ASTM D6001/D6001M-20

Standard Guide for Direct-Push Groundwater Sampling for Environmental Site Characterization

SIGNIFICANCE AND USE
5.1 Direct-push groundwater sampling and profiling are economical methods for obtaining discrete interval groundwater quality samples in many soils and unconsolidated formations without the expense of permanent monitoring well installation (1-10).4 Many of these devices can be used to profile groundwater quality or contamination and/or hydraulic conductivity with depth by performing repetitive sampling and testing events. DP groundwater sampling is often used in expedited site characterization (Practice D6235) and as a means to accomplish high resolution site characterization (HRSC) (11, 12). The formation to be sampled should be sufficiently permeable to allow filling of the sampler in a relatively short time. The zone to be sampled and/or slug tested can be isolated by matching sampler screen length to obtain discrete samples of thin saturated, permeable layers. Use of these sampling and hydraulic testing techniques will result in more detailed characterization of sites containing multiple aquifers. The field conditions, sampler design and data quality objectives should be reviewed to determine if development (Guide D5521/D5521M) of the screened formation is appropriate. The samplers do not have a filter pack designed to retain fines like conventional wells, but only a slotted screen or wire-mesh covered ports. So, obtaining low turbidity samples may be difficult or even impossible in formations with a significant proportion of fine-grained materials. With most systems turbidity will always be high so consult Guide D6564/D6564M if field filtration of samples is required. Discrete water sampling, combined with knowledge of location and thickness of target aquifers, may better define conditions in thin multiple aquifers than monitoring wells with long screened intervals that can intersect and allow for intercommunication of multiple aquifers (4, 6, 11-15). DP sampling performed without knowledge of the location and thickness of target aquifers can result in sampling...
SCOPE
1.1 This guide covers a review of methods for sampling groundwater at discrete points or in increments by insertion of groundwater sampling devices using Direct Push Methods (D6286/D6286M, see 3.3.2). By directly pushing the sampler, the soil is displaced and helps to form an annular seal above the sampling zone. Direct-push water sampling can be one time, or multiple sampling events. Knowledge of site specific geology and hydrogeologic conditions is necessary to successfully obtain groundwater samples with these devices.  
1.2 Direct-push methods of water sampling are used for groundwater quality and geohydrologic studies. Water quality and permeability may vary at different depths below the surface depending on geohydrologic conditions. Incremental sampling or sampling at discrete depths is used to determine the distribution of contaminants and to more completely characterize geohydrologic environments. These explorations are frequently advised in characterization of hazardous and toxic waste sites and for geohydrologic studies.  
1.3 This guide covers several types of groundwater samplers; sealed screen samplers, profiling samplers, dual tube sampling systems, and simple exposed screen samplers. In general, sealed screen samplers driven to discrete depth provide the highest quality water samples. Profiling samplers using an exposed screen(s) which are purged between sampling events allow for more rapid sample collection at multiple depths. Simple exposed screen samplers driven to a test zone with no purging prior to sampling may result in more questionable water quality if exposed to upper contaminated zones, and in that case, would be considered screening devices.  
1.4 Methods for obtaining groundwater samples for water quality analysis and detection of contaminants are presented. These methods include use of related standards such as; selection of purging and sampling devices (Guide D6452 and D6634/D6634M), samp...

General Information

• Status: Published
• Publication Date: 31-Aug-2020
• ICS: 13.060.10 - Water of natural resources
• Technical Committee: D18 - Soil and Rock
• Drafting Committee: D18.21 - Groundwater and Vadose Zone Investigations

Relations

• Refers: ASTM D6914/D6914M-16(2024) - Standard Practice for Sonic Drilling for Site Characterization and the Installation of Subsurface Monitoring Devices
• Effective Date: 15-Mar-2024
• Refers: ASTM D5876/D5876M-17(2024) - Standard Guide for Use of Direct Rotary Wireline Casing Advancement Drilling Methods for Geoenvironmental Exploration and Installation of Subsurface Water-Quality Monitoring Devices
• Effective Date: 15-Mar-2024
• Refers: ASTM D6564/D6564M-17(2024) - Standard Guide for Field Filtration of Groundwater Samples
• Effective Date: 01-Feb-2024
• Refers: ASTM D6914/D6914M-16(2024) - Standard Practice for Sonic Drilling for Site Characterization and the Installation of Subsurface Monitoring Devices
• Effective Date: 01-Jan-2024
• Refers: ASTM D5876/D5876M-17(2024) - Standard Guide for Use of Direct Rotary Wireline Casing Advancement Drilling Methods for Geoenvironmental Exploration and Installation of Subsurface Water-Quality Monitoring Devices
• Effective Date: 01-Jan-2024
• Refers: ASTM D6517-18(2023) - Standard Guide for Field Preservation of Ground Water Samples
• Effective Date: 01-Nov-2023
• Refers: ASTM D6452-18(2023) - Standard Guide for Purging Methods for Wells Used for Ground Water Quality Investigations
• Effective Date: 01-Nov-2023
• Refers: ASTM D6089-19(2023) - Standard Guide for Documenting a Groundwater Sampling Event
• Effective Date: 01-Nov-2023
• Refers: ASTM D3740-23 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Nov-2023
• Refers: ASTM D5778-20 - Standard Test Method for Electronic Friction Cone and Piezocone Penetration Testing of Soils
• Effective Date: 01-Jun-2020
• Refers: ASTM D6286/D6286M-20 - Standard Guide for Selection of Drilling and Direct Push Methods for Geotechnical and Environmental Subsurface Site Characterization
• Effective Date: 01-May-2020
• Refers: ASTM D5088-20 - Standard Practice for Decontamination of Field Equipment Used at Waste Sites
• Effective Date: 01-May-2020
• Refers: ASTM D3740-19 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Oct-2019
• Refers: ASTM D6089-19 - Standard Guide for Documenting a Groundwater Sampling Event
• Effective Date: 01-Aug-2019
• Refers: ASTM D4448-01(2019) - Standard Guide for Sampling Ground-Water Monitoring Wells
• Effective Date: 01-Feb-2019

Overview

ASTM D6001/D6001M-20: Standard Guide for Direct-Push Groundwater Sampling for Environmental Site Characterization provides comprehensive guidelines for obtaining groundwater samples using direct-push (DP) methods. Developed by ASTM International, this standard outlines best practices for discrete, cost-effective groundwater sampling in various soils and unconsolidated formations, without the need for installed monitoring wells. This guide is valuable for environmental consultants, hydrogeologists, and site remediation professionals seeking efficient and high-resolution site characterization, especially for hazardous waste and geohydrologic studies.

Key focus areas include method selection, device operation, quality assurance, and addressing site-specific geologic and hydrogeologic conditions to guarantee representative groundwater sampling results.

Key Topics

• Direct-Push Groundwater Sampling Techniques

  • Guidance for selecting and implementing DP groundwater samplers
  • Covers sealed screen samplers, profiling samplers, dual tube systems, and exposed screen samplers
  • Strategies to avoid cross-contamination and optimize sampling accuracy

• Discrete and Incremental Sampling

  • Methods for collecting high-resolution groundwater samples at specific intervals or depths
  • Approaches for identifying contaminant distribution and aquifer characteristics

• Site Characterization

  • Application in expedited site characterization and high-resolution site investigations
  • Use in hazardous waste site assessments and geohydrologic studies

• Quality and Data Management

  • Ensuring representative sample quality through appropriate equipment and protocols
  • Guidance on field handling, purging, development, and filtration to reduce sample turbidity and improve data reliability
  • Reference to related standards for sample handling, shipping, and documentation

• Device and Soil Compatibility

  • Guidance on selecting sampling approach based on soil permeability, formation, and intended data quality
  • Considerations for difficult driving conditions and equipment limitations

Applications

The ASTM D6001/D6001M-20 guide is widely used in various applications, including:

• Environmental Site Assessments

  • Rapid assessment of groundwater contamination at hazardous and toxic waste sites
  • Identification of contamination hotspots, aquifer boundaries, and potential migration pathways

• High-Resolution Site Characterization (HRSC)

  • Collection of discrete interval samples to delineate groundwater quality across multiple aquifers or within heterogeneous soils
  • Support for conceptual site model development and risk assessment

• Hydraulic Conductivity Testing

  • Facilitating performance of slug tests and hydraulic profiling to measure aquifer permeability by depth

• Remediation Design and Monitoring

  • Informing placement of permanent groundwater monitoring wells or guiding remedial action planning
  • Evaluating temporal changes in groundwater conditions through multiple sampling events

• Regulatory Compliance

  • Collecting defensible data for regulatory reporting and permitting processes

Related Standards

The ASTM D6001/D6001M-20 references and complements a number of other key ASTM standards, including:

• D5521/D5521M: Guide for Development of Groundwater Monitoring Wells in Granular Aquifers
• D6235: Practice for Expedited Site Characterization at Hazardous Waste Sites
• D6634/D6634M: Guide for Selection of Purging and Sampling Devices for Groundwater Monitoring Wells
• D4448: Guide for Sampling Ground-Water Monitoring Wells
• D6452: Guide for Purging Methods for Ground Water Quality Investigations
• D6564/D6564M: Guide for Field Filtration of Groundwater Samples
• D6771: Practice for Low-Flow Purging and Sampling
• D6724/D6724M & D6725/D6725M: Installation of Direct Push Groundwater Monitoring Wells
• D7242/D7242M: Practice for Field Pneumatic Slug Tests
• D6067/D6067M: Practice for Electronic Piezocone Penetrometer Testing

These related standards collectively support robust, reliable, and regulatory-compliant groundwater sampling for environmental and geohydrologic site characterization projects.

For effective use, practitioners should consult ASTM D6001/D6001M-20 alongside relevant standards to adapt methods for specific site conditions and project goals.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D6001/D6001M − 20
Standard Guide for
Direct-Push Groundwater Sampling for Environmental Site
Characterization
This standard is issued under the fixed designation D6001/D6001M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* D6771) and sampling preparation and handling (Guides
D5903, D6089, D6517, D6564/D6564M, and D6911).
1.1 This guide covers a review of methods for sampling
groundwater at discrete points or in increments by insertion of 1.5 When appropriately installed and developed many of
groundwater sampling devices using Direct Push Methods these devices may be used to perform pneumatic slug testing
(D6286/D6286M, see 3.3.2). By directly pushing the sampler, (PracticeD7242/D7242M)toquantitativelyevaluateformation
thesoilisdisplacedandhelpstoformanannularsealabovethe hydraulic conductivity over discrete intervals of unconsoli-
samplingzone.Direct-pushwatersamplingcanbeonetime,or dated formations. These slug tests provide reliable determina-
multiple sampling events. Knowledge of site specific geology tions of hydraulic conductivity and can be performed after
and hydrogeologic conditions is necessary to successfully water quality sampling is completed.
obtain groundwater samples with these devices.
1.6 Direct-push water sampling is limited to unconsolidated
formations that can be penetrated with available equipment. In
1.2 Direct-push methods of water sampling are used for
groundwater quality and geohydrologic studies. Water quality strong soils damage may result during insertion of the sampler
from rod bending or assembly buckling. Penetration may be
and permeability may vary at different depths below the
surface depending on geohydrologic conditions. Incremental limited, or damage to samplers or rods can occur in certain
groundconditions,someofwhicharediscussedin5.7.Drilling
sampling or sampling at discrete depths is used to determine
the distribution of contaminants and to more completely equipment such as sonic drilling (Practice D6914/D6914M)or
rotary drilling (Guide D6286/D6286M) can be used to advance
characterize geohydrologic environments. These explorations
are frequently advised in characterization of hazardous and holes past formations difficult to penetrate using typical Direct
Push equipment. Some soil formations do not yield water in a
toxic waste sites and for geohydrologic studies.
timely fashion for direct-push sampling. In the case of unyield-
1.3 This guide covers several types of groundwater sam-
ing formations, direct-push soil sampling can be performed
plers; sealed screen samplers, profiling samplers, dual tube
(Guide D6282/D6282M).
sampling systems, and simple exposed screen samplers. In
general, sealed screen samplers driven to discrete depth pro- 1.7 Direct push water sampling with one-time sealed screen
samplers can also be performed using cone penetrometer
vide the highest quality water samples. Profiling samplers
usinganexposedscreen(s)whicharepurgedbetweensampling equipment (Guide D6067/D6067M).
events allow for more rapid sample collection at multiple
1.8 This guide does not address installation of permanent
depths. Simple exposed screen samplers driven to a test zone
water sampling systems such as those presented in Practice
with no purging prior to sampling may result in more ques-
D5092/D5092M. Direct-push monitoring wells for long term
tionable water quality if exposed to upper contaminated zones,
monitoring are addressed in Guide D6724/D6724M and Prac-
and in that case, would be considered screening devices.
tice D6725/D6725M.
1.4 Methods for obtaining groundwater samples for water
1.9 Units—The values stated in either SI units or inch-
quality analysis and detection of contaminants are presented.
pound units [presented in brackets] are to be regarded sepa-
These methods include use of related standards such as;
rately as standard.The values stated in each system may not be
selection of purging and sampling devices (Guide D6452 and
exact equivalents; therefore, each system shall be used inde-
D6634/D6634M), sampling methods (Guide D4448 and
pendentlyoftheother.Combiningvaluesfromthetwosystems
may result in nonconformance with the standard. Reporting of
test results in units other than SI shall not be regarded as
This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rock
nonconformance with this standard.
and is the direct responsibility of Subcommittee D18.21 on Groundwater and
Vadose Zone Investigations.
1.10 Allobservedandcalculatedvaluesshallconformtothe
Current edition approved Sept. 1, 2020. Published November 2020. Originally
guidelines for significant digits and rounding established in
approved in 1996. Last previous edition approved in 2012 as D6001 – 05(2012).
DOI: 10.1520/D6001_D6001M-20. Practice D6026, unless superseded by this standard.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6001/D6001M − 20
1.11 This standard does not purport to address all of the D5903 Guide for Planning and Preparing for a Groundwater
safety concerns, if any, associated with its use. It is the Sampling Event
responsibility of the user of this standard to establish appro-
D6026 Practice for Using Significant Digits in Geotechnical
priate safety, health, and environmental practices and deter-
Data
mine the applicability of regulatory limitations prior to use.
D6067/D6067M PracticeforUsingtheElectronicPiezocone
1.12 This guide offers an organized collection of informa-
Penetrometer Tests for Environmental Site Characteriza-
tion or a series of options and does not recommend a specific
tion and Estimation of Hydraulic Conductivity
course of action. This document cannot replace education or
D6089 Guide for Documenting a Groundwater Sampling
experience and should be used in conjunction with professional
Event
judgment. Not all aspects of this guide may be applicable in all
D6187 Practice for Cone Penetrometer Technology Charac-
circumstances. This ASTM standard is not intended to repre-
terization of Petroleum Contaminated Sites with Nitrogen
sent or replace the standard of care by which the adequacy of
Laser-Induced Fluorescence (Withdrawn 2019)
a given professional service must be judged, nor should this
D6235 Practice for Expedited Site Characterization of Va-
document be applied without consideration of a project’s many
dose Zone and Groundwater Contamination at Hazardous
unique aspects. The word “Standard” in the title of this
Waste Contaminated Sites
document means only that the document has been approved
D6452 Guide for Purging Methods for Wells Used for
through the ASTM consensus process.
Ground Water Quality Investigations
1.13 This international standard was developed in accor-
D6517 Guide for Field Preservation of Ground Water
dance with internationally recognized principles on standard-
Samples
ization established in the Decision on Principles for the
D6564/D6564M Guide for Field Filtration of Groundwater
Development of International Standards, Guides and Recom-
Samples
mendations issued by the World Trade Organization Technical
D6634/D6634M Guide for Selection of Purging and Sam-
Barriers to Trade (TBT) Committee.
pling Devices for Groundwater Monitoring Wells
D6724/D6724M Guide for Installation of Direct Push
2. Referenced Documents
Groundwater Monitoring Wells
2.1 ASTM Standards:
D6725/D6725M Practice for Direct Push Installation of
D653 Terminology Relating to Soil, Rock, and Contained
Prepacked Screen Monitoring Wells in Unconsolidated
Fluids
Aquifers
D1586/D1586M Test Method for Standard Penetration Test
D6771 Practice for Low-Flow Purging and Sampling for
(SPT) and Split-Barrel Sampling of Soils
Wells and Devices Used for Ground-Water Quality Inves-
D2488 Practice for Description and Identification of Soils
tigations
(Visual-Manual Procedures)
D6911 Guide for Packaging and Shipping Environmental
D3740 Practice for Minimum Requirements for Agencies
Samples for Laboratory Analysis
Engaged in Testing and/or Inspection of Soil and Rock as
D7242/D7242M Practice for Field Pneumatic Slug (Instan-
Used in Engineering Design and Construction
taneous Change in Head) Tests to Determine Hydraulic
D4448 Guide for Sampling Ground-Water Monitoring Wells
Properties of Aquifers with Direct Push Groundwater
D4750 Test Method for Determining Subsurface Liquid
Samplers
Levels in a Borehole or Monitoring Well (Observation
D7352 Practice for Volatile Contaminant Logging Using a
Well) (Withdrawn 2010)
Membrane Interface Probe (MIP) in Unconsolidated For-
D5088 Practice for Decontamination of Field Equipment
mations with Direct Push Methods
Used at Waste Sites
D8037/D8037M PracticeforDirectPushHydraulicLogging
D5092/D5092M Practice for Design and Installation of
for Profiling Variations of Permeability in Soils
Groundwater Monitoring Wells
2.2 Drilling Methods:
D5314 Guide for Soil Gas Monitoring in the Vadose Zone
D5781/D5781M Guide for Use of Dual-Wall Reverse-
(Withdrawn 2015)
Circulation Drilling for Geoenvironmental Exploration
D5434 Guide for Field Logging of Subsurface Explorations
of Soil and Rock and the Installation of Subsurface Water Quality Monitor-
ing Devices
D5521/D5521M Guide for Development of Groundwater
Monitoring Wells in Granular Aquifers D5782 Guide for Use of Direct Air-Rotary Drilling for
D5778 Test Method for Electronic Friction Cone and Piezo- Geoenvironmental Exploration and the Installation of
cone Penetration Testing of Soils
Subsurface Water-Quality Monitoring Devices
D5783 Guide for Use of Direct Rotary Drilling with Water-
Based Drilling Fluid for Geoenvironmental Exploration
and the Installation of Subsurface Water-Quality Monitor-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
ing Devices
Standards volume information, refer to the standard’s Document Summary page on
D5784/D5784M Guide for Use of Hollow-Stem Augers for
the ASTM website.
3 Geoenvironmental Exploration and the Installation of
The last approved version of this historical standard is referenced on
www.astm.org. Subsurface Water Quality Monitoring Devices
D6001/D6001M − 20
D5875/D5875M Guide for Use of Cable-Tool Drilling and 3.3 Definitions of Terms Specific to This Standard:
SamplingMethodsforGeoenvironmentalExplorationand
3.3.1 assembly length, n—length of sampler body and riser
Installation of Subsurface Water Quality Monitoring De-
pipes.
vices
3.3.2 direct-push (DP) method, v—a subsurface exploration
D5876/D5876M Guide for Use of Direct Rotary Wireline
method by which drive rod, casing tube, sampling, and logging
Casing Advancement Drilling Methods for Geoenviron-
devices are pushed, driven, or vibrated into soils or unconsoli-
mental Exploration and Installation of Subsurface Water-
dated formations to be sampled or logged without rotary
Quality Monitoring Devices
drilling and removal of cuttings.
D6286/D6286M Guide for Selection of Drilling and Direct
3.3.2.1 Discussion—For the purposes of this guide, a sub-
Push Methods for Geotechnical and Environmental Sub-
surface exploration method that uses hand-held percussion
surface Site Characterization
driving devices, or hydraulic percussion, quasi static push, or
D6914/D6914M Practice for Sonic Drilling for Site Charac-
vibratory drive systems that are mounted to a truck, van,
terization and the Installation of Subsurface Monitoring
all-terrain vehicle, trailer, skid, or drill rig.
Devices
3.3.3 direct-push groundwater sampler, n—a sampler spe-
2.3 Soil Sampling:
cially designed for use with direct push methods to collect
D6282/D6282M Guide for Direct Push Soil Sampling for
groundwater from relatively pervious soils (aquifers).
Environmental Site Characterizations
3.3.4 exposed screen sampler, n—in drilling, a sampler with
3. Terminology
an exposed screen driven to the sampling depth that may be
exposed to cross contamination prior to the sampling.
3.1 Definitions:
3.1.1 For definitions of common technical terms in this
3.3.5 exposed screen length, n—the length of a screen open
standard, refer to Terminology D653.
or exposed to water bearing strata.
3.2 The definitions below are in Terminology D653, and as
3.3.5.1 Discussion—In some DP groundwater sampling de-
adopted from Practice D5092/D5092M on installation of
vices only a portion of the screen may be exposed to the
monitoring wells.
formation to target a discrete zone for sampling.
3.2.1 bailer, n—in wells, a hollow tubular receptacle used to
3.3.6 effective seal length, n—the length of soil above the
facilitate removal of fluid from a well or borehole.
samplerscreenthatisinintimatecontactwiththeriserpipeand
3.2.2 borehole, n—in drilling, an open or uncased subsur-
prevents connection of the screen with groundwater from
face hole, generally circular in plain view, created by drilling.
overlying zones.
3.2.2.1 Discussion—Normally,aboreholeisadvancedusing
3.3.7 grab groundwater sampling, v—in groundwater, the
an auger, a drill, or casing with or without drilling fluid, but for
process of rapidly collecting a water sample with minimal
this standard it is made using direct push methods (3.3.2).
purging or development using simple equipment like bailers or
3.2.3 casing, n—in drilling, pipe, finished in sections with
pumps at a specific time, location, and depth.
either threaded connections or beveled edges to be field
3.3.7.1 Discussion—Grab sampling is a rapid sampling
welded, which is installed temporarily or permanently to
event with little or no purging or development of the test zone,
counteract caving, to advance the borehole, or to isolate the
often using simple devices like a bailer or inertial pumps.
zone being monitored, or combination thereof.
3.3.8 incremental drilling and sampling, n—in drilling,
3.2.4 caving; sloughing, v—in drilling, the inflow of uncon-
insertion method where rotary drilling and sampling events are
solidated material into a borehole that occurs when the
alternated for incremental sampling. Incremental drilling is
borehole walls lose their cohesive strength.
often needed to penetrate harder or deeper formations.
3.2.5 centralizer, n—in drilling, a device that assists in the
3.3.9 groundwater profiling, v—the method of advancing a
centering of a casing or riser within a borehole or another
groundwater sampling device incrementally and collecting
casing.
discrete samples of groundwater at each depth interval.
3.2.6 PTFE tape, n—in drilling,jointsealingtapecomposed
3.3.10 percussion driving, v—insertion method where rapid
of polytetrafluorethylene.
3.2.6.1 Discussion—For sampling of (PFAS, 3.3.11), PTFE hammer impacts are performed to insert the sampling device
and the percussion is normally accompanied with application
tape may not be used in well assembly due to the potential for
cross contamination. of static down force.
3.2.7 slot, n—in well screen opening, slot openings have
3.3.11 PFAS, n—polyfluorinated alkyl substances: includes
been designated by numbers which correspond to the width of
PFOS (perfluorooctane sulfonate) and PFOA(perfluorooctano-
the openings in thousandths of an inch.
ate acid) that have very low detection levels, in parts per
3.2.7.1 Discussion—ANo. 10 slot screen, for example, is an
trillion for combined concentration in drinking water.
opening of 0.25 mm [0.010 in.].
3.3.11.1 Discussion—PFAS includes hundreds of poly fluo-
3.2.8 well screen, n—in wells, a device used to retain the rinatedcompounds,manyofwhicharecomponentsofaqueous
primary or natural filter pack; usually a cylindrical pipe with fire-fighting foams (AFFF) previously used at military and
openings of uniform width, orientation, and spacing. commercial airports. PFAS compounds have been used in
D6001/D6001M − 20
many industrial and commercial products. Polytetrafluorethyl- contamination and “drag down” of contaminants as the ex-
ene containing materials and products are excluded from use posed screens are advanced to increasing depths. Injection of
when PFAS sampling is conducted. clean water out of the screen(s) as the tools are advanced to
increasing depths may help reduce the drag down effect.
3.3.12 push depth, n—the depth below a ground surface
datum that the end or tip of the direct-push water sampling
4.3 Dual-tubegroundwatersystemsprovidefortheinsertion
device is inserted.
and removal of fresh screens at multiple depths as the outer
casing is incrementally advanced to depth. The system can be
3.3.13 sampler screen, n—a well screen mesh or slot system
used for one-time sampling events as a sealed screen sampler.
designed to filter coarse particles from the sampling test zone
However, a one-time sampling event when used for multiple
or ports of the direct push groundwater sampler.
vents and after soils sampling the water from previous sam-
3.3.14 sealed screen sampler, n—a groundwater sampler
pling intervals left in the outer casing as the exposed screen
where the sampler screen is sealed until the sampling depth is
tool string is advanced may lead to cross contamination. In
reached thus preventing exposure to groundwater from previ-
saturated sands formation heave may be difficult to control in
ous depths and accurate evaluation of water quality at the point
the dual tube sand formations systems without the addition of
of sampling.
excessive amounts of water to control the hydraulic head.
3.3.15 unconsolidated geologic materials, n—in
Dual-tube systems may be slug tested (Practice D7242/
groundwater, geology, or hydrogeology, a loosely aggregated
D7242M) to determine the hydraulic conductivity of the
solid (particulate) material of geologic origin (soil, sediments,
screened formation, following adequate development.
etc.).
4.4 Development of the screened formation and sampling
3.3.15.1 Discussion—Groundwater hydrologists, and
groundwater may be performed using a variety of tools and
geologists, use the terms unconsolidated formations, deposits,
methods depending on the design of the sampling device
sediments, units, materials, etc., to refer to the general term
(Guide D5521/D5521M). Development is most often per-
“soil” including other soils (alluvium, glacial till, etc.) as
formed with an inertial check valve in the small diameter
defined in D653. These terms are often found in groundwater
piezometers having an open annulus to the surface.
standards applied to aquifers. Unconsolidated materials are
Occasionally,amini-surgeblockorsimilardevicemaybeused
non-lithified, typically lacking cementation of individual par-
for development of these types of tools. Sampling of the open
ticles (clay, silt sand, gravel, etc.). The term “unconsolidated”
annulus tools may be performed with devices such as a
should not be confused with geotechnical terms of the degree
mini-bailer, inertial pump, peristaltic pump or small diameter
of soil consolidation (over, normally, under-consolidated) as
bladder pump (Guide D6634/D6634M). Review project data
defined in D653.
qualityobjectivestodeterminetheappropriatesamplingdevice
3.4 Acronyms:
and method. DP groundwater profiling devices often have
3.4.1 DP—Direct Push methods (3.3.2).
tubing, integrated pumps and/or trunk lines in the annulus of
the drive casing. This precludes performance of typical forma-
4. Summary of Guide
tion development procedures, other than pumping. The profil-
4.1 Direct-push groundwater sampling may be performed
ing devices are often purged and sampled with a peristaltic
using different procedures depending on the device design and
pump or integrated downhole pump. The integrated pumps
purpose of the investigation. One single-tube procedure con-
may be of various design.
sists of pushing a sealed protected screen sampler to a known
depth,openingthesamplerscreenoveraspecifiedinterval,and
5. Significance and Use
samplinggroundwaterfromtheinterval.Thesingletubesealed
5.1 Direct-push groundwater sampling and profiling are
screen method will provide the highest integrity water quality
economical methods for obtaining discrete interval groundwa-
samples. A sampler, often with constant outside diameter is
ter quality samples in many soils and unconsolidated forma-
inserted directly into the soil by percussion hammering and/or
tions without the expense of permanent monitoring well
static push until sufficient riser pipe is seated into the soil to
installation (1-10). Many of these devices can be used to
ensure a seal. Sealed screens can be exposed by retraction of
profile groundwater quality or contamination and/or hydraulic
riser pipes. While the riser is seated in the soil, water samples
conductivity with depth by performing repetitive sampling and
can be taken, and water injection or pressure measurements
testing events. DP groundwater sampling is often used in
may be performed. Following adequate development many of
expedited site characterization (Practice D6235) and as a
these devices can be slug tested using pneumatic methods
means to accomplish high resolution site characterization
(Practice D7242/D7242M) to obtain data about formation
(HRSC) (11, 12). The formation to be sampled should be
hydraulic conductivity.
sufficiently permeable to allow filling of the sampler in a
4.2 Profiling samplers allow the operator to collect samples
relativelyshorttime.Thezonetobesampledand/orslugtested
of groundwater at multiple, increasing depths as the tool is
can be isolated by matching sampler screen length to obtain
incrementally advanced. These exposed screen samplers may
discrete samples of thin saturated, permeable layers. Use of
be advanced as water is injected into the formation through the
screen(s) or port(s). The injection pressure and flow rate of the
water may be monitored to evaluate formation permeability as
The boldface numbers in parentheses refer to a list of references at the end of
some devices are advanced. These devices are subject to cross this standard.
D6001/D6001M − 20
these sampling and hydraulic testing techniques will result in 5.3 Slug tests can be performed with several of the DP
more detailed characterization of sites containing multiple groundwater samplers (D7242/D7242M) to determine hydrau-
aquifers. The field conditions, sampler design and data quality lic conductivity over discrete intervals. Development of the
objectives should be reviewed to determine if development screened interval should be conducted to assure that formation
flow into and out of the device is representative of natural
(Guide D5521/D5521M) of the screened formation is appro-
priate.Thesamplersdonothaveafilterpackdesignedtoretain formation conditions. Development with a simple inertial
pumptosurgeandpurgetheformationisoftenadequate.Other
fines like conventional wells, but only a slotted screen or
wire-mesh covered ports. So, obtaining low turbidity samples methods for development (D5521/D5521M) may be advised
depending on field conditions and data quality objectives.
may be difficult or even impossible in formations with a
significant proportion of fine-grained materials. With most
5.4 Water sampling chambers may be sealed to maintain in
systems turbidity will always be high so consult Guide
situ pressures and to allow for pressure measurements and
D6564/D6564M if field filtration of samples is required.
permeability testing (Practice D7242/D7242M) (6, 13, 19).
Discretewatersampling,combinedwithknowledgeoflocation
Sealing of samples under pressure may reduce the possible
andthicknessoftargetaquifers,maybetterdefineconditionsin
volatilization of some organic compounds. Field comparisons
thinmultipleaquifersthanmonitoringwellswithlongscreened
may be used to evaluate any systematic errors in sampling
intervalsthatcanintersectandallowforintercommunicationof
equipments and methods. Comparison studies may include the
multipleaquifers (4, 6, 11-15).DPsamplingperformedwithout
need for pressurizing samples, or the use of vacuum to extract
knowledge of the location and thickness of target aquifers can
fluids more rapidly from low hydraulic conductivity soils
result in sampling of the wrong aquifer or penetration through
(8.2.3.1(2)).
confining beds. Results from DP explorations can be used to
5.5 DP groundwater profiling tools (7, 8, 10, 20, 21) allow
develop conceptual site models, guide placement of permanent
the investigator to sample groundwater at multiple depths
groundwater monitoring wells, and direct remediation efforts.
during incremental advancement of the device. Clean water is
These devices are often used under dynamic work plans (11,
injected through the screen(s) or port(s) of these tools to keep
16) to complete site characterizations in a single mobilization.
the screens open and rinsed as advancement proceeds. Con-
However, multiple sampling events can be performed to depict
cernsforcrosscontaminationandcontaminantdragdownmust
conditions over time or refine earlier work if needed.
be considered. Some tools have an inline pressure transducer
5.2 Targeting Aquifer Sample Test Zones for Accurate
either above grade or down hole to monitor pressure required
Sampling—As with any investigation it is important to phase
to inject water into the formation during advancement. The
the investigation such that target intervals for groundwater
pressure injection log may be used to guide selection of
sampling are accurately located. For sites that allow surface
permeable zones for sampling. When the injection flow rate is
push of the sampling device, discrete water sampling is often
also measured, estimates of formation permeability may be
performed in conjunction with the cone penetration test (Test
calculated.
Method D6067/D6067M) (4-6, 13, 14) or continuous soil
5.6 Degradation of water samples during handling and
sampling (Guide D6282/D6282M) which is often used for
transport can be reduced if discrete water sampling events with
stratigraphic mapping of aquifers and to delineate high-
sealed screen samplers are combined with real time field
permeability zones for sampling. Alternately, resistivity
analysis of potential contaminants. In limited studies, research-
logging, or injection logging (Practice D8037/D8037M) may
ers have found that the combination of discrete sealed screen
be used to assess formation permeability and lithology prior to
sampling with onsite field analytical testing provide accurate
the groundwater sampling or profiling activities to guide
data of aquifer water quality conditions at the time of testing
selection of sampling intervals (10, 15, 17). In such cases, DP
(4, 6). DP water sampling with exposed screen sampling
water sampling is normally performed close to previous test
devices, which may require development or purging, are
holes.Incomplexdepositionalenvironments (12),thinaquifers
consideredasscreeningtoolsdependingonprecautionsthatare
may vary in continuity such that water sampling devices may
taken during testing.
not intersect the same layer at equivalent depths as companion
HPT, cone penetrometer, or electrical resistivity profiling
5.7 In difficult driving conditions, penetrating to the desired
soundings.
depth to make sure of sealing of the sampler screen may not be
5.2.1 When volatile organic contaminants (VOC) such as possible. If the screen cannot be inserted into the formation
trichloroethylene (TCE) or benzene are present in the with an adequate seal, the water-sampling event would require
subsurface, logging with the membrane interface probe (MIP) sealing in accordance with Practice D5092/D5092M to isolate
(Practice D7352) may be performed prior to groundwater the aquifer. Selection of the appropriate equipment and meth-
sampling. MIP logs identify where significant concentrations ods to reach required depth at the site of concern should be
of many VOCs are present and may be used to guide selection made in consultation with experienced operators or manufac-
of groundwater sampling locations, depths and intervals (17). turers. If there is no information as to the subsurface
When petroleum fuels are present in the subsurface laser conditions, initial explorations consisting of penetration-
induced fluorescence (LIF) (Practice D6187) or the Optical resistance tests, such as Test Method D6067/D6067M, resis-
Imaging Profiler (OIP) (18) may be used to identify where tivity profiling, or DP logging with the injection logging
significant petroleum contamination is present to assist in system (Practice D8037/D8037M) to perform trials can be
guiding selection of sample locations and depths. performed to select the appropriate testing system.
D6001/D6001M − 20
5.7.1 Typical penetration depths for a specific equipment etc.) to stability is often used to document when representative
configuration depend on many variables. Some of the variables water is being purged from a sampling interval (Practice
are the driving system, the diameter of the sampler and riser D6771).
pipes, and the resistance of the materials.
5.9 Bottom-up profiling by driving a DP groundwater sam-
5.7.2 Certain subsurface conditions may prevent sampler
pler to the base of the formation and retracting incrementally,
insertion. Penetration is not possible in hard rock and some-
while the screen is exposed, for sampling at decreasing depths
timesnotpossibleinsofterrockssuchasclaystonesandshales.
should be avoided as this may lead to cross contamination and
Coarse particles such as gravels, cobbles, and boulders may be
inaccurate contaminant distribution information. Slug tests
difficult to penetrate or cause damage to the sampler or riser
shouldnotbeperformedbybottom-upprofilingasthereispoor
pipes. Cemented soil zones may be difficult to penetrate
or no control on the length of formation being tested under
depending on the strength and thickness of the layers. If layers
these conditions.
are present that prevent DP from the surface, then rotary or
5.10 Screens designed and deployed in dual tube use are
percussion drilling methods (Guide D6286/D6286M) can be
generally designed for use inside the dual tubing and overdriv-
employed to advance a boring through impeding layers to
ing the screen past the casing can damage the sampler screen
reach testing zones.
and subsequent exposed screen samples would be subject to
5.7.3 Driving systems are generally selected based on test-
cross contamination. Use equipment according to manufac-
ing depths and the materials to be penetrated. For systems
tures instructions.
usingprimarilystaticreactionforcetoinsertthesampler,depth
NOTE 2—The quality of the result produced by this standard is
will be limited by the reaction weight of the equipment or
dependent on the competence of the personnel performing it, and the
suitability of the equipment and facilities used. Practitioners that meet the
anchoring stability and penetration resistance of the material.
criteria of Practice D3740 are generally considered capable of competent
The ability to pull back the rod string is also a consideration.
and objective testing/sampling/inspection/etc. Users of this standard are
Impactorpercussionsoilprobinghasanadvantageofreducing
cautioned that compliance with Practice D3740 does not in itself assure
the reaction weight required for penetration. Penetration capa-
reliable results. Reliable results depend on many factors; Practice D3740
bility in clays may be increased by reducing rod friction by
provides a means of evaluating some of those factors.
Practice D3740 was developed for agencies engaged in the testing
enlarging tips or friction reducers. However, over reaming of
and/or inspection of soils and rock.As such, it is not totally applicable to
the hole may increase the possibility of rod buckling and may
agencies performing this field practice. However, users of this practice
allow for communication of differing groundwater tables.
should recognize that the framework of Practice D3740 is appropriate for
Hand-held equipment is generally used on very shallow
evaluating the quality of an agency performing this practice. Currently
explorations, typically less than 5 m [15 ft] depth, but depths
there is no known qualifying national authority that inspects agencies that
perform this practice.
on the order of 10 m [30 ft] have been reached in very soft
lacustrine clays. Intermediate size driving systems, such as
6. Apparatus
small truck-mounted hydraulic-powered push and impact
drivers, typically work within depth ranges from 5 to 30 m [20
6.1 General—A direct-push sampling system consists of a
to 100 ft]. Larger DP machines may be capable of reaching 60
tip; well screen; chambers, if present; and drive rods (casing
m [200 ft] depending on subsurface conditions. Heavy static-
and/or riser pipes) extending to the surface. DPwater sampling
push cone penetrometer vehicles, such as 20 ton trucks,
equipment can be either with a sealed screen or exposed
typically work within depth ranges from 15 to 45 m [50 to 150
screen. There are also two types of drive systems, single tube
ft], and also reach depth ranges on the order of 100 m [300 ft]
and dual (double) tube (see 6.2.3).
in soft ground conditions. Guide D6286/D6286M shows depth
6.2 Sampler Types—Samplers with protected or sealed
ranges of other drilling equipment to attain greater depths.
screens depend on the seals to avoid exposure of the sampling
chamber or screen to contaminated soil or water from other
NOTE 1—Users and manufacturers cannot agree on depth ranges for
differentsoiltypes.Usersshouldconsultwithexperiencedlocalproducers
layers during advancement. Seals also should be maintained at
and manufacturers to determine depth capability for their specific site
each rod joint to prevent infiltration of water or fines from
conditions.
intervals above the desired sample interval where o-rings or
5.8 Combining multiple-sampling events in a single-sample plumbers’tape may be used. These devices can be considered
chamber (profiling) without decontamination (Practice D5088) as accurate point-source detectors. Single-tube sealed screen
is generally discouraged. In this application, purging of the devices are normally recovered and decontaminated between
screen or sampling chamber should be performed to make sure sampling events. In dual-tube systems the screen may be
of isolation of the sampling event. Purging should be per- installed after the outer casing is advanced to the desired
formed by removing several volumes of fluid until new sampling depth acting as a sealed screen sampler for one-time
chemical properties have been stabilized or elements are samplingevents.Ifthedualtubeisadvancedinasoilsampling
flushed with fluid of known chemistry. Purging requirements mode, and then a water sampler is taken, the sampler screen is
may depend upon the materials used in the sampler and the exposed to water in the casing. Exposed-screen samplers
sampler design (Guide D6634/D6634M). Rinsate samples may driven from the surface are subject to contaminant drag down
be collected and analyzed to assess concerns with carryover of and may require additional purging and development. Exposed
contaminants from overlying zones that are heavily contami- screen samplers in these modes are considered as screening
nated. Monitoring water quality parameters (pH, specific devices for profiling relative degrees of contamination. Ex-
conductance, dissolved oxygen, oxidation-reduction potential, posedScreenProfilingsamplersusedforgroundwaterprofiling
D6001/D6001M − 20
inject clean water during incremental advancement to mini- samplers have sample chambers designed to reduce volume
mize contaminant drag down and carryover and can provide and pressure changes in the sample to avoid possible loss of
accurate point source water quality sampling. volatile compounds (6, 13, 19). The need for pressurization is
6.2.1 Single-Tube Sealed-Screen Samplers—An example is dependent on the requirements of the exploration program and
shown in Fig. 1(22). This simple arrangement allows for grab should be evaluated by comparison studies in the field with
sampling through the riser pipe with minimal purging or simplersystemsallowingthesampletoequalizeatatmospheric
development if there is no leakage at the screen seals and riser pressure. There are different approaches to pressurizing the
pipe joints. If desired, development of these devices may be sample chamber including use of inert gas pressure or using
conducted prior to sampling. Development of the screened sealed systems. An example of a sealed vial-septum system is
intervals is required before slug testing is performed (D7242/ discussed by Berzins (6). In the sealed vial system, a septum is
D7242M). Fig. 2 shows a schematic of a DP water sampler puncturedwithahypodermicneedleconnectedtoasealedvial.
with a sealed screen and with the ability to work in the grab With this approach, the vial will contain both a liquid and gas
samplingmodeorbyallowingwatertoenterasamplechamber at aquifer pressure which could be problematic for volatile
in the sampler body (5). Most simple sample chambers allow organic compounds.
for flow through the chamber.When a flow through chambered 6.2.2 Profiling Sampler—Single Tube Exposed Screen—
sampler is opened, it is possible that the groundwater from the Some exposed screen samplers have been developed for
test interval can fill into the rods above the chamber. In those multiple sampling events (profiling) as an exposed screen or
cases, it may be advisable to add water of known chemistry sample ports are advanced incrementally (Fig. 3 and Fig. 4) (7,
into the rods prior to opening the screen. Some sealed-screen 8, 10, 20, 21). These multiple event “groundwater profilers”
The assembled Sampler is Extension rods are used to hold The tubing check valve Abandonment grout-
driven to the desired sampling the screen in position as the Cas- can be used to sample ing can be conducted
depth using standard rods. ing Puller Assembly is used to groundwater. to meet ASTM re-
retract the rods. quirements.
FIG. 1 Simple Sealed Screen Sampler (22)
D6001/D6001M − 20
Legend: Grab Sampling Legend: Water Sampling in Chamber
A Penetrometer closed while being driven into position. A Penetrometer closed while being driven into position.
B Tool opened and 5 foot screen telescopes into position for collec- B Cone separated and tool open to collect sample.
tion of hydrocarbon or water sample at the very top of the aquifer.
C Hydrocarbon sample being collected using bailer lowered through C Check valves closed as sample is retrieved within body of the
drive casing. tool.
FIG. 2 Sealed Screen Sampler Capable of Working in Grab or Chamber Sampling Modes (5)
inject clean water out of the ports during advancement to keep sampling. Some systems also monitor injection flow rate. The
the ports from clogging. Injection flow is stopped during injection pressure and flow rate may be used to estimate
sampling events. Purging the pump and sampling line between
formation permeability (Practice D8037/D8037M). Sampling
sampling events minimizes the potential for contaminant carry
can be conducted with various downhole pumps or with a
over. Collection and analysis of rinseate samples may help
peristaltic pump when the water level is sufficiently shallow.
document the presence of or lack of contaminant carry over as
6.2.3 Dual-Tube Groundwater Samplers—The Dual Tube
the devices are sampled at increasing depths. Some of these
system can be used in several modes. For the highest quality
devices have in-line pressure sensors to measure the pressure
water sample with, minimal cross contamination potential, the
required to inject water during advancement. Reviewing injec-
sample can be taken as a single event using the sealed drive tip
tion pressure logs during advancement can identify higher
driven to the target sampling depth. The Dual Tube system can
permeability (low pressure) zones for sampling and lower
also be used for profiling but groundwater remaining in the
permeability (high pressure) zones that will not yield water for
D6001/D6001M − 20
FIG. 3 Single-Tube Groundwater Profiling Tools Typically Inject Clean Water through Screened Ports on the Device During Advance-
ment to Prevent Clogging and Reduce the Potential for Contaminant Drag Down. Injection Flow is stopped during the purging-
sampling process. Down hole pumps or peristaltic pumps may be used for sampling (20).
casing from previous events may require extensive purging retrievable point in the shoe. Once at the desired depth, the
prior to the sampling events. inner drive rod and point are removed, and the screen and riser
6.2.3.1 Sealed Sampling Single Event—The installation of pipe are inserted down the outer casing. The outer casing is
dual-tube devices is often done by advancing a sealed outer retracted to set the screen in the formation for development,
casing to the desired depth interval equipped with an expend- sampling and slug testing, as desired. Once sampling and
able point (Fig. 5) (23). When at the desired depth a screen testingatthefirstintervaliscompletedthescreenandriserpipe
with riser pipe is lowered to the base of the outer casing. The are retrieved for decontamination. The inner drive rod and
outer casing is then retracted to expose the screen to the point are re-installed, and the dual tube system is advanced to
formation for development, sampling, and slug testing if the next depth interval. The process is repeated at multiple
desired. The tool string is then removed and decontaminated depths for groundwater profiling and multi-level slug testing.
for advancement at the next location or depth. The problem with multiple sampling events can be residual
6.2.3.2 Multiple Sampling Events—Dual tube systems allow groundwater in the dual tube casing from upper test zones. For
for continuous soil coring as the tool string is advanced. When water sampling this could cross contaminate deeper samples.
at the desired depth(s) a screen may be installed after the soil Sample quality must be evaluated by the user. If cross
core is removed (Fig. 6). Then the casing is retracted to deploy contamination is suspected, then it may be required to go back
the screen. This sequence may be repeated to conduct ground- and target intervals for discrete sealed screen samplers or just
water profiling. Alternately, the outer casing may be advanced consider data as screening level for detection of hot spots. In
to the initial sampling depth with an inner drive rod holding a unstable formations (heaving sands, etc.) it is necessary to add
D6001/D6001M − 20
FIG. 4 Drive Point Profiler and Profiler Showing Expendable Grout Tip Option (Solinst, (21))
FIG. 5 Dual Tube Groundwater Sampling Operation Modes—Operation as an Expendable Point Single Depth Sampler (23)
clean water to the outer casing as the inner rod and drive point additional purging may be advised to achieve stabilized water
or screen and riser pipe are removed to prevent formation quality parameters before sampling is performed at each
heave into the outer casing. This may slow progress and interval.
D6001/D6001M − 20
FIG. 6 Dual Tube Groundwater Sampling Operation Modes, Operating as a Dual Tube Combination Soil and Groundwater Sampler with
Profiling Capabilities. A solid drive point may be substituted for the sample tube during advancement to close off the cutting shoe if
no soil coring is needed (23)
6.2.4 Cone Penetrometer with Exposed Sampling Ports— 6.2.5.1 Temporary wells or T wells—The practice of insert-
Another form of an exposed-screen sampler has been incorpo- ing exposed screen slotted PVC pipe in an open hole after
rated into cone penetrometer bodies (24). The cone penetrom- drilling (Guide D6286/D6286M) or direct push testing is
eters have sample chambers with measurement devices such as sometimes performed on worksites in dry holes and are left
temperature and conductivity. Some cone penetrometers have overnight for estimat
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6001 − 05 (Reapproved 2012) D6001/D6001M − 20
Standard Guide for
Direct-Push Groundwater Sampling for Environmental Site
Characterization
This standard is issued under the fixed designation D6001;D6001/D6001M; the number immediately following the designation indicates
the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Scope*
1.1 This guide covers a review of methods for sampling groundwater at discrete points or in increments by insertion of
groundwater sampling devices by static force or impactusing Direct Push Methods (D6286/D6286M without drilling and removal
of cuttings. , see 3.3.2). By directly pushing the sampler, the soil is displaced and helps to form an annular seal above the sampling
zone. Direct-push water sampling can be one time, or multiple sampling events. Methods for obtaining water samples for water
quality analysis and detection of contaminants are presented.Knowledge of site specific geology and hydrogeologic conditions is
necessary to successfully obtain groundwater samples with these devices.
1.2 Direct-push methods of water sampling are used for groundwater quality and geohydrologic studies. Water quality and
permeability may vary at different depths below the surface depending on geohydrologic conditions. Incremental sampling or
sampling at discrete depths is used to determine the distribution of contaminants and to more completely characterize
geohydrologic environments. These investigationsexplorations are frequently requiredadvised in characterization of hazardous and
toxic waste sites.sites and for geohydrologic studies.
1.3 This guide covers several types of groundwater samplers; sealed screen samplers, profiling samplers, dual tube sampling
systems, and simple exposed screen samplers. In general, sealed screen samplers driven to discrete depth provide the highest
quality water samples. Profiling samplers using an exposed screen(s) which are purged between sampling events allow for more
rapid sample collection at multiple depths. Simple exposed screen samplers driven to a test zone with no purging prior to sampling
may result in more questionable water quality if exposed to upper contaminated zones, and in that case, would be considered
screening devices.
1.4 Methods for obtaining groundwater samples for water quality analysis and detection of contaminants are presented. These
methods include use of related standards such as; selection of purging and sampling devices (Guide D6452 and D6634/D6634M),
sampling methods (Guide D4448 and D6771) and sampling preparation and handling (Guides D5903, D6089, D6517,
D6564/D6564M, and D6911).
1.5 Direct-push methods can provide accurate information on the distribution of water quality if provisions are made to ensure
that cross-contamination or linkage between water bearing strata are not made. Discrete point sampling with a sealed (protected)
screen sampler, combined with on-site analysis of water samples, can provide the most accurate depiction of water quality
conditions at the time of sampling. Direct-push water sampling with exposed-screen sampling When appropriately installed and
developed many of these devices may be useful and are considered as screening tools depending on precautions taken during
This guide is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.21 on Groundwater and Vadose
Zone Investigations.
Current edition approved Jan. 15, 2012Sept. 1, 2020. Published December 2012November 2020. Originally approved in 1996. Last previous edition approved in 20052012
as D6001 – 05.D6001 – 05(2012). DOI: 10.1520/D6001-05R12.10.1520/D6001_D6001M-20.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6001/D6001M − 20
testing. Exposed screen samplers may require development or purging depending on sampling and quality assurance plans. Results
from direct-push investigations can be used to guide placement used to perform pneumatic slug testing (Practice D7242/D7242Mof
permanent groundwater monitoring wells and direct remediation efforts. Multiple sampling events ) to quantitatively evaluate
formation hydraulic conductivity over discrete intervals of unconsolidated formations. These slug tests provide reliable
determinations of hydraulic conductivity and can be performed to depict conditions over time. Use of double tube tooling, where
the outer push tube seals the hole, prevents the sampling tools from coming in contact with the formation, except at the sampling
point.after water quality sampling is completed.
1.4 Field test methods described in this guide include installation of temporary well points, and insertion of water samplers using
a variety of insertion methods. Insertion methods include: (1) soil probing using combinations of impact, percussion, or vibratory
driving with or without additions of smooth static force; (2) smooth static force from the surface using hydraulic cone penetrometer
(Guide D6067) or drilling equipment (Guide D6286), and incremental drilling combined with direct-push water sampling events.
Under typical incremental drilling operations, samplers are advanced with assistance of drilling equipment by smooth hydraulic
push, or mechanical impacts from hammers or other vibratory equipment. Direct-push water sampling maybe combined with other
sampling methods (Guide D6169) in drilled holes. Methods for borehole abandonment by grouting are also addressed.
1.6 Direct-push water sampling is limited to soils unconsolidated formations that can be penetrated with available equipment. In
strong soils damage may result during insertion of the sampler from rod bending or assembly buckling. Penetration may be limited,
or damage to samplers or rods can occur in certain ground conditions, some of which are discussed in 5.65.7. Information in this
procedure is limited Drilling equipment such as sonic drilling (Practice D6914/D6914M) or rotary drilling (Guide D6286/
D6286Mto sampling of saturated soils in perched or saturated groundwater conditions. ) can be used to advance holes past
formations difficult to penetrate using typical Direct Push equipment. Some soil formations do not yield water in a timely fashion
for direct-push sampling. In the case of unyielding formations, direct-push soil sampling can be performed (Guide D6282D6282/
D6282M).
1.7 Direct push water sampling with one-time sealed screen samplers can also be performed using cone penetrometer equipment
(Guide D6067/D6067M).
1.8 This guide does not address installation of permanent water sampling systems such as those presented in Practice
D5092D5092/D5092M. Direct-push monitoring wells for long term monitoring are addressed in Guide D6724D6724/D6724M and
Practice D6725D6725/D6725M.
1.9 Units—The values stated in either SI units or inch-pound units [presented in brackets] are to be regarded separately as
standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of
the other. Combining values from the two systems may result in nonconformance with the standard. Reporting of test results in
units other than SI shall not be regarded as nonconformance with this standard.
1.10 Direct-push water sampling for geoenvironmental exploration will often involve safety planning,All observed and calculated
values shall conform to the guidelines for significant digits and rounding established in Practice D6026administration, and
documentation., unless superseded by this standard.
1.11 This guidestandard does not purport to address all aspects of exploration and site safety. of the safety concerns, if any,
associated with its use. It is the responsibility of the user of this guidestandard to establish appropriate safety safety, health, and
healthenvironmental practices and determine the applicability of regulatory limitations before itsprior to use.
1.12 This guide offers an organized collection of information or a series of options and does not recommend a specific course of
action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not
all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the
standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied
without consideration of a project’s many unique aspects. The word “Standard” in the title of this document means only that the
document has been approved through the ASTM consensus process.
1.13 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
D6001/D6001M − 20
2. Referenced Documents
2.1 ASTM Standards:
D653 Terminology Relating to Soil, Rock, and Contained Fluids
D1586/D1586M Test Method for Standard Penetration Test (SPT) and Split-Barrel Sampling of Soils
D2488 Practice for Description and Identification of Soils (Visual-Manual Procedures)
D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in
Engineering Design and Construction
D4448 Guide for Sampling Ground-Water Monitoring Wells
D4750 Test Method for Determining Subsurface Liquid Levels in a Borehole or Monitoring Well (Observation Well)
(Withdrawn 2010)
D5088 Practice for Decontamination of Field Equipment Used at Waste Sites
D5092D5092/D5092M Practice for Design and Installation of Groundwater Monitoring Wells
D5254 Practice for Minimum Set of Data Elements to Identify a Groundwater Site
D5314 Guide for Soil Gas Monitoring in the Vadose Zone (Withdrawn 2015)
D5434 Guide for Field Logging of Subsurface Explorations of Soil and Rock
D5474 Guide for Selection of Data Elements for Groundwater Investigations
D5521D5521/D5521M Guide for Development of Groundwater Monitoring Wells in Granular Aquifers
D5730 Guide for Site Characterization for Environmental Purposes With Emphasis on Soil, Rock, the Vadose Zone and
Groundwater (Withdrawn 2013)
D5778 Test Method for Electronic Friction Cone and Piezocone Penetration Testing of Soils
D5903 Guide for Planning and Preparing for a Groundwater Sampling Event
D6026 Practice for Using Significant Digits in Geotechnical Data
D6067D6067/D6067M Practice for Using the Electronic Piezocone Penetrometer Tests for Environmental Site Characterization
and Estimation of Hydraulic Conductivity
D6089 Guide for Documenting a Groundwater Sampling Event
D6187 Practice for Cone Penetrometer Technology Characterization of Petroleum Contaminated Sites with Nitrogen
Laser-Induced Fluorescence (Withdrawn 2019)
D6235 Practice for Expedited Site Characterization of Vadose Zone and Groundwater Contamination at Hazardous Waste
Contaminated Sites
D6452 Guide for Purging Methods for Wells Used for Ground Water Quality Investigations
D6517 Guide for Field Preservation of Ground Water Samples
D6564D6564/D6564M Guide for Field Filtration of Groundwater Samples
D6634D6634/D6634M Guide for Selection of Purging and Sampling Devices for Groundwater Monitoring Wells
D6724D6724/D6724M Guide for Installation of Direct Push Groundwater Monitoring Wells
D6725D6725/D6725M Practice for Direct Push Installation of Prepacked Screen Monitoring Wells in Unconsolidated Aquifers
D6771 Practice for Low-Flow Purging and Sampling for Wells and Devices Used for Ground-Water Quality Investigations
D6911 Guide for Packaging and Shipping Environmental Samples for Laboratory Analysis
D7242/D7242M Practice for Field Pneumatic Slug (Instantaneous Change in Head) Tests to Determine Hydraulic Properties of
Aquifers with Direct Push Groundwater Samplers
D7352 Practice for Volatile Contaminant Logging Using a Membrane Interface Probe (MIP) in Unconsolidated Formations with
Direct Push Methods
D8037/D8037M Practice for Direct Push Hydraulic Logging for Profiling Variations of Permeability in Soils
2.2 Drilling Methods:
D5781D5781/D5781M Guide for the Use of Dual-Wall Reverse-Circulation Drilling for Geoenvironmental Exploration and the
Installation of Subsurface Water-Quality Water Quality Monitoring Devices
D5782 Guide for the Use of Direct Air-Rotary Drilling for Geoenvironmental Exploration and the Installation of Subsurface
Water-Quality Monitoring Devices
D5783 Guide for the Use of Direct Rotary Drilling with Water-Based Drilling Fluid for Geoenvironmental Exploration and the
Installation of Subsurface Water-Quality Monitoring Devices
D5784D5784/D5784M Guide for the Use of Hollow-Stem Augers for Geoenvironmental Exploration and the Installation of
Subsurface Water-Quality Water Quality Monitoring Devices
D5875D5875/D5875M Guide for the Use of Cable-Tool Drilling and Sampling Methods for Geoenvironmental Exploration-
sExploration and Installation of Subsurface Water-Quality Water Quality Monitoring Devices
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
D6001/D6001M − 20
D5876D5876/D5876M Guide for the Use of Direct Rotary Wireline Casing Advancement Drilling Methods for Geoenviron-
mental Exploration and the Installation of Subsurface Water-Quality Monitoring Devices
D6286D6286/D6286M Guide to the for Selection of Drilling and Direct Push Methods for Geotechnical and Environmental
Subsurface Site Characterization
D6914/D6914M Practice for Sonic Drilling for Site Characterization and the Installation of Subsurface Monitoring Devices
2.3 Soil Sampling:
D4700D6282/D6282M Guide for Direct Push Soil Sampling from the Vadose Zonefor Environmental Site Characterizations
D6169 Guide to the Selection of Soil and Rock Sampling Devices Used With Drilling Rigs for Environmental Investigations
D6282 Guide for Direct-Push Soil Sampling for Environmental Site Characterization
3. Terminology
3.1 Terminology used within this guide is in accordance with Terminology D653 with the addition of the following:Definitions:
3.1.1 For definitions of common technical terms in this standard, refer to Terminology D653.
3.2 Definitions in AccordanceThe definitions below are in Terminology D653with , and as adopted from Practice D5092D5092/
D5092M: on installation of monitoring wells.
3.2.1 bailer—bailer, n—in wells, a hollow tubular receptacle used to facilitate removal of fluid from a well or borehole.
3.2.2 borehole—borehole, n—a circularin drilling, an open or uncased subsurface hole hole, generally circular in plain view,
created by drilling.
3.2.2.1 Discussion—
Normally, a borehole is advanced using an auger, a drill, or casing with or without drilling fluid, but for this standard it is made
using direct push methods (3.3.2).
3.2.3 casing—casing, n—in drilling, pipe, finished in sections with either threaded connections or beveled edges to be field
welded, which is installed temporarily or permanently to counteract caving, to advance the borehole, or to isolate the intervalzone
being monitored, or combination thereof.
3.2.4 caving; sloughing—sloughing, v—in drilling, the inflow of unconsolidated material into a borehole that occurs when the
borehole walls lose their cohesive strength.
3.2.5 centralizer—centralizer, n—in drilling, a device that helpsassists in the centering of a casing or riser within a borehole or
another casing.
3.2.6 jetting—when applied as a drilling method, water is forced down through the drill rods or riser pipe and out through the end
openings. The jetting water then transports the generated cuttings to the ground surface in the annulus of the drill rods or casing
and the borehole. The term jetting may also refer to a well development technique.
3.2.6 PTFE tape—tape, n—in drilling, joint sealing tape composed of polytetrafluorethylene.
3.2.6.1 Discussion—
For sampling of (PFAS, 3.3.11), PTFE tape may not be used in well assembly due to the potential for cross contamination.
3.2.7 slot, n—in well screen opening, slot openings have been designated by numbers which correspond to the width of the
openings in thousandths of an inch.
3.2.7.1 Discussion—
A No. 10 slot screen, for example, is an opening of 0.25 mm [0.010 in.].
3.2.8 well screen—screen, n—in wells, a filtering device used to retain the primary or natural filter pack; usually a cylindrical pipe
with openings of uniform width, orientation, and spacing.
3.3 Definitions of Terms Specific to This Standard:
3.3.1 assembly length—length, n—length of sampler body and riser pipes.
D6001/D6001M − 20
3.3.2 bentonite—direct-push (DP) method, v—the common name for drilling fluid additives and well construction products
consisting mostly of naturally occurring sodium montmorillonite. Some bentonite products have chemical additives that may affect
water quality analyses (seea subsurface exploration method by which drive rod, casing tube, sampling, and logging devices are
pushed, driven, or vibrated into soils or unconsolidated formations to be sampled or logged without rotary drilling and removal
of 9.3.3).cuttings.
3.3.2.1 Discussion—
For the purposes of this guide, a subsurface exploration method that uses hand-held percussion driving devices, or hydraulic
percussion, quasi static push, or vibratory drive systems that are mounted to a truck, van, all-terrain vehicle, trailer, skid, or drill
rig.
3.3.3 direct-push sampling—groundwater sampler, n—sampling devices that are directly inserted into the soil to be sampled
without drilling or borehole excavation.a sampler specially designed for use with direct push methods to collect groundwater from
relatively pervious soils (aquifers).
3.3.4 drill hole—exposed screen sampler, n—in drilling, a cylindrical hole advanced into the subsurface by mechanical means;
also, known as borehole or boring.sampler with an exposed screen driven to the sampling depth that may be exposed to cross
contamination prior to the sampling.
3.3.5 effectiveexposed screen length—length, n—the length of a screen open or exposed to water bearing strata.
3.3.5.1 Discussion—
In some DP groundwater sampling devices only a portion of the screen may be exposed to the formation to target a discrete zone
for sampling.
3.3.6 effective seal length—length, n—the length of soil above the wellsampler screen that is in intimate contact with the riser pipe
and prevents connection of the well screen with groundwater from otheroverlying zones.
3.3.7 grab sampling—groundwater sampling, v—in groundwater, the process of rapidly collecting a sample of fluid exposed to
atmospheric pressure through the riser pipe with bailers or other methods that may include pumping; also known as batch
sampling.water sample with minimal purging or development using simple equipment like bailers or pumps at a specific time,
location, and depth.
3.3.7.1 Discussion—
Grab sampling is a rapid sampling event with little or no purging or development of the test zone, often using simple devices like
a bailer or inertial pumps.
3.3.8 incremental drilling and sampling—sampling, n—in drilling, insertion method where rotary drilling and sampling events are
alternated for incremental sampling. Incremental drilling is often needed to penetrate harder or deeper formations.
3.3.9 groundwater profiling, v—the method of advancing a groundwater sampling device incrementally and collecting discrete
samples of groundwater at each depth interval.
3.3.10 percussion driving—driving, v—insertion method where rapid hammer impacts are performed to insert the sampling device.
The device and the percussion is normally accompanied with application of static down force.
3.3.11 PFAS, n—polyfluorinated alkyl substances: includes PFOS (perfluorooctane sulfonate) and PFOA (perfluorooctanoate acid)
that have very low detection levels, in parts per trillion for combined concentration in drinking water.
3.3.11.1 Discussion—
PFAS includes hundreds of poly fluorinated compounds, many of which are components of aqueous fire-fighting foams (AFFF)
previously used at military and commercial airports. PFAS compounds have been used in many industrial and commercial
products. Polytetrafluorethylene containing materials and products are excluded from use when PFAS sampling is conducted.
3.3.12 push depth—depth, n—the depth below a ground surface datum that the end or tip of the direct-push water sampling device
is inserted.
D6001/D6001M − 20
3.3.13 sampler screen, n—a well screen mesh or slot system designed to filter coarse particles from the sampling test zone or ports
of the direct push groundwater sampler.
3.3.14 sealed screen sampler, n—a groundwater sampler where the sampler screen is sealed until the sampling depth is reached
thus preventing exposure to groundwater from previous depths and accurate evaluation of water quality at the point of sampling.
3.3.15 unconsolidated geologic materials, n—in groundwater, geology, or hydrogeology, a loosely aggregated solid (particulate)
material of geologic origin (soil, sediments, etc.).
3.3.15.1 Discussion—
Groundwater hydrologists, and geologists, use the terms unconsolidated formations, deposits, sediments, units, materials, etc., to
refer to the general term “soil” including other soils (alluvium, glacial till, etc.) as defined in D653. These terms are often found
in groundwater standards applied to aquifers. Unconsolidated materials are non-lithified, typically lacking cementation of
individual particles (clay, silt sand, gravel, etc.). The term “unconsolidated” should not be confused with geotechnical terms of the
degree of soil consolidation (over, normally, under-consolidated) as defined in D653.
3.4 Acronyms:
3.4.1 DP—Direct Push methods (3.3.2).
4. Summary of Guide
4.1 Direct-push water sampling groundwater sampling may be performed using different procedures depending on the device
design and purpose of the investigation. One single-tube procedure consists of pushing a sealed protected well screen sampler to
a known depth, opening the wellsampler screen over a knownspecified interval, and sampling watergroundwater from the interval.
A well point with an exposed screen can also be pushed with understanding of potential cross-contamination effects and purging
requirements considered. A sampler The single tube sealed screen method will provide the highest integrity water quality samples.
A sampler, often with constant outside diameter is inserted directly into the soil by hydraulic jacking or hammering percussion
hammering and/or static push until sufficient riser pipe is seated into the soil to ensure a seal. Protected well Sealed screens can
be exposed by retraction of riser pipes. While the riser is seated in the soil, water samples can be taken, and water injection or
pressure measurements may be performed. Following adequate development many of these devices can be slug tested using
pneumatic methods (Practice D7242/D7242M) to obtain data about formation hydraulic conductivity.
4.2 Profiling samplers allow the operator to collect samples of groundwater at multiple, increasing depths as the tool is
incrementally advanced. These exposed screen samplers may be advanced as water is injected into the formation through the
screen(s) or port(s). The injection pressure and flow rate of the water may be monitored to evaluate formation permeability as some
devices are advanced. These devices are subject to cross contamination and “drag down” of contaminants as the exposed screens
are advanced to increasing depths. Injection of clean water out of the screen(s) as the tools are advanced to increasing depths may
help reduce the drag down effect.
4.3 Dual-tube groundwater systems provide for the insertion and removal of fresh screens at multiple depths as the outer casing
is incrementally advanced to depth. The system can be used for one-time sampling events as a sealed screen sampler. However,
a one-time sampling event when used for multiple vents and after soils sampling the water from previous sampling intervals left
in the outer casing as the exposed screen tool string is advanced may lead to cross contamination. In saturated sands formation
heave may be difficult to control in the dual tube sand formations systems without the addition of excessive amounts of water to
control the hydraulic head. Dual-tube systems may be slug tested (Practice D7242/D7242M) to determine the hydraulic
conductivity of the screened formation, following adequate development.
4.4 Development of the screened formation and sampling groundwater may be performed using a variety of tools and methods
depending on the design of the sampling device (Guide D5521/D5521M). Development is most often performed with an inertial
check valve in the small diameter piezometers having an open annulus to the surface. Occasionally, a mini-surge block or similar
device may be used for development of these types of tools. Sampling of the open annulus tools may be performed with devices
such as a mini-bailer, inertial pump, peristaltic pump or small diameter bladder pump (Guide D6634/D6634M). Review project
data quality objectives to determine the appropriate sampling device and method. DP groundwater profiling devices often have
tubing, integrated pumps and/or trunk lines in the annulus of the drive casing. This precludes performance of typical formation
development procedures, other than pumping. The profiling devices are often purged and sampled with a peristaltic pump or
integrated downhole pump. The integrated pumps may be of various design.
D6001/D6001M − 20
5. Significance and Use
5.1 Direct-push water sampling is an economical methodgroundwater sampling and profiling are economical methods for
obtaining discrete interval groundwater samples quality samples in many soils and unconsolidated formations without the expense
of permanent monitoring well installation (1-610). This guide Many of these devices can be used to profile potential groundwater
contamination quality or contamination and/or hydraulic conductivity with depth by performing repetitive sampling events.
Direct-push waterand testing events. DP groundwater sampling is often used in expedited site characterization (Practice D6235)
and as a means to accomplish high resolution site characterization (HRSC) (11, 12). Soils The formation to be sampled mustshould
be sufficiently permeable to allow filling of the sampler in a relatively short time. The zone to be sampled and/or slug tested can
be isolated by matching wellsampler screen length to obtain discrete samples of thin aquifers. saturated, permeable layers. Use of
these sampling and hydraulic testing techniques will result in more detailed characterization of sites containing multiple aquifers.
By inserting a protected sampling screen in direct contact with soil and with watertight risers, initial well The field conditions,
sampler design and data quality objectives should be reviewed to determine if development (Guide D5521D5521/D5521M) and
purging of wells (Guideof the screened D6452) may not be required for the first sampling event. formation is appropriate. The
samplers do not have a filter pack designed to retain fines like conventional wells, but only a slotted screen or wire-mesh covered
ports. So, obtaining low turbidity samples may be difficult or even impossible in formations with a significant proportion of
fine-grained materials. With most systems turbidity will always be high so consult Guide D6564/D6564M if field filtration of
samples is required. Discrete water sampling, combined with knowledge of location and thickness of target aquifers, may better
define conditions in thin multiple aquifers than monitoring wells with long screened intervals that can intersect and allow for
intercommunication of multiple aquifers (4, 6,7, 11-158,9). Direct-pushDP sampling performed without knowledge of the location
and thickness of target aquifers can result in sampling of the wrong aquifer or penetration through confining beds. Results from
DP explorations can be used to develop conceptual site models, guide placement of permanent groundwater monitoring wells, and
direct remediation efforts. These devices are often used under dynamic work plans (11, 16) to complete site characterizations in
a single mobilization. However, multiple sampling events can be performed to depict conditions over time or refine earlier work
if needed.
5.2 Targeting Aquifer Sample Test Zones for Accurate Sampling—As with any investigation it is important to phase the
investigation such that target intervals for groundwater sampling are accurately located. For sites that allow surface push of the
sampling device, discrete water sampling is often performed in conjunction with the cone penetration test (Test Method
D6067D6067/D6067M) (4-68),, 13, 14) or continuous soil sampling (Guide D6282/D6282M) which is often used for stratigraphic
mapping of aquifers,aquifers and to delineate high-permeability zones. zones for sampling. Alternately, resistivity logging, or
injection logging (Practice D8037/D8037M) may be used to assess formation permeability and lithology prior to the groundwater
sampling or profiling activities to guide selection of sampling intervals (10, 15, 17). In such cases, direct-pushDP water sampling
is normally performed close to cone previous test holes. In complex alluvial environments,depositional environments (12), thin
aquifers may vary in continuity such that water sampling devices may not intersect the same layer at equivalent depths as
companion cone penetrometer holes.HPT, cone penetrometer, or electrical resistivity profiling soundings.
5.2.1 When volatile organic contaminants (VOC) such as trichloroethylene (TCE) or benzene are present in the subsurface,
logging with the membrane interface probe (MIP) (Practice D7352) may be performed prior to groundwater sampling. MIP logs
identify where significant concentrations of many VOCs are present and may be used to guide selection of groundwater sampling
locations, depths and intervals (17). When petroleum fuels are present in the subsurface laser induced fluorescence (LIF) (Practice
D6187) or the Optical Imaging Profiler (OIP) (18) may be used to identify where significant petroleum contamination is present
to assist in guiding selection of sample locations and depths.
5.3 Slug tests can be performed with several of the DP groundwater samplers (D7242/D7242M) to determine hydraulic
conductivity over discrete intervals. Development of the screened interval should be conducted to assure that formation flow into
and out of the device is representative of natural formation conditions. Development with a simple inertial pump to surge and purge
the formation is often adequate. Other methods for development (D5521/D5521M) may be advised depending on field conditions
and data quality objectives.
5.4 Water sampling chambers may be sealed to maintain in situ pressures and to allow for pressure measurements and permeability
testing (Practice D7242/D7242M) (6, 813, 1119). Sealing of samples under pressure may reduce the possible volatilization of some
organic compounds. Field comparisons may be used to evaluate any systematic errors in sampling equipments and methods.
Comparison studies may include the need for pressurizing samples, or the use of vacuum to extract fluids more rapidly from low
hydraulic conductivity soils (8.1.5.38.2.3.1). (2)).
The boldface numbers in parentheses refer to a list of references at the end of this guide.standard.
D6001/D6001M − 20
5.5 DP groundwater profiling tools (7, 8, 10, 20, 21) allow the investigator to sample groundwater at multiple depths during
incremental advancement of the device. Clean water is injected through the screen(s) or port(s) of these tools to keep the screens
open and rinsed as advancement proceeds. Concerns for cross contamination and contaminant drag down must be considered.
Some tools have an inline pressure transducer either above grade or down hole to monitor pressure required to inject water into
the formation during advancement. The pressure injection log may be used to guide selection of permeable zones for sampling.
When the injection flow rate is also measured, estimates of formation permeability may be calculated.
5.6 Degradation of water samples during handling and transport can be reduced if discrete water sampling events with
protectedsealed screen samplers are combined with real time field analysis of potential contaminants. In limited studies, researchers
have found that the combination of discrete protectedsealed screen sampling with onsite field analytical testing provide accurate
data of aquifer water quality conditions at the time of testing (4, 6). Direct-pushDP water sampling with exposed screen sampling
devices, which may require development or purging, are considered as screening tools depending on precautions that are taken
during testing.
5.5 A well screen may be pushed into undisturbed soils at the base of a drill hole and backfilled to make permanent installed
monitoring wells. Procedures to complete direct-push wells as permanent installations are given in Practice D6725 and Guide
D6724.
5.7 In difficult driving conditions, penetrating to the requireddesired depth to ensure make sure of sealing of the sampler well
screen may not be possible. If the well screen cannot be inserted into the soilformation with an adequate seal, the water-sampling
event would require sealing in accordance with Practice D5092D5092/D5092M to isolate the required aquifer. Selection of the
appropriate equipment and methods to reach required depth at the site of concern should be made in consultation with experienced
operators or manufacturers. If there is no information as to the subsurface conditions, initial explorations consisting of
penetration-resistance tests, such as Test Method D6067D6067/D6067M, or actual direct-push testing resistivity profiling, or DP
logging with the injection logging system (Practice D8037/D8037M) to perform trials can be performed to select the appropriate
testing system.
5.7.1 Typical penetration depths for a specific equipment configuration depend on many variables. Some of the variables are the
driving system, the diameter of the sampler and riser pipes, and the resistance of the materials.
5.7.2 Certain subsurface conditions may prevent sampler insertion. Penetration is not possible in hard rock and usuallysometimes
not possible in softer rocks such as claystones and shales. Coarse particles such as gravels, cobbles, and boulders may be difficult
to penetrate or cause damage to the sampler or riser pipes. Cemented soil zones may be difficult to penetrate depending on the
strength and thickness of the layers. If layers are present that prevent direct-pushDP from the surface, thethen rotary or percussion
drilling methods (Guide D6286D6286/D6286M) can be employed to advance a boring through impeding layers to reach testing
zones.
5.7.3 Driving systems are generally selected based on required testing depths and the materials to be penetrated. For systems using
primarily static reaction force to insert the sampler, depth will be limited by the reaction weight of the equipment or anchoring
stability and penetration resistance of the material. The ability to pull back the rod string is also a consideration. Impact or
percussion soil probing has an advantage of reducing the reaction weight required for penetration. Penetration capability in clays
may be increased by reducing rod friction by enlarging tips or friction reducers. However, over reaming of the hole may increase
the possibility of rod buckling and may allow for communication of differing groundwater tables. Hand-held equipment is
generally used on very shallow investigations,explorations, typically less than 5-m 5 m [15 ft] depth, but depths on the order of
10 m [30 ft] have been reached in very soft lacustrine clays. Intermediate size driving systems, such as small truck-mounted
hydraulic-powered push and impact drivers, typically work within depth ranges from 5 to 30 m. m [20 to 100 ft]. Larger DP
machines may be capable of reaching 60 m [200 ft] depending on subsurface conditions. Heavy static-push cone penetrometer
vehicles, such as 20-ton 20 ton trucks, typically work within depth ranges from 15 to 45 m, m [50 to 150 ft], and also reach depth
ranges on the order of 10100 m [300 ft] in soft ground conditions. Drilling methods (Guide D6286Guide D6286/D6286M) using
drilling and incremental sampling are frequently used in all depth ranges and can be used to reach depths on the order of 103 m.
shows depth ranges of other drilling equipment to attain greater depths.
NOTE 1—Users and manufacturers cannot agree on depth ranges for different soil types. Users should consult with experienced producers and
manufacturers to determine depth capability for their site conditions.
NOTE 1—Users and manufacturers cannot agree on depth ranges for different soil types. Users should consult with experienced local producers and
D6001/D6001M − 20
manufacturers to determine depth capability for their specific site conditions.
5.8 Combining multiple-sampling events in a single-sample chamber (profiling) without decontamination (Practices(Practice
D5088) is generally unacceptable.discouraged. In this application, purging of the screen or sampling chamber should be performed
to ensure make sure of isolation of the sampling event. Purging should be performed by removing several volumes of fluid until
new chemical properties have been stabilized or elements are flushed with fluid of known chemistry. Purging requirements may
depend upon the materials used in the sampler and the sampler design (Guide D6634D6634/D6634M). Rinsate samples may be
collected and analyzed to assess concerns with carryover of contaminants from overlying zones that are heavily contaminated.
Monitoring water quality parameters (pH, specific conductance, dissolved oxygen, oxidation-reduction potential, etc.) to stability
is often used to document when representative water is being purged from a sampling interval (Practice D6771).
5.9 Bottom-up profiling by driving a DP groundwater sampler to the base of the formation and retracting incrementally, while the
screen is exposed, for sampling at decreasing depths should be avoided as this may lead to cross contamination and inaccurate
contaminant distribution information. Slug tests should not be performed by bottom-up profiling as there is poor or no control on
the length of formation being tested under these conditions.
5.10 Screens designed and deployed in dual tube use are generally designed for use inside the dual tubing and overdriving the
screen past the casing can damage the sampler screen and subsequent exposed screen samples would be subject to cross
contamination. Use equipment according to manufactures instructions.
NOTE 2—The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the
equipment and facilities used. Practitioners that meet the criteria of Practice D3740 are generally considered capable of competent and objective
testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable
results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.
Practice D3740 was developed for agencies engaged in the testing and/or inspection of soils and rock. As such, it is not totally applicable to agencies
performing this field practice. However, users of this practice should recognize that the framework of Practice D3740 is appropriate for evaluating the
quality of an agency performing this practice. Currently there is no known qualifying national authority that inspects agencies that perform this practice.
6. Apparatus
6.1 General—A direct-push sampling system consists of a tip; well screen; chambers, if present; and riser pipesdrive rods (casing
and/or riser pipes) extending to the surface. Direct-pushDP water sampling equipment can be grouped into two classes, either with
a sealed protected screen or exposed screen (see screen. 6.2). There are also two types of drive systems, single tube and double
dual (double) tube (see 6.46.2.3).
6.2 Sampler Types—Samplers with protected or sealed screens depend on the sealseals to avoid exposure of the sampling interval
to chamber or screen to contaminated soil or water from other layers. They layers during advancement. Seals also should be
maintained at each rod joint to prevent infiltration of water or fines from intervals above the desired sample interval where o-rings
or plumbers’ tape may be used. These devices can be considered as accurate point-source detectors. They Single-tube sealed screen
devices are normally recovered and decontaminated between sampling events. Exposed-screen samplers may require purging and
development and as such In dual-tube systems the screen may be installed after the outer casing is advanced to the desired sampling
depth acting as a sealed screen sampler for one-time sampling events. If the dual tube is advanced in a soil sampling mode, and
then a water sampler is taken, the sampler screen is exposed to water in the casing. Exposed-screen samplers driven from the
surface are subject to contaminant drag down and may require additional purging and development. Exposed screen samplers in
these modes are considered as screening devices for profiling relative degrees of contamination. Exposed Screen Profiling samplers
used for groundwater profiling inject clean water during incremental advancement to minimize contaminant drag down and
carryover and can provide accurate point source water quality sampling.
6.2.1 Single-Tube Sealed-Screen Samplers—An example is shown in Fig. 1(22). This simple arrangement allows for grab sampling
through the riser pipe with minimal purging or development if there is no leakage at the screen seals and riser pipe joints. If desired,
development of these devices may be conducted prior to sampling. Development of the screened intervals is required before slug
testing is performed (D7242/D7242M). Fig. 2 shows a schematic of a DP water sampler with a sealed screen and with the ability
to work in the grab sampling mode or by allowing water to enter a sample chamber in the sampler body (5). Most simple sample
chambers allow for flow through the chamber. When a flow through chambered sampler is opened, it is possible that the
groundwater from the test interval can fill into the rods above the chamber. In those cases, it may be advisable to add water of
known chemistry into the rods prior to opening the screen. Some sealed-screen samplers have sample chambers designed to reduce
volume and pressure changes in the sample to avoid possible loss of volatile compounds (6, 13, 19). The need for pressurization
is dependent on the requirements of the exploration program and should be evaluated by comparison studies in the field with
simpler systems allowing the sample to equalize at atmospheric pressure. There are different approaches to pressurizing the sample
D6001/D6001M − 20
The assembled Sampler is Extension rods are used to hold The tubing check valve Abandonment grout-
driven to the desired sampling the screen in position as the Cas- can be used to sample ing can be conducted
depth using standard rods. ing Puller Assembly is used to groundwater. to meet ASTM re-
retract the
...