1. Scope

1.1 This guide covers a review of methods for sampling groundwater at discrete points or in increments by insertion of sampling devices by static force or impact without drilling and removal of cuttings. 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.

1.2 Direct-push methods of water sampling are used for groundwater quality studies. Water quality 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 investigations are frequently required in characterization of hazardous and toxic waste sites.

1.3 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 devices may be useful and are considered as screening tools depending on precautions taken during 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 of permanent groundwater monitoring wells and direct remediation efforts. Multiple sampling events 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.

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 ), 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 ) in drilled holes. Methods for borehole abandonment by grouting are also addressed.

1.5 Direct-push water sampling is limited to soils 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 5.6. Information in this procedure is limited to sampling of saturated soils in perched or saturated groundwater conditions. 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 ).

1.6 This guide does not address installation of permanent water sampling systems such as those presented in Practice D5092 . Direct-push monitoring wells for long term monitoring are addressed in Guide D6724 and Practice D6725 .

1.7 Direct-push water sampling for geoenvironmental exploration will often involve safety planning, administration, and documentation.

1.8 This guide does not purport to address all aspects of exploration and site safety. It is the responsibility of the user of this guide to establish appropriate safety and health practices and determine the applicability of regulatory limitations before its use.

1.9 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.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D653 Terminology Relating to Soil, Rock, and Contained Fluids

D2488 Practice for Description and Identification of Soils (Visual-Manual Procedure)

D4448 Guide for Sampling Ground-Water Monitoring Wells

D4750 Test Method for Determining Subsurface Liquid Levels in a Borehole or Monitoring Well (Observation Well)

D5088 Practice for Decontamination of Field Equipment Used at Waste Sites

D5092 Practice for Design and Installation of Ground Water Monitoring Wells

D5254 Practice for Minimum Set of Data Elements to Identify a Ground-Water Site

D5314 Guide for Soil Gas Monitoring in the Vadose Zone

D5434 Guide for Field Logging of Subsurface Explorations of Soil and Rock

D5474 Guide for Selection of Data Elements for Groundwater Investigations

D5521 Guide for Development of Ground-Water Monitoring Wells in Granular Aquifers

D5730 Guide for Site Characterization for Environmental Purposes With Emphasis on Soil, Rock, the Vadose Zone and Ground Water

D5778 Test Method for Electronic Friction Cone and Piezocone Penetration Testing of Soils

D5903 Guide for Planning and Preparing for a Groundwater Sampling Event

D6067 Practice for Using the Electronic Piezocone Penetrometer Tests for Environmental Site Characterization

D6089 Guide for Documenting a Ground-Water Sampling Event

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 Groundwater Samples

D6564 Guide for Field Filtration of Ground-Water Samples

D6634 Guide for the Selection of Purging and Sampling Devices for Ground-Water Monitoring Wells

D6724 Guide for Installation of Direct Push Groundwater Monitoring Wells

D6725 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

Keywords

direct-push; groundwater; groundwater sampling; site characterization; well point ;

ICS Code

ICS Number Code 13.060.10 (Water of natural resources)

DOI: 10.1520/D6001-05

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