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