO 11464) should be considered. When a non-frozen soil sample is stored for a long period of time, a vertical redistribution of particles may occur. Remixing in a suitable mixer is advisable. For large samples, remixing in a mixer may not be sufficient. Mixing by spreading the sample in a thin layer on a plastic foil, then repeatedly folding the layer and spreading it out again, is recommended. SIST ISO 18512:2018
ISO 18512:2007(E) 6 © ISO 2007 – All rights reserved For frozen samples, thawing conditions shall be defined, as they can influence the determination of biological, microbiological and organic parameters. The samples shall be thawed in their original bags or containers. 7 Stepwise scheme This International Standard is based on a simple stepwise procedure that enables an informed decision on the choice of conditions for storage and preservation which can be considered in advance of the collection of samples in the field. The steps are given below. Step A Consideration of the need for further analysis and duration of storage (Clause 8). Step B Consideration of parameters presently relevant to the study (Clause 9). Step C Consideration of parameters that may be of interest in the future (Clause 10). Step D Consideration of how each of these parameters may be affected by storage conditions (Clause 11). Step E Design of storage conditions to prevent changes in sample properties (Clause 12). Step F Design of documentation and labelling scheme including sample management (Clause 13). Step G Estimation of costs for storage and documentation and comparison of these costs with available or expected funding (Clause 14). 8 Step A: Consideration of need for further analysis and duration of storage If there is no need for further analysis, there is little cause for sample storage. There are many reasons for further analysis which should be considered. Examples: ⎯ resources may not be available at the time of sampling for all the determinations required; ⎯ methods for all the determinations required may not be available at the time of sampling; ⎯ there may be uncertainty in the method chosen which calls for possible further analysis; ⎯ legal requirements for possibility of further analysis may exist; ⎯ expansion of the analytical programme depending on the results of preliminary analyses should be considered. 9 Step B: Consideration of parameters currently relevant to the study The soil properties of interest should be part of the study programme for which the samples have been collected. In order to make an informed decision on the storage conditions, it is important to go through this list of relevant parameters. Existing ISO soil standard parameters should usually be given high priority. 10 Step C: Consideration of parameters which may be of interest in the future The possibility of new parameters being included in the study at a later date should always be considered. SIST ISO 18512:2018
ISO 18512:2007(E) © ISO 2007 – All rights reserved 711 Step D: Consideration of how each of these parameters may be affected by storage conditions 11.1 General The consideration of how each of the parameters defined in Steps B and C may be affected by storage conditions is a critical step. If the number of parameters is large, step D may be time consuming. In monitoring programmes, there may be 50 or more parameters. Grouping of the parameters, as shown in 11.3-11.4, is strongly recommended. This International Standard does not aim to give specific information on the effect of all storage conditions on all possible parameters. The information presented below is a selection based on common requirements. Due to the small number of studies, there is sometimes a lack of scientific evidence on how long-time storage affects the parameters to be measured. General experience has been accumulated in Table A.1 in Annex A. 11.2 Soil characteristics 11.2.1 Electrical conductivity The electrical conductivity reflects the salt content of the soil and should not vary much with time. 11.2.2 pH In air-dried or frozen soil samples, the pH is not expected to change during storage for several years. Studies have shown that no difference in pH could be observed in samples stored for up to 6 months at temperatures between – 18 °C and – 150 °C, liquid nitrogen [7] 11.2.3 Water-holding capacity Freezing may change the water-holding capacity of soil. If the water-holding capacity of the sample after storage is of interest, the value has to be remeasured. 11.2.4 Structural stability Samples taken for assessment of the structural stability of soil cannot be frozen, as freezing disrupts the structure of the soil. If the stability in the field state is required, samples cannot even be dried. On this basis, they should be treated without delay. 11.3 Chemical parameters 11.3.1 Metals and trace elements Provided that the air-dried soil samples have been stored at room temperature in glass containers or in sealed polyethylene bags further protected by dust-tight plastic containers, the storage time is generally at least 7 years for subsequent extraction by quite strong and strong extracting solutions for the determination of the macronutrients K, Mg, Ca and the trace elements As, Be, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, V, Zn. Examples of quite strong and strong extracting solutions are Mehlich 2 and Mehlich 3 extractants, 2 mol/l HNO3 and aqua regia. Cr(VI) is stable for 30 days after sample collection in wet soil at refrigeration. The risk of loss of mercury in elemental form or in volatile compounds shall be considered. When using a weak extracting solution (e.g. 0,01 mol/l CaCl2) the soil samples shall be refrigerated to ensure long-term stability. Some measured extractable nutrient concentrations were found to be changed by storage at elevated temperatures [3]. SIST ISO 18512:2018
ISO 18512:2007(E) 8 © ISO 2007 – All rights reserved 11.3.2 Total nitrogen and nitrogen compounds Nitrogen in soil appears in inorganic forms, mainly nitrate and ammonium ions, and in organic forms as organic compounds, some of which are a part of the microbial soil biomass. The dynamic balance between these forms cause a major problem when storing soil samples for determination of nitrogen and its compounds. The most significant factor affecting this balance is the soil biological activity that is dependent on the aeration, temperature and humidity of the soil. All these parameters may vary during the sampling, transport, sample treatment, etc., and the determined concentrations of the individual nitrogen forms may not be relevant to the actual concentrations at the sampling site. To reduce the risk for changes in the inorganic forms of nitrogen, the samples should be kept
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NORME ISO
INTERNATIONALE 18512
Première édition
2007-08-15
Qualité du sol — Lignes directrices
relatives au stockage des échantillons
de sol à long et à court termes
Soil quality — Guidance on long and short term storage of soil samples
Numéro de référence
ISO 18512:2007(F)
©
ISO 2007
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ISO 18512:2007(F)
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ISO 18512:2007(F)
Sommaire Page
Avant-propos. iv
Introduction . v
1 Domaine d'application. 1
2 Références normatives. 1
3 Termes et définitions. 3
4 Observations générales sur le stockage des échantillons de sol. 3
5 Évolution des propriétés du sol lors du stockage . 4
6 Conditions de stockage . 4
6.1 Généralités. 4
6.2 Lumière. 4
6.3 Température. 5
6.4 Humidité. 5
6.5 Accessibilité, sécurité, documentation et contrôle qualité. 5
6.6 Durée du stockage. 5
6.7 Conteneurs et quantité d’échantillon stocké. 6
6.8 Préparation des échantillons après un stockage.6
7 Démarche par étapes. 6
8 Étape A: Déterminer le besoin d’analyses complémentaires et la durée de stockage . 7
9 Étape B: Déterminer les paramètres actuellement pertinents pour l’étude . 7
10 Étape C: Déterminer les paramètres susceptibles de présenter un intérêt dans le futur. 7
11 Étape D: Déterminer l’impact éventuel des conditions de stockage sur chaque paramètre. 7
11.1 Généralités. 7
11.2 Caractéristiques du sol. 8
11.3 Paramètres chimiques. 8
11.4 Essais biologiques. 11
12 Étape E: Concevoir des conditions de stockage qui préservent les propriétés des
échantillons . 13
13 Étape F: Concevoir un programme de documentation et d’étiquetage incluant la gestion
des échantillons. 13
14 Étape G: Estimer les coûts du stockage et de la documentation et les comparer au
financement disponible ou attendu . 13
15 Rapport d’essai . 13
Annexe A (normative) Conditions de stockage recommandées pour les échantillons de sol . 14
Bibliographie . 17
© ISO 2007 – Tous droits réservés iii
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ISO 18512:2007(F)
Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes nationaux de
normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est en général confiée
aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude a le droit de faire partie du
comité technique créé à cet effet. Les organisations internationales, gouvernementales et non
gouvernementales, en liaison avec l'ISO participent également aux travaux. L'ISO collabore étroitement avec
la Commission électrotechnique internationale (CEI) en ce qui concerne la normalisation électrotechnique.
Les Normes internationales sont rédigées conformément aux règles données dans les Directives ISO/CEI,
Partie 2.
La tâche principale des comités techniques est d'élaborer les Normes internationales. Les projets de Normes
internationales adoptés par les comités techniques sont soumis aux comités membres pour vote. Leur
publication comme Normes internationales requiert l'approbation de 75 % au moins des comités membres
votants.
L'attention est appelée sur le fait que certains des éléments du présent document peuvent faire l'objet de
droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable de ne
pas avoir identifié de tels droits de propriété et averti de leur existence.
L'ISO 18512 a été élaborée par le comité technique ISO/TC 190, Qualité du sol, sous-comité SC 2,
Échantillonnage.
iv © ISO 2007 – Tous droits réservés
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ISO 18512:2007(F)
Introduction
De nombreux programmes de recherche sur les sols imposent de conserver les échantillons de sol en vue
d’une exploitation ultérieure. Le choix des conditions de stockage détermine la possibilité d’utiliser les
échantillons pour des usages futurs. La présente Norme internationale donne des lignes directrices pour
choisir les conditions de stockage des échantillons de sol.
© ISO 2007 – Tous droits réservés v
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NORME INTERNATIONALE ISO 18512:2007(F)
Qualité du sol — Lignes directrices relatives au stockage
des échantillons de sol à long et à court termes
1 Domaine d'application
La présente Norme internationale donne des lignes directrices relatives au stockage et à la conservation des
échantillons de sol destinés aux déterminations de laboratoire, ainsi qu’à leur préparation en vue d’une
analyse après stockage. Une attention toute particulière est portée aux durées maximales de stockage en
fonction des différentes conditions de conservation.
2 Références normatives
Les documents de référence suivants sont indispensables pour l'application du présent document. Pour les
références datées, seule l'édition citée s'applique. Pour les références non datées, la dernière édition du
document de référence s'applique (y compris les éventuels amendements).
EN 15192:2006, Caractérisation des déchets et des sols — Dosage du chrome(VI) dans les matériaux solides
par digestion alcaline et chromatographie ionique avec détection spectrophotométrique
ISO 10301, Qualité de l'eau — Dosage des hydrocarbures halogénés hautement volatils — Méthodes par
chromatographie en phase gazeuse
ISO 10381-6, Qualité du sol — Échantillonnage — Partie 6: Lignes directrices pour la collecte, la manipulation
et la conservation, dans des conditions aérobies, de sols destinés à une étude en laboratoire des processus,
de la biomasse et de la diversité microbiens
ISO 10382, Qualité du sol — Dosage des pesticides organochlorés et des biphényles polychlorés — Méthode
par chromatographie en phase gazeuse avec détection par capture d'électrons
ISO 10390, Qualité du sol — Détermination du pH
ISO 10694, Qualité du sol — Dosage du carbone organique et du carbone total après combustion sèche
(analyse élémentaire)
ISO 11048, Qualité du sol — Dosage du sulfate soluble dans l'eau et dans l'acide
ISO 11074, Qualité du sol — Vocabulaire
ISO 11259, Qualité du sol — Description simplifiée du sol
ISO 11261, Qualité du sol — Dosage de l'azote total — Méthode de Kjeldahl modifiée
ISO 11263, Qualité du sol — Dosage du phosphore — Dosage spectrométrique du phosphore soluble dans
une solution d'hydrogénocarbonate de sodium
ISO 11265, Qualité du sol — Détermination de la conductivité électrique spécifique
ISO 11266, Qualité du sol — Lignes directrices relatives aux essais en laboratoire pour la biodégradation de
produits chimiques organiques dans le sol sous conditions aérobies
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ISO 18512:2007(F)
ISO 11267, Qualité du sol — Inhibition de la reproduction de Collembola (Folsomia candida) par des polluants
du sol
ISO 11268-1, Qualité du sol — Effets des polluants vis-à-vis des vers de terre (Eisenia fetida) — Partie 1:
Détermination de la toxicité aiguë en utilisant des substrats de sol artificiel
ISO 11268-2, Qualité du sol — Effets des polluants vis-à-vis des vers de terre (Eisenia fetida) — Partie 2:
Détermination des effets sur la reproduction
ISO 11466, Qualité du sol — Extraction des éléments en traces solubles dans l'eau régale
ISO 13877, Qualité du sol — Dosage des hydrocarbures aromatiques polycycliques — Méthode par
chromatographie en phase liquide à haute performance
ISO 13878, Qualité du sol — Détermination de la teneur totale en azote par combustion sèche («analyse
élémentaire»)
ISO 14154, Qualité du sol — Dosage de certains chlorophénols — Méthode de chromatographie en phase
gazeuse avec détection par capture d'électrons
ISO 14238, Qualité du sol — Méthodes biologiques — Détermination de la minéralisation de l'azote et de la
nitrification dans les sols, et de l'influence des produits chimiques sur ces processus
ISO 14240-1, Qualité du sol — Détermination de la biomasse microbienne du sol — Partie 1: Méthode par
respiration induite par le substrat
ISO 14240-2, Qualité du sol — Détermination de la biomasse microbienne du sol — Partie 2: Méthode par
fumigation-extraction
ISO 14255, Qualité du sol — Détermination de l'azote nitrique, de l'azote ammoniacal et de l'azote soluble
total dans les sols séchés à l'air en utilisant le chlorure de calcium comme solution d'extraction
ISO/TS 14256-1, Qualité du sol — Dosage des nitrates, nitrites et de l'ammonium dans les sols humides par
extraction avec une solution de chlorure de potassium — Partie 1: Méthode manuelle
ISO 14507, Qualité du sol — Prétraitement des échantillons pour la détermination des contaminants
organiques
ISO 15009, Qualité du sol — Détermination par chromatographie en phase gazeuse des teneurs en
hydrocarbures aromatiques volatils, en naphthalène et en hydrocarbures halogénés volatils — Méthode par
purge et piégeage avec désorption thermique
ISO 15473, Qualité du sol — Lignes directrices relatives aux essais en laboratoire pour la biodégradation de
produits chimiques organiques dans le sol sous conditions anaérobies
ISO 15685, Qualité du sol — Détermination de la nitrification potentielle et inhibition de la nitrification — Essai
rapide par oxydation de l'ammonium
ISO 15799, Qualité du sol — Lignes directrices relatives à la caractérisation écotoxicologique des sols et des
matériaux du sol
ISO 15903, Qualité du sol — Format d'enregistrement des données relatives aux sols et aux sites
ISO 15952, Qualité du sol — Effets des polluants vis-à-vis des escargots juvéniles (Helicidae) —
Détermination des effets sur la croissance par contamination du sol
ISO 16072, Qualité du sol — Méthodes de laboratoire pour la détermination de la respiration microbienne du
sol
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ISO 18512:2007(F)
ISO 16387, Qualité du sol — Effets des polluants sur les Enchytraeidae (Enchytraeus sp.) — Détermination
des effets sur la reproduction et la survie
ISO 16703, Qualité du sol — Dosage des hydrocarbures de C10 à C40 par chromatographie en phase
gazeuse
ISO 17155, Qualité du sol — Détermination de l'abondance et de l'activité de la microflore du sol à l'aide de
courbes de respiration
ISO 20963, Qualité du sol — Effets des polluants vis-à-vis des larves d'insectes (Oxythyrea funesta) —
Détermination de la toxicité aiguë
ISO 22030, Qualité du sol — Méthodes biologiques — Toxicité chronique sur les plantes supérieures
ISO 22155, Qualité du sol — Dosage des hydrocarbures aromatiques et halogénés volatils et de certains
éthers par chromatographie en phase gazeuse — Méthode par espace de tête statique
ISO 23753-1, Qualité du sol — Détermination de l'activité des déshydrogénases dans les sols — Partie 1:
Méthode au chlorure de triphényltétrazolium (CTT)
ISO 23753-2, Qualité du sol — Détermination de l'activité des déshydrogénases dans les sols — Partie 2:
Méthode au chlorure de iodotétrazolium (CIT)
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions donnés dans l’ISO 11074 et l’ISO 11259
s'appliquent.
Dans la présente Norme internationale, le terme «réfrigération» désigne une température de 4 °C ± 2 °C. Le
terme «congélation» indique une température inférieure à −18 °C.
4 Observations générales sur le stockage des échantillons de sol
De nombreuses études nécessitent de recueillir des échantillons sur le terrain afin de déterminer au
laboratoire diverses propriétés. En général, les échantillons sont prélevés sur le site étudié, sont mélangés ou
traités sur le site, placés dans des conteneurs puis transportés jusqu’au laboratoire où ils peuvent de nouveau
subir un traitement avant d’être analysés. Certains échantillons peuvent être stockés en l’état en vue d’une
analyse ultérieure. Après l’analyse, le reste des échantillons peut être éliminé ou stocké. Les échantillons sont
stockés lorsqu’une analyse ultérieure est requise, soit pour vérifier des paramètres déjà déterminés, soit en
vue de futures déterminations complémentaires.
Dans la pratique, le stockage des échantillons est pertinent dans les deux situations suivantes:
⎯ les essais de routine (par exemple réalisés par des laboratoires environnementaux) au cours desquels
les échantillons de sol sont généralement stockés quelques semaines après leur prélèvement afin
d’effectuer des essais complémentaires ou pour confirmer des résultats antérieurs;
⎯ les stockages prolongés, parfois sur plusieurs décennies, par exemple dans le cadre de programmes de
surveillance, de matériaux de référence ou de programmes de recherche dans lesquels la dégradation
est évaluée.
Ces deux situations entrent dans le champ d’application de la présente Norme internationale.
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Il convient de choisir soigneusement les conditions de stockage à toutes les étapes et ce, dès le prélèvement
de l’échantillon. Dans la mesure où un retard imprévu dans le transport peut se produire, il convient
d’appliquer les présentes lignes directrices même si la durée de transport prévue est courte. Les conditions de
stockage à prendre en compte sont, par exemple, la luminosité, la température, l’humidité, l’accessibilité, la
durée de stockage, le type de conteneur et la quantité d’échantillon à conserver. Il est aussi important d’établir
une documentation sur les échantillons et leurs conditions de stockage. Il convient également de tenir compte
des risques et des problèmes de sécurité. Pour les études à grande échelle (dans le cadre d'un programme
de surveillance, par exemple), la conception des conditions de stockage est particulièrement importante car le
nombre d’échantillons peut considérablement croître au fil des ans. Des conditions de stockage inadaptées
peuvent accroître les coûts et rendre les échantillons impropres à une future utilisation.
L’effet du stockage sur la biodiversité a uniquement été pris en compte par rapport à la diversité
microbiologique.
Il convient de tenir compte des variations de radioactivité dues à des pertes ou des gains de matières
radioactives liés aux composés respectifs. La présente Norme internationale ne couvre pas la décroissance
de la radioactivité car le stockage n’a généralement aucun d’impact sur celle-ci.
5 Évolution des propriétés du sol lors du stockage
Il est utile d’examiner les principaux phénomènes biologiques, chimiques et physiques susceptibles
d’engendrer des changements dans les échantillons:
⎯ la variation de la teneur en eau;
⎯ l’activité biologique;
⎯ l’évaporation ou la précipitation des substances volatiles;
⎯ les réactions chimiques avec l’atmosphère;
⎯ les réactions avec le conteneur d’échantillon.
Des variations inacceptables des paramètres du sol peuvent se produire si ces phénomènes ne sont pas
contrôlés au moyen de conditions de stockage choisies de manière appropriée. Cependant, le contrôle de
tous ces phénomènes pour l‘ensemble des échantillons, sur une longue période peut s’avérer très coûteux,
voire impossible. Il est donc important de concevoir des conditions de stockage adaptées aux objectifs de
l’étude.
Il est utile de noter que le mesurage de certains paramètres (la teneur en certaines substances volatiles, par
exemple) peut être impossible à l’issue de la période de stockage et ce, quelles que soient les conditions de
stockage. Dans ces cas, il est recommandé d’examiner sérieusement, dès le début, la nécessité d’acquérir
des données sur ces paramètres et d'adapter le programme d'analyse en conséquence.
6 Conditions de stockage
6.1 Généralités
Cet article dresse une liste des conditions de stockage qui doivent être déterminées lors de la conception du
programme de stockage.
6.2 Lumière
Les conditions de luminosité ont un impact sur la teneur de certaines substances, particulièrement pour les
organiques. Il convient de les prendre en compte en utilisant, par exemple, des flacons en verre brun ou en
maintenant les échantillons dans l’obscurité complète.
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6.3 Température
Le choix de la température est toujours très important car ce facteur a un impact sur l’activité biologique des
échantillons. Il s’agit donc d’un facteur majeur lors de la conception d’une installation de stockage. Dans
certains cas, la température ambiante conviendra mais souvent une réfrigération ou une congélation pourra
être requise pour réduire l’activité biologique. Dans des cas très spéciaux, la conservation à la température de
l’azote liquide sera nécessaire.
Il convient d’examiner le besoin de stocker quelques échantillons à une température de –80 °C ou en deçà
(par exemple des échantillons de référence de qualité supérieure) afin de démontrer si les échantillons
stockés à basse température restent stables.
6.4 Humidité
L’humidité entraînera des variations de l’activité microbiologique ou des changements chimiques dans les
échantillons de sol, à moins que la température ne soit très basse. Il est donc important de contrôler
l’humidité.
Si les échantillons ne sont pas conservés dans des conteneurs étanches à l’air, l’installation de stockage doit
être maintenue à un faible taux d’humidité tout au long de l’année.
Si les conteneurs utilisés sont étanches à l’air, l’humidité des échantillons restera constante pendant toute la
durée du stockage. Dans ce cas, il est nécessaire de vérifier que l’humidité initiale des échantillons est
suffisamment faible pour inhiber l’activité microbiologique.
6.5 Accessibilité, sécurité, documentation et contrôle qualité
En cas d’analyse urgente ou répétée des échantillons, il convient que l’installation de stockage soit facilement
accessible à partir du laboratoire, afin de réduire la durée et le risque de dégradation de la qualité lors du
transfert jusqu’au laboratoire.
Il est également important de tenir compte des problèmes de sécurité (incendie, vol et destruction, par
exemple), notamment pour les échantillons de grande valeur.
La documentation (voir l’ISO 15903), l’étiquetage correct et l’élimination de la contamination croisée sont
d’autres problèmes de sécurité à résoudre.
Il convient de toujours considérer comme dangereux les échantillons provenant de terrains contaminés, et de
les manipuler en conséquence.
Il est recommandé de mettre en place un programme de contrôle qualité pertinent. Un échantillon de
référence (certifié) peut être utilisé, ou un ou plusieurs échantillons fraîchement prélevés peuvent faire l’objet
d’une analyse préalable.
6.6 Durée du stockage
La durée de stockage nécessaire est un élément important des conditions de stockage. Comme indiqué à
l’Article 4, certains échantillons sont conservés pendant seulement quelques semaines (pour des essais
environnementaux de routine, par exemple), alors que d’autres le sont sur une plus longue période. Des
échantillons de sol «de référence», bien documentés et prélevés à intervalles réguliers sur plusieurs années,
pourraient être utilisés pour déterminer la magnitude de tout changement dans des propriétés importantes du
sol. La durée de stockage peut également être soumise à des prescriptions légales.
Il convient de toujours évaluer la nécessité d'une longue durée de stockage en fonction du coût du stockage
et de la documentation.
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6.7 Conteneurs et quantité d’échantillon stocké
Il convient de choisir soigneusement les conteneurs par rapport à la nature de sa composition, son étanchéité
et sa taille. Il est également recommandé de valider des propriétés importantes (par exemple la protection
contre la contamination et la capacité à protéger l’échantillon de la lumière ou l'air). Des modes opératoires
appropriés doivent être appliqués pour le nettoyage ou la stérilisation.
De nombreux conteneurs en matière plastique étant fragilisés après cinq à dix ans d’utilisation, les conteneurs
en verre sont préférés. Cependant, si la teneur en eau des échantillons est importante (échantillons argileux
par exemple), le verre peut se fissurer lors de la congélation. Ce risque de fissuration peut être réduit en
remplissant partiellement les flacons.
Il convient d’examiner la quantité d’échantillon à stocker. La quantité requise dépend des déterminations
programmées et peut s’avérer difficile à calculer. Il est prudent de stocker une quantité de matériau suffisante
pour réaliser au moins cinq déterminations du paramètre nécessitant la taille d’échantillon maximale, à moins
que ce matériau ne soit très coûteux ou qu’une nouvelle analyse soit très peu probable. De plus, il est
recommandé de stocker au moins 50 g afin de garantir l’homogénéité.
Le sol étant congelé, il est très difficile d’en prélever des sous-échantillons en vue de répéter une analyse. Il
est donc prudent de congeler un certain nombre de sous-échantillons de plus petite taille. Si des sous-
échantillons sont préparés, il convient de garantir leur homogénéité.
6.8 Préparation des échantillons après un stockage
Les modes opératoires appropriés pour préparer les échantillons stockés dépendront des conditions de
stockage et des déterminations à effectuer. Il est impossible d’exposer une spécification à caractère général.
Il convient de considérer les normes existantes (l’ISO 11464 par exemple).
Si un échantillon non congelé est stocké pendant une période prolongée, une redistribution verticale de ses
particules peut avoir lieu. Il est conseillé de mélanger de nouveau l’échantillon dans un mélangeur adapté.
Pour les échantillons de grande taille, le mélange peut être impossible ou insuffisant. Il est alors recommandé
d’étaler l’échantillon en une couche fine sur un film plastique, puis de plier plusieurs fois la couche et de
l’étaler de nouveau.
Pour les échantillons congelés, les conditions de décongélation doivent être définies car elles peuvent avoir
un impact sur la détermination des paramètres biologiques, microbiologiques et organiques. Les échantillons
doivent être décongelés dans leurs sacs ou conteneurs d'origine.
7 Démarche par étapes
La présente Norme internationale est basée sur un mode opératoire simple, organisé en plusieurs étapes, qui
permet de prendre une décision avisée pour choisir les conditions de stockage et de conservation qui peuvent
être prises en considération avant le prélèvement des échantillons sur le terrain.
Ces étapes sont exposées ci-dessous.
Étape A Déterminer le besoin d’analyses complémentaires et la durée de stockage (Article 8).
Étape B Déterminer les paramètres actuellement pertinents pour l’étude (Article 9).
Étape C Déterminer les paramètres susceptibles de présenter un intérêt dans le futur (Article 10).
Étape D Déterminer l’impact éventuel des conditions de stockage sur chaque paramètre (Article 11).
Étape E Concevoir des conditions de stockage évitant l’évolution des propriétés des échantillons (Article 12).
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Étape F Concevoir un programme de documentation et d’étiquetage pour la gestion des échantillons
(Article 13).
Étape G Estimer les coûts du stockage et de la documentation et les comparer au financement disponible ou
attendu (Article 14).
8 Étape A: Déterminer le besoin d’analyses complémentaires et la durée
de stockage
Si aucune analyse complémentaire n’est nécessaire, les échantillons n’ont pas lieu d’être stockés. Il convient
d'examiner les nombreuses raisons pouvant justifier une analyse complémentaire. Exemples:
⎯ au moment de l’échantillonnage, les ressources peuvent ne pas être disponibles pour toutes les
déterminations requises;
⎯ lors de l’échantillonnage, les méthodes requises pour toutes les déterminations peuvent également ne
pas être disponibles;
⎯ une incertitude peut subsister sur la méthode choisie, d’où l’éventuelle nécessité d’une analyse
complémentaire;
⎯ des prescriptions légales peuvent imposer une analyse complémentaire;
⎯ il convient d'envisager l’extension du programme analytique en fonction des résultats des analyses
préliminaires.
9 Étape B: Déterminer les paramètres actuellement pertinents pour l’étude
Il convient d’intégrer les propriétés de sol ayant un intérêt dans le programme de recherche pour lequel les
échantillons ont été prélevés. Pour prendre une décision avisée sur les conditions de stockage, il est
important de passer en revue cette liste de paramètres pertinents.
Il est généralement recommandé de donner la priorité aux paramètres des normes ISO existantes relatives au
sol.
10 Étape C: Déterminer les paramètres susceptibles de présenter un intérêt
dans le futur
Il convient de toujours examiner la poss
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