Soil quality - Guidance on sampling techniques
土壤质量 土壤采样技术指南
1 Scope
The standard gives guidance on techniques for taking and storing soil samples so that these can subsequently be examined for the purpose of providing information on soil quality.
This standard gives information on typical equipment that is applicable in particular sampling situations to enable correct sampling procedures to be carried out and representative samples to be collected. Guidance is given on the selection of the equipment and the techniques to use to enable both disturbed and undisturbed samples to be correctly taken at different depths.
The guidance provided is intended to assist in the collection of samples for soil quality for agricultural purposes and also provide guidance for the collection of samples for contamination investigations which will require different techniques and skills.
This standard makes reference to some aspects of the collection of samples of groundwater and soil gas as part of a soil sampling programme.
This standard specifically does not cover investigations for geotechnical purposes, though where redevelopment of a site is envisaged the soil quality investigation and the geotechnical investigation may be beneficially combined.
This standard is not applicable to the sampling of hard strata such as bedrock.
Techniques to collect information on soil quality without taking samples, such as geophysical methods, are not covered by this standard.
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.
ISO 11074-1 Soil Quality - Vocabulary - Part 1: Terms and Definitions Relating to the Protection and Pollution of the Soil
ISO 11074-2 Soil Quality - Vocabulary - Part 2: Terms and Definitions Relating to Sampling
ISO 11074-4 Soil Quality- Vocabulary - Part 4: Terms and Definitions Related to Rehabilitation of Soil and Sites
3 Terms and Definitions
For the purposes of this document, the terms and definitions in ISO 11074-1, ISO 11074-2, ISO 11074-4 and the following apply.
3.1 Spot Sample; Single Sample
sample of material collected from a single point
Note: This may be a disturbed or undisturbed sample.
3.2 Slot Sample
sample taken as a vertical slot from within a stratum or other subpart which is putatively homogeneous
Note: This is a disturbed sample.
3.3 Stratified Sample
sample obtained as a combination of spot samples from strata or subparts, putatively homogeneous
Note: This is a disturbed sample.
3.4 Cluster Sample
sample which is a composite of small incremental point samples taken close together
Note: This is a disturbed sample.
3.5 Spatial Sample
sample which is a composite of small incremental point samples taken over an area (such as a field)
Note: This is a disturbed sample.
4 Principle
4.1 Sampling of Soil
Soil samples are collected and examined primarily to determine associated physical, chemical, biological and radiological parameters. This chapter outlines the more general factors to be considered when selecting sampling equipment and its use. More detailed information is given in subsequent chapters.
Whenever a volume of soil is to be characterized, it is generally impossible to examine the whole and it is therefore necessary to take samples. The samples collected need to be as fully representative as possible of the whole to be characterized, and all precautions should be taken to ensure that, as far as possible, the samples do not undergo any changes in the interval between sampling and analysis. The samples normally collected are described as disturbed samples, i.e. the soil particles become loosened and separated in the sampling process. If it is necessary to collect undisturbed samples, e.g. for microbiological or geotechnical purposes, the samples need to be collected in such a manner that the soil particles and pore structure remain unaltered in comparison with the original ground structure. The sampling of multiphase systems, such as soils containing water or gases which are not of natural origin (e.g. waste materials), can present special problems.
The sampling technique should be selected to enable the collection of samples of ground material which can be presented to the laboratory for examination or analysis to establish basic information on the pedology and distribution of naturally occurring or manmade soils, their chemical, mineralogical and biological composition, and their physical properties at selected locations.
The choice of sampling technique depends, in addition, on the required precision of the results, which in turn depends on the ranges of concentration of components, the sampling procedures and the type of analysis.
Sampling equipment should be carefully selected in relation to the different materials which may be present in the ground and the analysis to be carried out. Utmost care should be taken to avoid cross-contamination, loss of volatile compounds, change of composition due to exposure to air, and other changes which may occur between sampling and the testing of the sample.
Every soil sampling technique usually consists of two separate steps:
a) gaining access to the point of sampling (removing the cover or sealing, digging or drilling a hole to reach the desired depth of sampling), and
b) taking the soil sample.
Both steps depend on each other and both shall meet the requirements of the sampling principles.
4.2 Sampling of Water
Soil investigation programmes, particularly those carried out at contaminated sites, may also require water samples to be taken. These should be collected in accordance with appropriate International Standards on ground or surface water sampling with regard to ground investigation. For further information see ISO 10381-1.
4.3 Sampling of Soil Gas
Ground investigation programmes may involve assessment of soil gas composition for typical landfill gas components such as methane and carbon dioxide. In the case of contaminated sites, the suspected presence of solvents or fuels may require investigation. An International Standard (ISO 10381-7) is in the course of preparation to cover such investigations, and some indicative guidance is incorporated in this standard.
5 Choice of Sampling Technique
5.1 Preliminary Information
The choice of sampling technique, the selection of the sampling equipment and the method of taking soil samples depends upon the objectives of the sampling, the strata to be sampled, the nature of possible contamination, and the examination or analysis to be carried out on the samples.
Thus certain information is needed to make this choice. This information may include:
- the size and topography of the area to be sampled;
- the nature of the ground to be sampled;
- some indication of the possible lateral and vertical variations of soil type or strata;
- the geology of the site and surrounding area;
- the depth to groundwater and its direction of flow;
- the depths from which samples are to be taken, taking into consideration the future use of the site, including depth of excavations or foundations;
- previous usage or treatment of the site;
- the presence of buildings and obstructions, such as foundations or hardstandings, buried tanks and underground services (e.g. electricity, sewers, mains, cables);
- indications of the presence of underground tanks and service (for example inspection covers, inspection chambers, vent pipes);
- the presence of concrete or tarmac pathways, roadways or hardstandings;
- the safety of the site personnel and protection of the environment;
- the growth of vegetation leading to extensive root development;
- the presence of unexpected surface-water pools or water-saturated ground;
- the presence of fences, walls or earthworks designed to prevent access to the site;
- the presence of tipped material above the level of the site, or material from the demolition of buildings;
- location of water bodies at risk from contamination, including surface and groundwater.
Extreme natural circumstances, such as permafrost, laterization, calcrete or other indurations, may occur which require special techniques in order to obtain samples. This shall be known prior to the design of a sampling programme.
To collect this information, a desk study or preliminary survey of the site is strongly recommended. When investigating soils suspected of contamination, the preliminary survey is an essential part of the investigation programme [see Chapter 6 of ISO 10381-1 and Chapter 6 of ISO 10381-5]. Its main relevant concerns are:
a) to ensure an investigation which is both technically and cost effective;
b) to ensure the safety of personnel and to protect the environment.
The preliminary survey may comprise both desktop studies and site reconnaissance (field work). It does not normally include taking samples, but in some circumstances limited sampling may be useful in relation to determining the parameters for the site investigation, investigating some metholodical aspects, and identifying possible hazards to the investigating personnel.
Foreword I
1 Scope
2 Normative References
3 Terms and Definitions
3.1 Spot Sample; Single Sample
3.2 Slot Sample
3.3 Stratified Sample
3.4 Cluster Sample
3.5 Spatial Sample
4 Principle
4.1 Sampling of Soil
4.2 Sampling of Water
4.3 Sampling of Soil Gas
5 Choice of Sampling Technique
5.1 Preliminary Information
5.2 Type of Sample
5.3 Selection of Sampling Technique
5.4 Cross-contamination
6 Safety and Environmental Protection in the Investigation
6.1 Personal Protection
6.2 Protection of Buildings and Installations
6.3 Environmental Protection
6.4 Backfilling
7 Techniques
7.1 General
7.2 Cross-contamination
7.3 Undisturbed Samples
8 Storage of Samples
8.1 General
8.2 Sample Containers
8.3 Labelling
8.4 Sample Storage
9 Sampling Report
Appendix A (Informative) Manually and Power-operated Sampling Tools
Bibliography
