Microsoft Word C032424e doc Reference number ISO 10381 2 2002(E) © ISO 2002 INTERNATIONAL STANDARD ISO 10381 2 First edition 2002 11 01 Soil quality — Sampling — Part 2 Guidance on sampling techniques[.]
Sampling of soil
Soil sampling involves collecting and analyzing samples to assess physical, chemical, biological, and radiological parameters, providing a comprehensive understanding of soil conditions When selecting sampling equipment, it is essential to consider these parameters to ensure accurate and representative results Detailed guidelines for equipment selection and usage are outlined in subsequent sections to support effective soil analysis.
When characterizing a soil volume, it is essential to collect representative samples, as examining the entire volume is usually impractical Samples should accurately reflect the whole and be preserved from changes between collection and analysis to ensure reliable results Disturbed samples, where soil particles are loosened during sampling, are commonly used, but undisturbed samples are necessary for microbiological or geotechnical studies to maintain the original soil structure Sampling soils containing water or gases, such as waste materials, presents additional challenges due to their complex, multiphase nature.
Selecting an appropriate sampling technique is essential for collecting ground material samples suitable for laboratory analysis These samples help determine important information about soil pedology, distribution of natural and manmade soils, as well as their chemical, mineralogical, biological, and physical properties at specific locations Proper sampling ensures accurate assessment of soil composition and supports informed land management and environmental studies.
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The selection of a sampling technique is influenced by the desired precision of results, which is determined by factors such as the concentration ranges of components, sampling procedures, and the type of analysis conducted.
Selecting appropriate sampling equipment is essential to accurately represent various ground materials and ensure reliable analysis Careful handling is crucial to prevent cross-contamination, loss of volatile compounds, and alterations in sample composition caused by air exposure or delays between sampling and testing Proper equipment choice and meticulous procedures help maintain sample integrity and ensure accurate results in ground material analysis.
Soil sampling techniques typically involve two essential steps: first, accessing the sampling point by removing covers, seals, or drilling to reach the desired depth; second, collecting the soil sample accurately Proper execution of these steps ensures reliable laboratory analysis and optimal soil health assessment.
Both steps depend on each other and both shall meet the requirements of the sampling principles.
Sampling of water
Soil investigation programs at contaminated sites often require water sampling to assess groundwater quality Water samples should be collected following international standards, such as ISO 10381-1, to ensure accurate and reliable results Adhering to these protocols is essential for comprehensive site assessment and environmental safety.
Sampling of soil gas
Ground investigation programmes often include analyzing soil gas composition to detect typical landfill gases like methane and carbon dioxide For contaminated sites, investigations may additionally focus on identifying the presence of solvents or fuels An upcoming International Standard (ISO 10381-7) is being developed to provide comprehensive guidance for such investigations, with relevant recommendations already incorporated into this section of ISO 10381.
Preliminary information
Selecting the appropriate sampling technique, equipment, and method is essential and depends on the sampling objectives, the specific strata to be sampled, the nature of potential contamination, and the intended analysis These factors ensure accurate and representative soil samples for reliable examination and assessment.
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 ground water
Extreme natural conditions, such as permafrost, laterization, calcrete, or other indurations, can pose challenges for sampling and require specialized techniques Identifying these conditions beforehand is essential for effective sampling program design, ensuring accurate and reliable sample collection in difficult terrains.
Conducting a desk study or preliminary site survey is essential for collecting accurate information on soil conditions When investigating potentially contaminated soils, this initial survey plays a crucial role in guiding the investigation process, aligning with ISO 10381-1 and ISO 10381-5 standards Its primary objectives are to ensure the investigation is both technically sound and cost-effective, while also safeguarding personnel safety and protecting the environment.
The preliminary survey typically involves desktop studies and site reconnaissance (fieldwork) to assess the area While it generally does not include sampling, limited sampling may be conducted in certain cases to determine key parameters for the site investigation, examine methodological considerations, and identify potential hazards to personnel.
Type of sample
There are two primary types of soil samples used for ground investigation: disturbed samples and undisturbed samples Disturbed samples are collected without preserving the soil structure, meaning soil particles are gathered loosely and can move freely In contrast, undisturbed samples are obtained using specialized equipment that maintains the original soil structure, preserving particle arrangement and void distribution Proper selection between these sample types is essential for accurate soil analysis and geotechnical assessments.
Disturbed samples are suitable for most testing purposes; however, for specific physical measurements, profiling, and microbiological examinations, undisturbed samples are essential Undisturbed sampling is particularly important when analyzing the presence and concentration of volatile organic compounds (VOCs), as disturbance can lead to the loss of these compounds into the atmosphere, compromising accurate results.
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For undisturbed soil samples, tools such as Kubiena boxes, coring tools, or coring cylinders can be used These devices are inserted into the soil and carefully withdrawn, ensuring the sample is preserved in its original physical structure This method is ideal for obtaining high-quality, undisturbed samples necessary for accurate soil analysis.
There are different methods of taking samples from the ground for the purpose of investigating soil quality (see clause 3)
When collecting soil samples, a small slot sample may be mistaken for a spot sample, but most sampling methods generate composite or aggregate samples These composite samples are averaged and may not accurately reflect changes in soil characteristics that occur during the sampling process, such as the concentration of volatile compounds Additionally, composite samples are unsuitable for detecting peak concentrations of substances or analyzing variations in soil properties, making them less ideal for specific analytical purposes.
Spot samples are easily collected using hand augers and similar techniques, enabling quick and efficient sampling For undisturbed samples that preserve the original ground structure, specialized equipment is essential to ensure minimal disturbance during collection.
Cluster samples are ideal for ground excavation processes using machinery, as they ensure representative sampling from the excavated material These samples should be collected by taking portions from various points within the excavator bucket, such as a nine-point sampling method, to achieve accurate and consistent results Using cluster sampling in this context enhances the reliability of soil analysis and ensures the sample reflects the overall ground conditions Properly collected cluster samples are essential for precise geotechnical assessments and construction planning.
Spatial or composite samples can be collected using hand or powered augers, with careful attention to ensure the auger consistently retrieves the same sample volume Proper sampling techniques are essential for obtaining reliable and representative data Using consistent sampling methods helps maintain the accuracy and integrity of the sample for analysis.
Selection of sampling technique
This International Standard emphasizes that a single sampling technique cannot be universally applied to all sampling objectives, as there are numerous objectives that can be achieved through different methods Consequently, selecting the appropriate sampling technique depends on the specific goal of the study To ensure effective sampling, it is essential to follow established guidelines and best practices outlined in the standard These rules are designed to provide clarity and consistency, helping practitioners choose suitable techniques based on their unique sampling objectives.
Soil characteristics that are bound to soil horizons (which are most of them) require horizon-bound (stratified) sampling
To accurately assess spatial variation of soil characteristics, spot sampling is essential However, if the desired precision is low, alternative sampling methods may be acceptable, providing a practical balance between effort and accuracy.
Samples taken to identify the distribution and concentration of particular elements or compounds are normally spot samples, or perhaps slot or cluster samples within the area being examined
Samples taken to assess the overall quality or nature of the ground in an area, e.g for certain agricultural purposes, are spatial samples
Sample size shall be sufficiently large to enable all tests and analyses to be performed
Sample size shall be sufficiently large to represent all soil characteristics of interest
Samples shall not be too large to obscure variations in soil characteristics of interest
Soil characteristics of interest shall not be affected by the sampling process, nor by the transportation and storage of samples
Representative sampling involves combining increments with similar properties into a composite sample based solely on their volume fraction of the original population This approach ensures the sample accurately reflects the characteristics of the entire population, which is essential for reliable analysis Proper sampling techniques are critical for achieving valid results in geotechnical, environmental, and industrial testing By adhering to volume-based proportionality, sampling processes maintain the integrity and representativeness of the collected data.
Cross-contamination shall be avoided, as well as the spread of contaminants
Cross-contamination
Chemical soil properties, in particular, can be changed by the sampling procedure in many ways:
by transmission of substances fixed to sampling equipment or containers;
Uncontrolled transport of soil particles to the sampling point occurs when material drops into the sample from higher up in the borehole during augering, drilling, or sample withdrawal This process can lead to contamination of the sample, affecting accuracy and reliability Proper sampling techniques are essential to prevent soil particle redistribution and ensure representative soil analysis results Controlling soil particle movement during sampling helps maintain the integrity of the sample for precise soil testing and assessment.
by transfer of substances from the sampling device or container;
by loss of volatile compounds, leakage of liquids or mechanical separation;
by contamination with auxiliary substances used to enable or facilitate the sampling (fuels, exhaust fumes, greases, oils, lubricants, glues and others);
by contamination with wind-blown particles, spread liquids or precipitation
Ensuring accurate sampling requires that the method employed does not introduce contamination It is essential that both the sampling system and the equipment materials are inert and compatible with the sample to maintain sample integrity Proper selection of sampling techniques and materials helps prevent contamination, leading to reliable and valid results.
To prevent cross-contamination, sampling equipment must be thoroughly cleaned between uses This is essential even in agricultural settings, where repetitive sampling across a field to create composite samples requires the device to be sanitized after each location Proper cleaning of sampling tools ensures the integrity and accuracy of test results by avoiding the transfer of residual sample parts.
When lubrication is necessary, such as using water to facilitate borehole formation and enable sample collection, it is essential to use only suitable lubricants that do not interfere with sample analysis The chosen lubricant must avoid causing matrix effects or contamination that could compromise analytical results, ensuring the integrity and accuracy of the samples for precise testing.
Only devices with controlled chemical quality and composition should be used to handle samples, such as stainless steel trowels for organic compounds and plastics that do not interfere with heavy metals It is essential that all contact surfaces with samples are free from paint, grease, or any chemical treatments to prevent contamination and ensure accurate results.
Lining the borehole can prevent cross-contamination from material dropping into the sample from higher up the bore
6 Safety and environmental protection in the investigation
Soil sampling typically involves minimal ground disturbance, especially in agricultural lands, woodlands, and semi-natural vegetation areas This limited disturbance generally poses no significant hazard or risk to the environment or surrounding ecosystems.
When investigating highly contaminated sites, it is advisable to use probe holes, boreholes, or similar techniques instead of excavations This approach helps minimize exposure, reduces site disturbance, and limits the potential dispersal of contamination, ensuring more effective and safer site assessment.
If the site surface is visibly contaminated or poses a general environmental risk due to exposure to humans or animals, and there is a potential for dispersal of contaminated dust or water pollution, appropriate precautions must be taken to prevent disturbance and spread during the investigation It is essential to inform the landowners and local authorities to enable the implementation of necessary preventative measures Additionally, all relevant national or local regulations regarding information procedures and obligations should be strictly followed to ensure regulatory compliance and environmental safety.
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Personal protection
During a soil-sampling investigation there are different procedures that may influence human health and safety:
handling sampling instruments and machinery;
unstable ground or slopes, open holes or excavations;
exposure of contaminants to sampling personnel and people living near by or passing by;
exposure of sampling personnel to contaminants released from transport or storage containers or during sample pretreatment;
inconveniences from noise, dust, odours and so on, resulting from heavy fieldwork
When working in areas potentially contaminated with munitions or explosive residues, it is essential to involve a qualified specialist to verify that the site has been thoroughly cleared and rendered safe Ensuring proper clearance before starting any on-site work is crucial for safety and compliance Engage experts to assess and confirm the site’s safety, preventing accidents and ensuring a safe working environment Proper clearance of munitions and explosive residues is vital to minimize risks and facilitate safe construction or operational activities.
When selecting soil sampling methods, it is essential to consider all potential hazardous effects on human health to ensure safe procedures Careful implementation of these methods helps minimize adverse impacts not only on human health but also on other organisms, surrounding environments, and nearby constructions, thereby promoting ecological safety and sustainability.
Protection of buildings and installations
Before starting any intrusive survey, it is crucial to identify the locations of underground services to avoid damage, including plumbing, utility lines, and other subsurface utilities Additionally, overhead cables such as power lines and telecommunications should be precisely located to ensure safety In agricultural surveys, identifying features like irrigation and drainage systems is essential for accurate assessment and planning.
To ensure that service locations and other features that must not be damaged are preserved, consult with the landowner (or tenant) and utility providers Even after identifying service locations, verify sampling sites with a services monitor prior to beginning intrusive investigations If there is uncertainty about the presence of services, manually excavate the top 1.0 to 1.5 meters, or up to the maximum depth of the services, to prevent damage.
Excavation planning must prioritize slope stability and the structural integrity of nearby buildings, while also addressing potential emissions of hazardous substances from contaminated ground In cases where ground issues are suspected, it is advisable to use boreholes or drilling methods rather than traditional excavations to ensure safety and environmental protection.
Environmental protection
Exposed materials on the surface pose environmental hazards through the release of odors, fumes, dust, and contaminated water Dust or polluted water can wash into nearby streams, ponds, or land, making containment challenging To minimize environmental impact, careful work practices are essential during investigation activities, including proper backfilling of trial pits and thorough site cleanup afterward Ensuring these measures are followed helps prevent environmental contamination and protects surrounding ecosystems.
Borehole drilling and construction typically generate minimal arisings that are unlikely to pose disposal issues outside the site These waste materials should be collected and properly disposed of at a suitable location once the investigation is completed.
When the water table is reached, trial pits can fill with contaminated groundwater or non-aqueous fluids such as oils It is essential to exercise special caution during backfilling to prevent the escape or dispersal of these harmful substances onto the site surface or into uncontaminated soil Proper handling and containment strategies are crucial to mitigate environmental risks associated with contaminated fluids in groundwater-filled trial pits.
Open water with contamination or oil sheets poses a danger to waterfowl and other animals
If boreholes are installed or excavations penetrate impermeable strata, e.g clay, new pathways can be created
To prevent contamination spread, boreholes can be drilled down to impermeable strata and sealed with an impermeable plug made of bentonite or similar material This method allows for the insertion of a smaller-diameter inner borehole, enabling deeper drilling while maintaining an effective seal Establishing such a seal ensures that contaminants are contained and do not disperse into the surrounding environment.
Increased dispersal of contamination can occur when beneath an impermeable layer like tarmac or concrete, such as when this layer is breached without proper replacement This can lead to enhanced rainwater infiltration, causing greater percolation and spread of contaminants into soil and groundwater To mitigate this risk, boreholes or excavations should be reinstated with a suitable low-permeability cover layer of appropriate thickness Additionally, a maintenance period should be incorporated into the site investigation plan to address potential settlement of backfilled trial pits, ensuring any settling effects are properly rectified.
Backfilling
Soil-sampling processes create voids that can serve as new migratory pathways, especially in contaminated grounds Large excavations pose safety hazards to both organisms and machinery and can affect the stability of the surrounding soil Unless used for installing monitoring devices, profiling, or foundations, these excavations typically need to be refilled to restore ground integrity and prevent environmental or structural issues.
When backfilling trial pits, it is essential to use excavated material carefully, returning it to its original depth while ensuring any suspect material is buried well below the surface to prevent contamination spread If there is a risk of contaminated material contacting uncontaminated ground, employing clean backfill material for part of the excavation is recommended To prevent surface contamination after the investigation, measures such as importing clean material to create a protective surface layer or disposing of excavated material off-site should be considered, ensuring environmental safety throughout the process.
Local regulations and national legislation shall be observed
When backfilling contaminated boreholes, it is essential to grout the borehole to prevent the spread of contaminants Proper disposal of borehole arisings off-site to a suitable location further ensures environmental safety These precautions help contain contamination and protect groundwater sources effectively.
Any surplus excavated material should be collected for safe disposal
General
Choosing the appropriate sampling technique depends on several key questions, including identifying the soil characteristics of interest, determining the required sample type, and assessing the necessary sample volume for planned investigations It is essential to consider the desired precision of results to select a suitable method, while also evaluating the accessibility of the sampling site and the required sampling depth Additionally, understanding the basic physical soil characteristics is crucial to ensure accurate and reliable analysis, making these considerations vital for effective soil sampling and analysis in geotechnical and environmental studies.
The selection of the most suitable sampling technique depends on several key factors, including costs, safety considerations, the availability of qualified staff, necessary machinery or instruments, time constraints, and environmental impacts It is essential to thoroughly evaluate these aspects to ensure an effective and reliable sampling process Additionally, the rationale behind the final choice should be well-documented to provide transparency and support future reference Proper documentation of the decision-making process enhances the credibility and reproducibility of the sampling strategy.
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Collecting samples for physical, geological, and biological analyses requires specialized tools and techniques to ensure accuracy and integrity It is essential that sampling procedures are performed under the supervision of qualified experts to ensure reliability and compliance with scientific standards Proper sampling methodology enhances data quality and supports effective research and decision-making.
Sampling methods can be performed using either machinery or manual techniques, depending on the specific requirements Samples may be collected from near the ground surface, at varying depths below ground level, or from deep beneath the surface to assess subsurface conditions Achieving the desired sampling depth can be accomplished through excavations such as trial pits, driven probes, or drilling methods like boreholes, ensuring accurate and representative data collection for geotechnical analysis.
Table 1 offers guidance on selecting suitable sampling techniques based on expected site investigation conditions While it provides valuable direction, not all possible scenarios can be covered, requiring professional judgment to determine the most appropriate sampling method for each unique situation.
Annex A outlines the most commonly used methods for sampling and accessing sampling points, ensuring standardized procedures While these methods are standard, alternative techniques suitable for specific locations, such as permafrost areas, are permitted It is essential to follow the core principles of sample collection and adopt an appropriate sampling approach to obtain representative and reliable samples, regardless of the method used.
The selection of an appropriate sampling method depends on various factors such as the distribution of sampling locations, the size and type of samples, and the characteristics of the site It is essential to consider any challenges posed by the site that may affect the investigation process This ensures the sampling strategy aligns with the specific needs of the study, leading to accurate and reliable results.
Sampling during borehole construction is essential for ensuring the integrity needed for comprehensive chemical, physical, and biological analysis of targeted soil horizons Gas and water sampling are also conducted for rapid data collection, such as monitoring methane, carbon dioxide, and volatile organic compounds in the borehole Regular monitoring of groundwater horizons for hydrogeological and chemical parameters is recommended, ideally using cased wells or standpipes installed in boreholes The sampling strategy should be designed to meet specific monitoring objectives, guiding borehole construction to ensure proper well design and accurate data collection.
Table 1 — Applicability of ground excavation, drilling and sampling techniques
Suitability for ground type Designa- tion Method Method of sample extraction
Soil profile detail mm Unsuitable for soil type Suitable for soil type
Hand auger Rotary With auger 50 mm to
100 mm 50 Non- cohesive gravel, stones, rubble, lumps of material
Clay, silt, cohesive sand and similar ground
No Disturbed 0 to 2,0 Sampling to
5,0 m possible in cohesive sandy ground
Hand excavation Digging With sampling tool 1 m ¥ 1 m 10 Solid concrete or similar obstruction
All types No Disturbed or undisturbed 0 to 1,5 In unstable ground the sides may need support
Power auger Rotary With auger 50 mm 50 Non- cohesive gravel, large stones, lumps of material
Clay, silt, cohesive and similar ground
5,0 m possible in cohesive sandy ground
Ramming With sample tool on machine
50 mm 25 Gravels, large stones, lumps of material
Clay, silt, cohesive sand and similar ground
Various bits > 30 mm 150 to 2 500 No natural obstructions
All types including glacial till and bedrock
0 to 100 Suitable specially in glaciated terrain
Light cable Percussion With boring tools 150 mm to
250 mm 100 Obstructions, e.g tyres, wood, concrete
Clay, silt, cohesive sand and similar ground
(Open hole) Rotary Not possible
500 mm 300 to 500 Solid obstructions All soils No None 1,0 to 40 Suitable for passing through top layers which are not of interest
(Core drill) Rotary Retrieval of core 150 mm to
500 mm 300 to 500 Solid obstructions All soils No None 1,0 to 20
Continuous flight auger Rotary Not possible 150 mm to
500 mm 300 to 500 Solid obstructions All soils No None 1,0 to 20 Suitable for passing through top layers which are of interest
Hollow stem auger Rotary With sampling equipment down stem
500 mm 50 Solid obstructions All soils Yes Disturbed and undisturbed
1,0 to 20 Sampling down centre stem with auger in situ
Driven probes Pressure Retrieval of core 30 mm to
150 mm 10 Solid obstructions All soils Yes Disturbed and undisturbed
0 to 30 Core obtained and in situ instruments possible in some cases
Trial pit Digging With sampling tools
1 m 10 Large solid obstructions All soils and material No Disturbed and undisturbed
Cross-contamination
Ensuring sample integrity is crucial, regardless of the sampling method used It is essential that the sampling system and equipment materials do not contaminate the sample, preventing contamination from contact with sampling devices or containers Additionally, measures should be taken to avoid the loss of contaminants through adsorption or volatilization, maintaining the sample's accuracy and reliability for analysis.
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To prevent cross-contamination, it is essential to keep sampling equipment clean between samples For agricultural sampling, the device must be thoroughly cleaned after each location when creating composite samples across a field Similarly, in geological and contamination investigations, all sampling equipment should be meticulously cleaned between each sample to ensure accurate results and prevent residue transfer.
Contamination of samples due to lubrication used to ease sample collection, or contamination due to lubricants and oils, greases or fuels due to the machinery used for sampling, should be avoided If it is necessary to use lubrication, e.g water, to ease formation of a borehole to enable sample collection, only lubrication should be used which will not conflict with nor confound the analysis to be performed on the samples in the sense of matrix effects or contribution to the contamination
For accurate sample placement, always use a stainless steel hand trowel It is essential to verify the quality of the stainless steel beforehand to prevent cross-contamination, ensuring the integrity and reliability of analytical data.
Common drilling, excavation, and sampling methods typically yield disturbed ground samples For projects requiring undisturbed samples, specialized sampling equipment and meticulous techniques are essential to ensure sample integrity, highlighting the importance of proper collection methods in geotechnical investigations.
Undisturbed samples
For undisturbed soil samples, use tools like a sampling frame, coring device, or cylinder to ensure the soil maintains its original physical structure These sampling devices are inserted into the soil and carefully extracted with the sample, preserving the soil's natural condition for accurate analysis.
General
Sampling and preservation methods vary significantly for physical, chemical, and biological (including microbiological) analyses Proper storage, transportation speed, and technique must align with the investigation's objectives and required accuracy Consulting the laboratory beforehand is essential to ensure appropriate procedures are followed for reliable results.
For optimal sample integrity, it is essential to keep samples chilled below 5 °C, especially during transport to the laboratory, starting from the moment of collection Using recreational coolers for transportation may not ensure the controlled temperature conditions necessary to preserve sample quality.
NOTE See also ISO 10381-1 and ISO 10381-5.
Sample containers
For sampling uncontaminated soils, containers made of polyethylene (such as buckets, wide-mouth bottles and strong bags) may be used, as they are inert, relatively cheap and convenient
When sampling areas suspected of contamination, it is crucial to use sample containers made of materials that preserve the sample's representativeness The container must not transfer contamination or absorb components of the sample, such as pesticides or oils Plastics containers, for example, may not be suitable for organic contaminants Additionally, polyethylene bags are generally not recommended for contaminated soils, with certain exceptions outlined in specific guidelines.
Ensure the container is securely sealed to prevent the loss of volatile components like moisture or solvents during sample collection and transportation Proper sealing also avoids the separation of components, maintaining sample integrity for accurate laboratory analysis.
Specialized containers are essential for sampling organic compounds like solvents to ensure sample integrity Screw-capped bottles and jars with secure closures effectively prevent contamination and loss of volatiles during storage and transport Using appropriate sampling containers helps maintain sample purity and complies with safety and quality standards.
Addition of a non-aqueous solvent/liquid, e.g methanol, may be required to minimize loss of volatile organic compounds
Proper sample containers must always be filled and sealed to minimize free air space, ensuring sample integrity When using plastic bags, they should be sealed airtight by welding the open end; however, the weld is a potential weak point that can easily tear, jeopardizing the sample's safety.
Table 2 — Suitability of sample containers
Container material Acid Alkaline Oils and tars Solvents Gas Inorgaic Oils and tars
Solvents and organic com- pounds
Plastic bag ++ ++ – – + + a – – – Low cost Removing excess air Easily damaged
Cost Aluminium contamination Affected by acids/alkali
Tins with push- fit lids – – ++ ++ – ++ ++ + + –
Rusting Affected by acids ++ Very suitable
It is recommended to consult the analyzing laboratory to select the appropriate sample container, ensuring optimal sample integrity These containers should not be used for contaminated land or investigation samples if analysis for organic contamination is necessary For best results when volatile organic compounds are present, using undisturbed samples with solvents like methanol may be required Additionally, employing PTFE septums can be appropriate to prevent sample contamination and maintain sample quality.
8.2.2 Sample containers for agricultural purposes
When collecting composite samples for agricultural analysis, use a sufficiently large container, such as a new polyethylene bag or a reusable polyethylene or polypropylene bucket, to hold all sample portions Ensure bags are new, and re-use buckets only after thorough cleaning to prevent contamination After sampling, transfer the sample into a secure container or tightly tie the sample bag to minimize air exposure during transport Protect polyethylene bags from physical damage to prevent sample loss or contamination, ensuring sample integrity for accurate laboratory analysis.
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8.2.3 Sample containers for contaminated land
For standard sample collection, plastic buckets with fitted lids or sturdy plastic bags are commonly used, ensuring sample integrity and ease of handling Recommended containers include polyethylene or polypropylene buckets capable of holding approximately 2 kg of material, ideal for most routine analyses When larger samples are needed, heavy-duty polyethylene bags offer a convenient alternative, provided there is no chemical interaction or volatility concerns that could lead to sample loss To prevent contamination or physical damage, double-bagging is advised, safeguarding sample quality during transport and storage.
Ensure the container is filled and sealed tightly to minimize air space, preserving sample integrity It is crucial to select containers that neither transfer contamination to the sample nor absorb its components, maintaining sample purity and accuracy.
When analyzing organic compounds, it is essential to use inert containers such as wide-mouthed glass bottles, screw-capped aluminum containers, or tins with press-on lids to prevent the loss of volatile materials These containers should be well-sealed to avoid absorption or evaporation of the sample, ensuring accurate and reliable results by preventing contamination and material loss.
Vapour-seal caps should be used where head-space analysis is to be carried out Special sample bottles are available for dynamic head-space analysis
Addition of a non-aqueous solvent/liquid, e.g methanol, may be required to minimize loss of volatile organic compounds
Having a variety of sample containers readily available on-site is essential to ensure proper sampling of all potential materials based on contamination hypotheses, as suggested by ISO 10381-1 This preparedness helps facilitate accurate assessment and analysis of different substances, ensuring comprehensive and reliable results.
8.2.4 Sample containers for geological purposes
Sample containers for geological and contaminated land analysis are often similar, with plastic bags being an acceptable option in many cases Additionally, strong paper bags and cotton sacks can be effectively used as sample containers, providing versatile and practical solutions for sample collection.
Labelling
Proper labeling of samples is essential once a sample is obtained, ensuring it is clearly and uniquely identified Labels should include details as specified in ISO 10381-1 to maintain consistency and traceability Suitable labeling methods include tie-on labels, adhesive labels with secure adhesion under on-site conditions, writing directly on the sample container, or placing a protected label inside the container to prevent damage from the contents Accurate and durable labeling is crucial for maintaining sample integrity throughout handling and analysis.
Choose durable labels that withstand external elements such as rain and contamination, ensuring they remain intact during future treatments like abrasion, handling, and chemical exposure Ensure the labels are sufficiently large to clearly display all necessary information in a legible manner, enhancing safety and compliance.
Sample storage
Cooling and storing soil samples below 5 °C is essential to prevent sample deterioration and maintain integrity Using portable cold boxes on-site ensures effective temperature control and facilitates safe transportation to the laboratory Proper cooling techniques help preserve sample quality for accurate analysis.
NOTE Recreational cold boxes may not provide adequately controlled conditions
Care shall be taken, especially in hot and humid climates, if cooling causes condensation of soil gas moisture that might leach the sample
To prevent degradation of organic compounds such as hydrolysis, oxidation, enzymatic, and microbial breakdown, samples should be stored at temperatures below −25 °C, especially during transportation, as temperatures just below 5 °C are insufficient to suppress these processes and may adversely affect sample integrity.
Achieving temperatures as low as −25 °C is possible through the use of dry ice (solid carbon dioxide) packing, liquid nitrogen containers, or freezer boxes powered by car batteries These methods ensure effective temperature control for sensitive items, complying with ISO 2002 standards Proper insulation and handling are essential to maintain the desired low temperatures during transportation and storage Utilizing appropriate cooling solutions enhances product safety and quality, aligning with industry best practices and SEO considerations for cold chain management.
Proper handling of undisturbed soil samples is crucial to maintain their original structure Follow recommended cooling and storage protocols, and handle samples carefully during transport to prevent disturbance, ensuring accurate laboratory analysis and reliable test results.
A comprehensive sampling report must include details on sampling location, personnel involved, observations, and sample identification It should also provide a clear description of the sampling method and devices used Any deviations from the original sampling procedure, along with the reasons for such changes, must be documented to ensure transparency and accuracy.
NOTE See also ISO 10381-1, ISO 10381-4 and ISO 10381-5
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Manually and power-operated sampling tools
Various hand-auger sampler designs have been developed over the years to accommodate different soil types and conditions, enhancing their effectiveness Ease of use depends on the ground's nature, with handheld augers being more user-friendly in sandy soils, especially where obstructions like stones are present In sandy soils, hand augers can typically reach depths of approximately 5 meters, making them suitable for sampling homogeneous soils such as agricultural lands.
When using hand augers for soil sampling, it is essential to prevent contamination by ensuring that no materials from higher up the bore enter the sample during augering or withdrawal Carefully lining the borehole with a plastic tube helps to avoid cross-contamination and maintains the integrity of the soil sample Proper technique and equipment are crucial for accurate and reliable soil analysis.
Preferred hand augers for soil sampling are those designed to extract core samples, ensuring accurate collection of soil data While other auger types may be employed to drill to the required depth, it is essential that the bore is thoroughly cleaned afterward to prevent cross-contamination, maintaining sample integrity.
Hand auger sampling enables detailed observation of the ground profile and precise collection of samples at specific depths Ensuring that samples are representative is essential, especially when investigating localized contamination zones Proper sampling techniques help achieve accurate environmental assessments and reliable data for analysis.
When using a hand auger for soil sampling in agricultural testing, it is crucial that the auger reliably collects consistent sample volumes, especially when creating composite samples Typically, soil samples are taken from the near-surface layer at depths ranging from 150 mm to 250 mm Ensuring uniform sampling depth and volume enhances the accuracy and reliability of soil test results, supporting better agricultural decision-making.
It is possible to obtain augers powered by small motors to reduce the labour required to carry out the sampling
To prevent cross-contamination within the bore, it is essential to follow proper procedures, whether using power-operated or hand augers (see 7.2 and A.1.1) Power augers mounted on rough-terrain vehicles are commonly used for repetitive sampling in agricultural applications, highlighting the importance of maintaining cleanliness to ensure accurate and uncontaminated results.
When utilizing fuel-powered motors for sampling, caution is essential to prevent contamination from fuel, motor lubrication, and exhaust fumes To mitigate these risks, electric-powered augers are available and recommended, offering a cleaner and safer alternative for sediment and soil sampling.
Light-cable percussion boring is commonly used with a mobile rig equipped with a 1 to 2-ton capacity winch powered by a diesel engine The setup includes a tripod derrick approximately 6 meters tall, designed for stability and efficiency Many models feature foldable derricks, allowing the rig to be easily towed by small vehicles, such as 4-wheel drive trucks, for versatile and convenient operation.
The light-cable percussion technique is commonly used for geotechnical purposes, and deep boreholes of over
20 m depth can be constructed This technique can be of particular use in investigating deep sites such as refuse tips and other unstable ground
Ground penetration methods vary depending on soil type, with clay cutters used for cohesive soils and shell or bailer tools for cohesionless soils Hard ground and obstructions are penetrated using chisels The borehole is supported with a steel casing that advances as drilling progresses, preventing cross-contamination It is essential to clean the borehole after each casing advancement to ensure accurate sampling.
The type of ground significantly influences the drilling process; in clay strata, the tool can create a borehole before the steel casing is inserted As the casing is pushed down the borehole, material from the sides may become dislodged, leading to potential cross-contamination Proper understanding of soil conditions and drilling techniques is essential to minimize contamination risks during steel casing installation.