One of the keys to successful remediation of a contaminated property is effective groundwater sampling. A new ASTM standard will aid groundwater samplers by taking a look at three types of passive samplers and their advantages, disadvantages and limitations.
The new standard is D7929, Guide for Selection of Passive Techniques for Sampling Groundwater Monitoring Wells. The three types of samplers discussed are:
- Passive grab samplers, used to collect a whole water sample from a discrete depth or interval within the well after a predetermined deployment period;
- Diffusion samplers, which rely on diffusion of analytes of interest through a membrane into distilled or deionized water contained inside the sampler; and
- Accumulation samplers, in which diffusion through a membrane and then sorption by sorbent media occurs to accumulate the analytes of interest within the sampler.
ASTM member Louise Parker, who recently retired from U.S. Army Cold Regions Research, notes that the new standard is very flexible.
“Because this technology has seen rapid development, we felt that it was important that this guide not be restrictive, but rather would allow application of new methods and devices as they are developed,” says Parker.
The standard was designed to provide a broad user audience with the resources they need to enhance their involvement in groundwater sampling. Regulators, samplers, technology developers and laboratory technicians will all find D7929 to be a helpful tool for their work.
D7929 was developed by Subcommittee D18.21.04 on Groundwater Sample Collection and Handling, part of ASTM International Committee D18 on Soil and Rock. Interested volunteers are always welcome to join D18.21.04 in developing proposed new standards.
The subcommittee is currently working on the reinstatement of a practice on low-flow purging and sampling of groundwater. Equipment developers and manufacturers are encouraged to join as are members of both the regulatory and sampling communities.