5 steps for quality control and quality assurance in groundwater sampling in California

There are varying aspects of stormwater services including groundwater monitoring and sampling. They are a critical part of most subsurface remediation work. Well installations can be monitored via strategically designed well networks that are based on the flow gradient and table of groundwater so as to analyze and monitor subsurface flow. Though the final outcome of a sample collection could be a meager 120ml of water, divided among three sample vials, there are many crucial QC/QA steps that must always be used to ensure that collected samples truly represent the site’s conditions. They include;

Purging the well’s water before colleting sample
The two most accepted well purging methods are; 1): taking between three and five standing water volumes, and 2): pumping the well till its conductance, temperature, and pH level stabilize. Frequently, both methods are combined.

Utilizing new, wrapped throwaway sampling supplies
It’s imperative to prevent cross-contamination when executing any sampling task. If a gas-powered or electric pump is utilized, tubing from unwrapped, new spools must be utilized for every sampling location. Furthermore, new nitrile gloves must be worn during the sampling setup and changed as frequently as necessary till and through the entire sample collections. It’s necessary to change the gloves out immediately before you collect water into sampling jars or vials.

Decontaminating reusable sampling supplies
Equipment comprising pass-through water quality devices, pumps, and gauging probes must be exhaustively decontaminated both before and immediately after use. Firms that offer stormwater services in California can help you with this. A quality detergent must be used for all parts of the equipment that might have come in contact with the purge water, and they must be thoroughly rinsed off with clean, distilled water. All physical contaminations like scale, sediment, or any other debris must be eliminated as a part of the process of decontamination.

Collecting QC (quality control) samples during a particular event
Depending on particular regulatory agency requirements, or the scientist or engineer’s discretion, extra samples might be needed to ensure laboratory quality control. A ‘blind duplicate’, which is an extra set of samples gotten from a particular well, is a good example of a QC sample. The extra samples must be labeled so the sampler is aware of the well serving the blind duplicate, but the lab isn’t abreast of the well’s identification. This enables the third-party data validator or the consultant to assess the laboratory’s capability to offer consistent results.

Protecting and preserving samples properly
Depending on the needed type of analysis and holding times for such, samples might require being placed on ice, or jars or vials used for the sample collection might require the use of a chemical preservative. As sample containers are frequently produced from glass or some other somewhat fragile material or items, the samples must be stored in a way that will prevent any excessive impacts.

With the many varying stormwater services like groundwater monitoring and sampling being compulsory these days, you will certainly need help. You will need to consult with environmental experts that have in-depth knowledge of QC/QA and all other varying areas of groundwater sampling.


Leave a reply