【国外标准】 Standard Guide for the Selection of Purging and Sampling Devices for Groundwater Monitoring Wells (Withdrawn 2023)

5.1 Appropriate purging and sampling equipment must be used to make sure that samples collected from monitoring wells represent the groundwater chemistry of the desired water bearing zone.5.2 This guide is intended to be a common reference for purging and sampling devices. It can be applied to groundwater quality sampling from monitoring wells used for groundwater contamination evaluation, water supply characterization, and research.5.3 This guide includes a number of general guidance statements that are not directly related to the operating principles or characteristics of the equipment. These statements are given to assist the user in understanding the application of the equipment, which could ultimately affect the selection process.1.1 This guide describes the characteristics and operating principles of purging and sampling devices available for use in groundwater monitoring wells and provides criteria for selecting appropriate devices for specific applications. The selected device(s) should be capable of purging the well and providing valid representative samples of groundwater and included dissolved constituents. The scope does not include procedures for purging or collecting samples from monitoring wells, sampling devices for non-aqueous phase liquids, diffusion-type sampling devices or sampling from devices other than monitoring wells.1.2 This guide reviews many of the most commonly used devices for purging and sampling groundwater monitoring wells. The practitioner should ensure that the purging and sampling methods used, whether or not they are addressed in this guide, are adequate to satisfy the monitoring objectives at each site.1.3 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This guide 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 guide 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 the many unique aspects of a project. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.1.4 The values stated in either SI units or inch-pound units 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 non-conformance with the standard. Dimensions provided are typical.1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.