ISO 5667-18:2001
(Main)Water quality — Sampling — Part 18: Guidance on sampling of groundwater at contaminated sites
Water quality — Sampling — Part 18: Guidance on sampling of groundwater at contaminated sites
Qualité de l'eau — Échantillonnage — Partie 18: Lignes directrices pour l'échantillonnage des eaux souterraines sur des sites contaminés
Kakovost vode - 18. del: Navodilo za vzorčenje podzemne vode na onesnaženih mestih
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 5667-18
First edition
2001-04-15
Water quality — Sampling —
Part 18:
Guidance on sampling of groundwater at
contaminated sites
Qualité de l'eau — Échantillonnage —
Partie 18: Lignes directrices pour l'échantillonnage des eaux souterraines
sur des sites contaminés
Reference number
ISO 5667-18:2001(E)
©
ISO 2001
---------------------- Page: 1 ----------------------
ISO 5667-18:2001(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.
© ISO 2001
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.ch
Web www.iso.ch
Printed in Switzerland
ii © ISO 2001 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 5667-18:2001(E)
Contents Page
Foreword.iv
Introduction.vi
1 Scope .1
2 Terms and definitions .1
3 Sampling strategy and programme design.3
3.1 General.3
3.2 Selection of sampling point location.3
3.3 Groundwater parameter selection .5
3.4 Sampling frequency.5
4 Types of monitoring installation .6
4.1 General.6
4.2 Unsaturated zone monitoring.6
4.3 Saturated zone .9
4.4 Construction materials for sampling installations.14
5 Sampling procedures .15
5.1 Well cleaning and development .15
5.2 Purging .16
5.3 Trial pits.19
5.4 Sampling of free-phase contaminants (DNAPLs and LNAPLs) .19
5.5 Materials for sampling equipment .19
5.6 Prevention of contamination .20
5.7 Preservation, stabilization and transport of samples.20
6 Safety precautions.21
7 Sample identification and records.21
8 Quality assurance/quality control.21
Annex A (normative) Calculation of sampling frequency using a nomogram.22
Bibliography.23
© ISO 2001 – All rights reserved iii
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ISO 5667-18:2001(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 3.
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 part of ISO 5667 may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 5667-18 was prepared by Technical Committee ISO/TC 147, Water quality,
Subcommittee SC 6, Sampling (general methods).
ISO 5667 consists of the following parts, under the general title Water quality — Sampling:
— Part 1: Guidance on the design of sampling programmes
— Part 2: Guidance on sampling techniques
— Part 3: Guidance on the preservation and handling of samples
— Part 4: Guidance on sampling from lakes, natural and man-made
— Part 5: Guidance on sampling of drinking water and water used for food and beverage processing
— Part 6: Guidance on sampling of rivers and streams
— Part 7: Guidance on sampling of water and streams in boiler plants
— Part 8: Guidance on sampling of wet deposition
— Part 9: Guidance on sampling from marine waters
— Part 10: Guidance on sampling of waste waters
— Part 11: Guidance on sampling of groundwaters
— Part 12: Guidance on sampling of bottom sediments
— Part 13: Guidance on sampling of sludges from sewage and water-treatment works
— Part 14: Guidance on quality assurance of environmental water sampling and handling
— Part 15: Guidance on preservation and handling of sludge and sediment samples
— Part 16: Guidance on biotesting of samples
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ISO 5667-18:2001(E)
— Part 17: Guidance on sampling of suspended sediments
— Part 18: Guidance on sampling of groundwater at contaminated sites
— Part 19: Guidance on sampling of sediments in the marine environment
Annex A forms a normative part of this part of ISO 5667.
© ISO 2001 – All rights reserved v
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ISO 5667-18:2001(E)
Introduction
The guidance in this part of ISO 5667 can be used in parallel with other guidance on investigating contaminated or
potentially contaminated sites as any groundwater sampling from such sites is likely to form part of a much wider
investigation programme.
Groundwater sampling, in general, is carried out to determine whether or not the groundwater in or beneath a site
is contaminated. It can also be used to satisfy the following additional objectives:
� to establish whether any migration of contaminants, derived from the site, is occurring and characterize the
spatial extent of any contamination and its form;
� to determine the direction and rate of groundwater flow and contaminant migration;
� to provide data for undertaking a risk assessment;
� to provide an early warning system for the impact of contaminants on the quality of groundwater resources,
surface waters and other potential receptors in the vicinity of the site;
� to monitor the performance and effectiveness of remedial measures or facility design.
� to demonstrate compliance with licence conditions, or collect evidence for regulatory purposes.
� to assist in the selection of remedial measures and remediation process design.
This guidance includes sampling of groundwater from both the saturated (below water table) zone and the
unsaturated (above the water table) zone.
Development of a groundwater sampling programme depends on the purposes of the investigation. This part of
ISO 5667 provides guidance to inform the user of the necessary considerations when planning and undertaking
groundwater sampling from potentially contaminated sites. Examples of typical sites include:
� present or former industrial sites with a history of potentially contaminatory activities;
� waste disposal (landfill) sites;
� sites where natural and/or artificial processes have led to potential land and groundwater contamination;
� sites where products have been spilled e.g. as a result of transportation accidents.
The guidance contained in this part of ISO 5667 covers selection of sampling points, the selection of sampling
installations and devices, groundwater parameter selection and sampling frequency.
Prescriptive guidance on methods and applications is not possible. Therefore, this guidance provides information
on the most commonly applied, and available, techniques and lists their advantages, disadvantages and limitations
of use where these are known. When considering design of sampling strategies, the properties of the contaminant
source, pathways for migration and the receptors need to be considered.
vi © ISO 2001 – All rights reserved
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INTERNATIONAL STANDARD ISO 5667-18:2001(E)
Water quality — Sampling —
Part 18:
Guidance on sampling of groundwater at contaminated sites
1 Scope
This part of ISO 5667 provides guidance on the sampling of groundwater at potentially contaminated sites. It is
applicable to situations where contamination of the subsurface could exist as a result of downward migration of
pollutants whose source is at the surface or just below it, and when the guidance provided in ISO 5667-11 is
inappropriate.
2 Terms and definitions
For the purposes of this part of ISO 5667, the following terms and definitions apply.
2.1
piezometer
device consisting of a tube or pipe with a porous element or perforated section (surrounded by a filter) on the lower
part (piezometer tip), that is installed and sealed into the ground at an appropriate level within the saturated zone
for the purposes of water level measurement, hydraulic pressure measurement and/or groundwater sampling
2.2
nested piezometers
group of piezometers installed within a single larger-diameter borehole
NOTE In general, each piezometer should be designed to allow sampling over a specific depth interval within the aquifer.
Piezometer tips are isolated from each other by installing a permanent impermeable seal between them.
2.3
multiple boreholes
group of individual boreholes or piezometers installed separately to form a monitoring network adequate for the
purposes of an investigation
2.4
multi-level sampler
single installation for sampling groundwater from discrete depths within the sub-surface
NOTE The device can be driven directly into the ground, installed in a pre-existing borehole or installed in a purpose-drilled
hole. When installed in a borehole, integral packers are used to isolate individual sample ports.
2.5
aquifer
geological formation (bed or stratum) of permeable rock or unconsolidated material (e.g. sand and gravels) capable
of yielding significant quantities of water
2.6
aquitard
geologic stratum of formation of low permeability that impedes the flow of water between two aquifers
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ISO 5667-18:2001(E)
2.7
saturated zone
part of an aquifer in which the pore spaces of the formation are completely water-saturated
2.8
unsaturated zone
part of an aquifer in which the pore spaces of the formation are not totally water-saturated
2.9
groundwater
water in the saturated zone and/or unsaturated zone of an underground geological formation or artificial deposit
such as made ground
2.10
perched water table
isolated body of groundwater, which is limited in lateral and vertical extent, located within the unsaturated zone
overlying a much more extensive groundwater body
2.11
matrix potential
combination of forces, independent of gravity, acting on soil water (water contained within the pores of a soil/rock
matrix) that exist as a result of the attraction of solid surfaces to water and the attraction of water molecules to each
other
NOTE Generally, the smaller the particle size, the higher the matrix potential.
2.12
check valve
mechanical valve which allows fluids to pass in only one direction
NOTE The pressure of fluids flowing through the valve in one direction has the effect of opening the valve and in the other
of closing it.
2.13
receptor
entity that is vulnerable to the adverse effect(s) of a hazardous substance or agent
EXAMPLES Human, animal, water, vegetation, building services, etc.
2.14
packer
device or material for temporarily isolating specified vertical sections within boreholes in which to perform
groundwater sampling from discrete zones or locations within the borehole or aquifer
2.15
hydraulic conductivity
property of a water-bearing formation that relates to its capacity to transmit water through its internal,
interconnected pathways
2.16
effective porosity
proportion of saturated openings or pores within a water-bearing formation which contribute directly to the flow of
groundwater
NOTE Effective porosity is represented as the ratio of this volume of pore space to the total volume of rock.
2.17
field capacity
maximum amount of water that a soil or rock can retain after gravitational water has drained away
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ISO 5667-18:2001(E)
2.18
dense non-aqueous phase liquids
DNAPL
organic compounds that have a low water solubility and a density greater than that of water
EXAMPLES Chlorinated hydrocarbons such as trichloroethane.
2.19
light non-aqueous phase liquid
LNAPL
organic compounds that have a low water solubility and a density less than that of water
EXAMPLE Petroleum products.
3 Sampling strategy and programme design
3.1 General
Groundwater sampling can be carried out as a single exercise or as part of a larger site or environmental
investigation. Regardless of the purpose, a rational approach should be taken that clearly defines the objectives,
determines the level of information needed and identifies the various stages of the investigation.
It should be noted that, normally, groundwater sampling from the saturated zone alone cannot fully assess the level
of contamination of a site in situations where an unsaturated zone of considerable thickness exists. The potential
consequence of ignoring the unsaturated zone is that the unsaturated zone and groundwater system could become
extensively contaminated before any tangible evidence of leakage or contamination is evident in samples collected
from below the water table.
3.2 Selection of sampling point location
The location of monitoring installations and the design of the network for sampling groundwater from (potentially)
contaminated sites should take account of the following:
� the hydrogeological setting of the investigation site;
� the past and future use(s) of the site;
� the purpose of the exercise;
� the likely contaminants;
� the extent of contamination.
All of these factors should be considered during the preliminary stages of the site investigation programme to
enable the most appropriate and effective sampling programme to be designed. This information can be obtained
by examining all available information held by site owners (or their agents), local, regional and national regulatory
agencies and other data holders. Table 1 provides an overview of the steps involved in planning an investigation
strategy and for sampling groundwater from sites that are potentially contaminated.
In addition to the scientific requirements, other factors can influence the location of sampling points. These include
practical, environmental and safety considerations such as the ground slope, proximity of underground services
(gas pipes, electricity cables etc) and overhead clearance for drilling rigs and other sampling devices.
To establish whether migration of contaminants is occurring and determining the direction and rate of this
migration, monitoring points should be located inside and outside the contaminated area and both up and down the
hydraulic gradient. A greater number of sample points should be positioned down gradient, both inside and outside
of any contaminant plume.
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ISO 5667-18:2001(E)
Where site analysis indicates that the site is underlain by complex geology or that contaminants with a broad range
of physical and chemical properties are likely to be present, an increased number of monitoring points should be
installed for adequate characterization of the contaminant distribution. In addition to investigating the lateral
variation caused by heterogeneity, the sampling strategy should also be designed to investigate any vertical
variations.
[9]
Table 1 — Procedural steps for sampling groundwater (adapted from )
Step
(with reference to other ISO Procedure Essential elements Notes
standards)
Investigation/monitoring Collation of available data Identify data sources Geological, geochemical and
strategy (ISO 5667-1) hydrogeological characterization
Desk study
Develop conceptual model
See 3.2, 3.3 and 3.4
Design borehole/sampling point
Reconnaissance survey
network and sampling programme
Facility installation Installation of monitoring points Borehole design, material Seeclause4
by drilling selection and installation technique
See 5.1
Well cleaning and development
Well inspection Hydrologic measurements Water level measurements Hydrogeological characterization
Hydraulic testing
Well purging Removal or isolation of stagnant Representative groundwater See 5.1
water
Verification of representative See 5.2
Determination of well-purging
groundwater
parameters (e.g. EC, pH,
temperature, redox potential)
Sample collection Sample collection by appropriate See 4.2 and 4.3
Filtration mechanism
Field determinations
Unfiltered Field filtered Field determination of sensitive
(ISO 5667-2, ISO 5667-11,
sample sample parameters, pH, electrical
ISO 5667-3)
conductivity, temperature, redox
potential, dissolved oxygen as
appropriate
Organics (all) Alkalinity/pH Head-space free samples See 5.4, 5.5 and 5.6
Dissolved gases Dissolved trace Minimal aeration or de-
metals for pressurization
specific
geochemical
information
Sensitive Sulfide and other Minimal air contact Blanks and spiked samples
inorganic sensitive should be prepared in accordance
species, e.g. inorganics with ISO 5667-14
nitrite,
ammonium,
iron(II)
Tracer metals for Major cations Sample preservation
mobile (colloidal) and
loads anions
Storage and transport of Minimal loss of sample integrity See 5.7, clauses 6, 7 and 8
samples (ISO 5667-3) prior to analysis
Care should be taken when identifying the prevailing flow regime as localized recharge to the subsurface can alter
the regional hydraulic gradient. This can result in groundwater flow and contaminant transportation in a direction
that is contrary to flow imposed by the regional gradient. Dense non-aqueous phase liquids (DNAPLs) can also
move in a different direction and at a different rate to that of groundwater because their chemical properties are
4 © ISO 2001 – All rights reserved
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ISO 5667-18:2001(E)
different to those of water. Their migration is also affected by the geological structure of the low permeability layer
underlying the saturated aquifer.
Light non-aqueous phase liquids (LNAPLs) also have different chemical properties to those of water and their
migration and distribution will be affected by the geological structure and chemical interactions within the
unsaturated zone and zone of water table fluctuation.
Where sampling is aimed at providing an early warning of the impact of contaminants on receptors, monitoring
points should be located between the contaminant source (and plume) and the potential receptors as well as within
the zone of contamination, e.g. at landfill sites, monitoring points should be established around the outside of, but
close to, the landfill.
Sample points within the zone of contamination and outside (both up and down the hydraulic gradient) should be
installed to measure performance and effectiveness of remediation and for demonstrating compliance to licence
conditions.
3.3 Groundwater parameter selection
The parameters selected for analysis should reflect the nature of the investigation and/or the former, current and
proposed future use of the site. In some cases, certain contaminants will be the subject of national regulations.
Focussing only on these, however, could be inadequate for providing the complete picture of contamination under
different geochemical and hydrogeological conditions. For example, where organic contaminants are susceptible to
degradation, the list of analytes should also include the degradation products, which in some cases can also be
hazardous. An example of this is the degradation of trichloroethylene (TCE), a DNAPL. One of its potential
degradation products is vinyl chloride, a relatively soluble and highly volatile compound.
Consideration should also be given to baseline or natural groundwater concentrations. Elevated concentrations can
already be present in the environment being investigated as a result of natural sources of contamination.
3.4 Sampling frequency
The frequency of sampling depends on the objectives of the investigation. If the investigation is designed to map an
established contaminant plume, a single-event sampling exercise may be used. In this case, sampling should be
completed as rapidly as possible to minimize the effects of temporal variation. Where the development of a plume
is to be monitored and/or the impacts on groundwater resources considered, the frequency should be based on the
prevailing hydrogeological and environmental conditions, the objectives of the study and the contaminants present.
Where monitoring is required to provide early warning, where there are compliance issues or for performance
assessment of remedial measures, in general, a recommended minimum sampling frequency is quarterly for most
chemical constituents (e.g. major ions, etc.) and monthly for those that are more mobile and reactive (e.g. VOCs
and dissolved gases).
However, where environmental conditions indicate that changes can occur more rapidly, more frequent sampling
should be carried out. In these cases, the exact frequency should be determined by examination of all influencing
natural and artificial factors. Examples of short-term influencing factors include tidal influences and localized rainfall
as well as ground disturbance caused by ground engineering activities.
One example of how sampling frequency can be determined using prevailing hydrogeological properties (including
hydraulic gradient, hydraulic conductivity and effective porosity) is shown in Figure 1. Relevant hydrogeological
[8]
parameters have been used to develop a nomogram, which has been adapted from to include the effects of
dispersion, for rapid estimation of sampling frequency. Dispersion has the effect of distributing the contaminant
both along the flow path and perpendicular to it. The modification applied leads to a 10 % increase in sample
frequency. A worked example is described in annex A.
Other environmental conditions can also influence the temporal distribution and concentration of contaminants in
groundwater and soil water and these should be considered during development of the sampling strategy.
Seasonal and more frequent variations in weather and climate can influence the rate of infiltration of contaminants
through the unsaturated zone. A rise in water table can also lead to the release (or re-release) of contaminants into
the groundwater and/or bring the contaminant source closer to the groundwater.
© ISO 2001 – All rights reserved 5
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ISO 5667-18:2001(E)
����
DN DN
F�� 0,1
����
��86 400Ki ��86 400Ki
[8]
Figure 1 — Nomogram for estimating sampling frequency (from )
4 Types of monitoring installation
4.1 General
Installations suitable for groundwater monitoring typically involve placement of access tubes for portable sampling
devices or burial of sensors or samplers in situ. These installations may be positioned within the saturated zone
(below the water table) or above it (unsaturated zone). In addition to sampling groundwater, installations below the
water table can be used to measure water levels and installations above the water table can measure soil gas and
soil moisture content.
4.2 Unsaturated zone monitoring
4.2.1 Introduction
Sampling techniques that are used for collection of groundwater from the unsaturated zone can be divided into two
types:
� solid sampling followed by extraction of groundwater (pore fluids);
� unsaturated pore fluid sampling.
4.2.2 Extraction from solid samples
4.2.2.1 General
The extraction of pore fluids from solid samples is the most widely used method for sampling groundwater in the
unsaturated zone. Collection of solid samples as part of this method can also allow useful geological information to
be obtained. There are two broad categories of solid sampling methods: hand-operated and power-operated.
Table 2 lists a range of suitable techniques that can be used for extracting solid samples for pore fluid collection.
6 © ISO 2001 – All rights reserved
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ISO 5667-18:2001(E)
The removal of solid samples from the ground is however a destructive form of sampling that, although necessary,
does not allow subsequent re-sampling from the same location. It therefore precludes taking samples at a later
date for analysis of trends.
Table 2 — A range of methods suitable for soil and rock sampling
Drilling
Method Soil/rock type Maximum depth Diameter range
a
fluid/flush
Trial pitting
Hand- All soil types and Maximum6m(but no Depends on depth of
powered unconsolidated rocks generally to 4 m) pit and soil/rock type
Tube Hand- Soils, clay and fine grained
sampling
powered unconsolidated geological Approximately 10 m no 25 mm to 75 mm
materials
Hand- Soils, clay and unconsolidated Approximately 5 m no 50 mm to 100 mm
Auger powered (e.g. geological materials
Approximately 30 m no 75 mm to 300 mm
“hollow stem”)
Cable tool
Soils, clay and unconsolidated no/yes
80 mto90m 150 mm to 300 mm
(e.g. “shell and auger”
geological materials water
drilling or “light
percussion” drilling)
Rotary yes
All types of geological
air, water,
>100 m 100 mm to 200 mm
(e.g. “direct” and “reverse
materials and made ground
mud, foam
rotary”)
etc.
a
Drilling fluids are required to lift drill cuttings, support the borehole whilst drilling, lubricate and cool the drill bit. Use of techniques where
drilling fluids are required may adversely affect sample quality.
4.2.2.2 Hand-operated samplers
These are typically tube-type or auger samplers. The tube samplers consist of a variable-length rod with hollow
sample chamber (of variable length and diameter). It is hammered into the ground to obtain a sample. Augers have
cutting bits at their lower end and a sample chamber (open at top and bottom) directly above. The sampler is
rotated into the ground by hand.
4.2.2.3 Power-operated sampling r
...
SLOVENSKI STANDARD
SIST ISO 5667-18:2001
01-december-2001
.DNRYRVWYRGHGHO 1DYRGLOR]DY]RUþHQMHSRG]HPQHYRGHQDRQHVQDåHQLK
PHVWLK
Water quality -- Sampling -- Part 18: Guidance on sampling of groundwater at
contaminated sites
Qualité de l'eau -- Échantillonnage -- Partie 18: Lignes directrices pour l'échantillonnage
des eaux souterraines sur des sites contaminés
Ta slovenski standard je istoveten z: ISO 5667-18:2001
ICS:
13.060.10 Voda iz naravnih virov Water of natural resources
13.060.45 Preiskava vode na splošno Examination of water in
general
SIST ISO 5667-18:2001 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST ISO 5667-18:2001
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SIST ISO 5667-18:2001
INTERNATIONAL ISO
STANDARD 5667-18
First edition
2001-04-15
Water quality — Sampling —
Part 18:
Guidance on sampling of groundwater at
contaminated sites
Qualité de l'eau — Échantillonnage —
Partie 18: Lignes directrices pour l'échantillonnage des eaux souterraines
sur des sites contaminés
Reference number
ISO 5667-18:2001(E)
©
ISO 2001
---------------------- Page: 3 ----------------------
SIST ISO 5667-18:2001
ISO 5667-18:2001(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.
© ISO 2001
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.ch
Web www.iso.ch
Printed in Switzerland
ii © ISO 2001 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 5667-18:2001
ISO 5667-18:2001(E)
Contents Page
Foreword.iv
Introduction.vi
1 Scope .1
2 Terms and definitions .1
3 Sampling strategy and programme design.3
3.1 General.3
3.2 Selection of sampling point location.3
3.3 Groundwater parameter selection .5
3.4 Sampling frequency.5
4 Types of monitoring installation .6
4.1 General.6
4.2 Unsaturated zone monitoring.6
4.3 Saturated zone .9
4.4 Construction materials for sampling installations.14
5 Sampling procedures .15
5.1 Well cleaning and development .15
5.2 Purging .16
5.3 Trial pits.19
5.4 Sampling of free-phase contaminants (DNAPLs and LNAPLs) .19
5.5 Materials for sampling equipment .19
5.6 Prevention of contamination .20
5.7 Preservation, stabilization and transport of samples.20
6 Safety precautions.21
7 Sample identification and records.21
8 Quality assurance/quality control.21
Annex A (normative) Calculation of sampling frequency using a nomogram.22
Bibliography.23
© ISO 2001 – All rights reserved iii
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SIST ISO 5667-18:2001
ISO 5667-18:2001(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 3.
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 part of ISO 5667 may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 5667-18 was prepared by Technical Committee ISO/TC 147, Water quality,
Subcommittee SC 6, Sampling (general methods).
ISO 5667 consists of the following parts, under the general title Water quality — Sampling:
— Part 1: Guidance on the design of sampling programmes
— Part 2: Guidance on sampling techniques
— Part 3: Guidance on the preservation and handling of samples
— Part 4: Guidance on sampling from lakes, natural and man-made
— Part 5: Guidance on sampling of drinking water and water used for food and beverage processing
— Part 6: Guidance on sampling of rivers and streams
— Part 7: Guidance on sampling of water and streams in boiler plants
— Part 8: Guidance on sampling of wet deposition
— Part 9: Guidance on sampling from marine waters
— Part 10: Guidance on sampling of waste waters
— Part 11: Guidance on sampling of groundwaters
— Part 12: Guidance on sampling of bottom sediments
— Part 13: Guidance on sampling of sludges from sewage and water-treatment works
— Part 14: Guidance on quality assurance of environmental water sampling and handling
— Part 15: Guidance on preservation and handling of sludge and sediment samples
— Part 16: Guidance on biotesting of samples
iv © ISO 2001 – All rights reserved
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SIST ISO 5667-18:2001
ISO 5667-18:2001(E)
— Part 17: Guidance on sampling of suspended sediments
— Part 18: Guidance on sampling of groundwater at contaminated sites
— Part 19: Guidance on sampling of sediments in the marine environment
Annex A forms a normative part of this part of ISO 5667.
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Introduction
The guidance in this part of ISO 5667 can be used in parallel with other guidance on investigating contaminated or
potentially contaminated sites as any groundwater sampling from such sites is likely to form part of a much wider
investigation programme.
Groundwater sampling, in general, is carried out to determine whether or not the groundwater in or beneath a site
is contaminated. It can also be used to satisfy the following additional objectives:
� to establish whether any migration of contaminants, derived from the site, is occurring and characterize the
spatial extent of any contamination and its form;
� to determine the direction and rate of groundwater flow and contaminant migration;
� to provide data for undertaking a risk assessment;
� to provide an early warning system for the impact of contaminants on the quality of groundwater resources,
surface waters and other potential receptors in the vicinity of the site;
� to monitor the performance and effectiveness of remedial measures or facility design.
� to demonstrate compliance with licence conditions, or collect evidence for regulatory purposes.
� to assist in the selection of remedial measures and remediation process design.
This guidance includes sampling of groundwater from both the saturated (below water table) zone and the
unsaturated (above the water table) zone.
Development of a groundwater sampling programme depends on the purposes of the investigation. This part of
ISO 5667 provides guidance to inform the user of the necessary considerations when planning and undertaking
groundwater sampling from potentially contaminated sites. Examples of typical sites include:
� present or former industrial sites with a history of potentially contaminatory activities;
� waste disposal (landfill) sites;
� sites where natural and/or artificial processes have led to potential land and groundwater contamination;
� sites where products have been spilled e.g. as a result of transportation accidents.
The guidance contained in this part of ISO 5667 covers selection of sampling points, the selection of sampling
installations and devices, groundwater parameter selection and sampling frequency.
Prescriptive guidance on methods and applications is not possible. Therefore, this guidance provides information
on the most commonly applied, and available, techniques and lists their advantages, disadvantages and limitations
of use where these are known. When considering design of sampling strategies, the properties of the contaminant
source, pathways for migration and the receptors need to be considered.
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SIST ISO 5667-18:2001
INTERNATIONAL STANDARD ISO 5667-18:2001(E)
Water quality — Sampling —
Part 18:
Guidance on sampling of groundwater at contaminated sites
1 Scope
This part of ISO 5667 provides guidance on the sampling of groundwater at potentially contaminated sites. It is
applicable to situations where contamination of the subsurface could exist as a result of downward migration of
pollutants whose source is at the surface or just below it, and when the guidance provided in ISO 5667-11 is
inappropriate.
2 Terms and definitions
For the purposes of this part of ISO 5667, the following terms and definitions apply.
2.1
piezometer
device consisting of a tube or pipe with a porous element or perforated section (surrounded by a filter) on the lower
part (piezometer tip), that is installed and sealed into the ground at an appropriate level within the saturated zone
for the purposes of water level measurement, hydraulic pressure measurement and/or groundwater sampling
2.2
nested piezometers
group of piezometers installed within a single larger-diameter borehole
NOTE In general, each piezometer should be designed to allow sampling over a specific depth interval within the aquifer.
Piezometer tips are isolated from each other by installing a permanent impermeable seal between them.
2.3
multiple boreholes
group of individual boreholes or piezometers installed separately to form a monitoring network adequate for the
purposes of an investigation
2.4
multi-level sampler
single installation for sampling groundwater from discrete depths within the sub-surface
NOTE The device can be driven directly into the ground, installed in a pre-existing borehole or installed in a purpose-drilled
hole. When installed in a borehole, integral packers are used to isolate individual sample ports.
2.5
aquifer
geological formation (bed or stratum) of permeable rock or unconsolidated material (e.g. sand and gravels) capable
of yielding significant quantities of water
2.6
aquitard
geologic stratum of formation of low permeability that impedes the flow of water between two aquifers
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2.7
saturated zone
part of an aquifer in which the pore spaces of the formation are completely water-saturated
2.8
unsaturated zone
part of an aquifer in which the pore spaces of the formation are not totally water-saturated
2.9
groundwater
water in the saturated zone and/or unsaturated zone of an underground geological formation or artificial deposit
such as made ground
2.10
perched water table
isolated body of groundwater, which is limited in lateral and vertical extent, located within the unsaturated zone
overlying a much more extensive groundwater body
2.11
matrix potential
combination of forces, independent of gravity, acting on soil water (water contained within the pores of a soil/rock
matrix) that exist as a result of the attraction of solid surfaces to water and the attraction of water molecules to each
other
NOTE Generally, the smaller the particle size, the higher the matrix potential.
2.12
check valve
mechanical valve which allows fluids to pass in only one direction
NOTE The pressure of fluids flowing through the valve in one direction has the effect of opening the valve and in the other
of closing it.
2.13
receptor
entity that is vulnerable to the adverse effect(s) of a hazardous substance or agent
EXAMPLES Human, animal, water, vegetation, building services, etc.
2.14
packer
device or material for temporarily isolating specified vertical sections within boreholes in which to perform
groundwater sampling from discrete zones or locations within the borehole or aquifer
2.15
hydraulic conductivity
property of a water-bearing formation that relates to its capacity to transmit water through its internal,
interconnected pathways
2.16
effective porosity
proportion of saturated openings or pores within a water-bearing formation which contribute directly to the flow of
groundwater
NOTE Effective porosity is represented as the ratio of this volume of pore space to the total volume of rock.
2.17
field capacity
maximum amount of water that a soil or rock can retain after gravitational water has drained away
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2.18
dense non-aqueous phase liquids
DNAPL
organic compounds that have a low water solubility and a density greater than that of water
EXAMPLES Chlorinated hydrocarbons such as trichloroethane.
2.19
light non-aqueous phase liquid
LNAPL
organic compounds that have a low water solubility and a density less than that of water
EXAMPLE Petroleum products.
3 Sampling strategy and programme design
3.1 General
Groundwater sampling can be carried out as a single exercise or as part of a larger site or environmental
investigation. Regardless of the purpose, a rational approach should be taken that clearly defines the objectives,
determines the level of information needed and identifies the various stages of the investigation.
It should be noted that, normally, groundwater sampling from the saturated zone alone cannot fully assess the level
of contamination of a site in situations where an unsaturated zone of considerable thickness exists. The potential
consequence of ignoring the unsaturated zone is that the unsaturated zone and groundwater system could become
extensively contaminated before any tangible evidence of leakage or contamination is evident in samples collected
from below the water table.
3.2 Selection of sampling point location
The location of monitoring installations and the design of the network for sampling groundwater from (potentially)
contaminated sites should take account of the following:
� the hydrogeological setting of the investigation site;
� the past and future use(s) of the site;
� the purpose of the exercise;
� the likely contaminants;
� the extent of contamination.
All of these factors should be considered during the preliminary stages of the site investigation programme to
enable the most appropriate and effective sampling programme to be designed. This information can be obtained
by examining all available information held by site owners (or their agents), local, regional and national regulatory
agencies and other data holders. Table 1 provides an overview of the steps involved in planning an investigation
strategy and for sampling groundwater from sites that are potentially contaminated.
In addition to the scientific requirements, other factors can influence the location of sampling points. These include
practical, environmental and safety considerations such as the ground slope, proximity of underground services
(gas pipes, electricity cables etc) and overhead clearance for drilling rigs and other sampling devices.
To establish whether migration of contaminants is occurring and determining the direction and rate of this
migration, monitoring points should be located inside and outside the contaminated area and both up and down the
hydraulic gradient. A greater number of sample points should be positioned down gradient, both inside and outside
of any contaminant plume.
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Where site analysis indicates that the site is underlain by complex geology or that contaminants with a broad range
of physical and chemical properties are likely to be present, an increased number of monitoring points should be
installed for adequate characterization of the contaminant distribution. In addition to investigating the lateral
variation caused by heterogeneity, the sampling strategy should also be designed to investigate any vertical
variations.
[9]
Table 1 — Procedural steps for sampling groundwater (adapted from )
Step
(with reference to other ISO Procedure Essential elements Notes
standards)
Investigation/monitoring Collation of available data Identify data sources Geological, geochemical and
strategy (ISO 5667-1) hydrogeological characterization
Desk study
Develop conceptual model
See 3.2, 3.3 and 3.4
Design borehole/sampling point
Reconnaissance survey
network and sampling programme
Facility installation Installation of monitoring points Borehole design, material Seeclause4
by drilling selection and installation technique
See 5.1
Well cleaning and development
Well inspection Hydrologic measurements Water level measurements Hydrogeological characterization
Hydraulic testing
Well purging Removal or isolation of stagnant Representative groundwater See 5.1
water
Verification of representative See 5.2
Determination of well-purging
groundwater
parameters (e.g. EC, pH,
temperature, redox potential)
Sample collection Sample collection by appropriate See 4.2 and 4.3
Filtration mechanism
Field determinations
Unfiltered Field filtered Field determination of sensitive
(ISO 5667-2, ISO 5667-11,
sample sample parameters, pH, electrical
ISO 5667-3)
conductivity, temperature, redox
potential, dissolved oxygen as
appropriate
Organics (all) Alkalinity/pH Head-space free samples See 5.4, 5.5 and 5.6
Dissolved gases Dissolved trace Minimal aeration or de-
metals for pressurization
specific
geochemical
information
Sensitive Sulfide and other Minimal air contact Blanks and spiked samples
inorganic sensitive should be prepared in accordance
species, e.g. inorganics with ISO 5667-14
nitrite,
ammonium,
iron(II)
Tracer metals for Major cations Sample preservation
mobile (colloidal) and
loads anions
Storage and transport of Minimal loss of sample integrity See 5.7, clauses 6, 7 and 8
samples (ISO 5667-3) prior to analysis
Care should be taken when identifying the prevailing flow regime as localized recharge to the subsurface can alter
the regional hydraulic gradient. This can result in groundwater flow and contaminant transportation in a direction
that is contrary to flow imposed by the regional gradient. Dense non-aqueous phase liquids (DNAPLs) can also
move in a different direction and at a different rate to that of groundwater because their chemical properties are
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different to those of water. Their migration is also affected by the geological structure of the low permeability layer
underlying the saturated aquifer.
Light non-aqueous phase liquids (LNAPLs) also have different chemical properties to those of water and their
migration and distribution will be affected by the geological structure and chemical interactions within the
unsaturated zone and zone of water table fluctuation.
Where sampling is aimed at providing an early warning of the impact of contaminants on receptors, monitoring
points should be located between the contaminant source (and plume) and the potential receptors as well as within
the zone of contamination, e.g. at landfill sites, monitoring points should be established around the outside of, but
close to, the landfill.
Sample points within the zone of contamination and outside (both up and down the hydraulic gradient) should be
installed to measure performance and effectiveness of remediation and for demonstrating compliance to licence
conditions.
3.3 Groundwater parameter selection
The parameters selected for analysis should reflect the nature of the investigation and/or the former, current and
proposed future use of the site. In some cases, certain contaminants will be the subject of national regulations.
Focussing only on these, however, could be inadequate for providing the complete picture of contamination under
different geochemical and hydrogeological conditions. For example, where organic contaminants are susceptible to
degradation, the list of analytes should also include the degradation products, which in some cases can also be
hazardous. An example of this is the degradation of trichloroethylene (TCE), a DNAPL. One of its potential
degradation products is vinyl chloride, a relatively soluble and highly volatile compound.
Consideration should also be given to baseline or natural groundwater concentrations. Elevated concentrations can
already be present in the environment being investigated as a result of natural sources of contamination.
3.4 Sampling frequency
The frequency of sampling depends on the objectives of the investigation. If the investigation is designed to map an
established contaminant plume, a single-event sampling exercise may be used. In this case, sampling should be
completed as rapidly as possible to minimize the effects of temporal variation. Where the development of a plume
is to be monitored and/or the impacts on groundwater resources considered, the frequency should be based on the
prevailing hydrogeological and environmental conditions, the objectives of the study and the contaminants present.
Where monitoring is required to provide early warning, where there are compliance issues or for performance
assessment of remedial measures, in general, a recommended minimum sampling frequency is quarterly for most
chemical constituents (e.g. major ions, etc.) and monthly for those that are more mobile and reactive (e.g. VOCs
and dissolved gases).
However, where environmental conditions indicate that changes can occur more rapidly, more frequent sampling
should be carried out. In these cases, the exact frequency should be determined by examination of all influencing
natural and artificial factors. Examples of short-term influencing factors include tidal influences and localized rainfall
as well as ground disturbance caused by ground engineering activities.
One example of how sampling frequency can be determined using prevailing hydrogeological properties (including
hydraulic gradient, hydraulic conductivity and effective porosity) is shown in Figure 1. Relevant hydrogeological
[8]
parameters have been used to develop a nomogram, which has been adapted from to include the effects of
dispersion, for rapid estimation of sampling frequency. Dispersion has the effect of distributing the contaminant
both along the flow path and perpendicular to it. The modification applied leads to a 10 % increase in sample
frequency. A worked example is described in annex A.
Other environmental conditions can also influence the temporal distribution and concentration of contaminants in
groundwater and soil water and these should be considered during development of the sampling strategy.
Seasonal and more frequent variations in weather and climate can influence the rate of infiltration of contaminants
through the unsaturated zone. A rise in water table can also lead to the release (or re-release) of contaminants into
the groundwater and/or bring the contaminant source closer to the groundwater.
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����
DN DN
F�� 0,1
����
��86 400Ki ��86 400Ki
[8]
Figure 1 — Nomogram for estimating sampling frequency (from )
4 Types of monitoring installation
4.1 General
Installations suitable for groundwater monitoring typically involve placement of access tubes for portable sampling
devices or burial of sensors or samplers in situ. These installations may be positioned within the saturated zone
(below the water table) or above it (unsaturated zone). In addition to sampling groundwater, installations below the
water table can be used to measure water levels and installations above the water table can measure soil gas and
soil moisture content.
4.2 Unsaturated zone monitoring
4.2.1 Introduction
Sampling techniques that are used for collection of groundwater from the unsaturated zone can be divided into two
types:
� solid sampling followed by extraction of groundwater (pore fluids);
� unsaturated pore fluid sampling.
4.2.2 Extraction from solid samples
4.2.2.1 General
The extraction of pore fluids from solid samples is the most widely used method for sampling groundwater in the
unsaturated zone. Collection of solid samples as part of this method can also allow useful geological information to
be obtained. There are two broad categories of solid sampling methods: hand-operated and power-operated.
Table 2 lists a range of suitable techniques that can be used for extracting solid samples for pore fluid collection.
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The removal of solid samples from the ground is however a destructive form of sampling that, although necessary,
does not allow subsequent re-sampling from the same location. It therefore precludes taking samples at a later
date for analysis of trends.
Table 2 — A range of methods suitable for soil and rock sampling
Drilling
Method Soil/rock type Maximum depth Diameter range
a
fluid/flush
Trial pitting
Hand- All soil types and Maximum6m(but no Depends on depth of
powered unconsolidated rocks generally to 4 m) pit and soil/rock type
Tube Hand- Soils, clay and fine grained
sampling
powered unconsolidated geological Approximately 10 m no 25 m
...
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