E-School

Since regulatory programs mandating ground-water monitoring and sampling at a variety of sites first started in the 1970s, a number of different approaches for collecting ground-water samples from monitoring wells have been implemented. Some of the “conventional” purging and sampling practices first used in the 1970s (like well-volume purging and sampling and purging a well to dryness) continue to be implemented today, even though it has been repeatedly demonstrated through decades of research that these methods are rarely, if ever, capable of producing representative samples. This module discusses how these practices are implemented, and how these and other practices are applied to both high-yield wells and low-yield wells that tend to go dry during purging. Discussions are provided to document the limitations that research has found with these purging and sampling practices. If you are still purging 3 to 5 well volumes as a purging strategy or if you are still purging wells to dryness then returning in 24 hours to sample (or if you are overseeing projects where these techniques are being used), then this is a module you should not miss! Field videos are included within this module to explain the practices and procedures used in conventional purging and sampling.

Module ES–22 (Total Length: 51 minutes) Price: $159.00 Sign in to YOur E-School Account to Register

Conventional Purging and Sampling Practices for High-Yield and Low-Yield Wells – Well-Volume Purging; Purging to Stabilization of Water-Quality Indicators; Purging to Dryness, Then Sampling

Objectives of Conventional Purging
Discussion of ASTM Standards D 6452 on Purging Ground-Water Monitoring Wells and D 4448 on Sampling Ground-Water Monitoring Wells
Comparison of Conventional Strategies for Purging High-Yield Wells
Problems With Conventional Purging Methods for High-Yield Wells
Placement of Purging Devices Within the Water Column
Conventional and Improved Approaches to Sampling Low-Yield Wells

Total CEUs for Module ES-22: 1 CEU

Traditional ground-water sample collection methods, including well-volume purging and sampling and purging a well to dryness, are subject to significant sources of bias and error that commonly result in either over- or under-estimation of actual sample concentrations and poor precision and accuracy. It is thus exceedingly important to use more up-to-date methods, like low-flow purging and sampling and no-purge sampling, that have been demonstrated by many field research studies to produce higher quality samples so all stakeholders can have much higher confidence in sample analytical results. This series of two modules comprehensively covers the topics of low-flow purging and sampling and the newer methodology referred to as no-purge sampling, and explains why and how low-flow purging and sampling and no-purge sampling always produce dramatically improved and more consistent sampling results and significant cost savings. Field videos are included within these modules to help explain the practices and procedures required to implement low-flow purging and sampling and no-purge sampling. While you may opt to take just one of these modules, it is strongly recommended that you take both modules in the prescribed order if you want comprehensive coverage of the subject.

Module ES–23 (Total Length: 58 Minutes) Price: $159.00 Sign in to Your E-School Account to Register

Practices and Procedures for Low-Flow Purging and Sampling