Groundwater Monitoring Wells

Groundwater well injection—Oxidants may be introduced to the treatment zone through existing or new groundwater monitoring wells as a liquid, gas, or solid. This method relies on the natural migration of oxidants from the well into the formation. Injection wells need to be adequately spaced to allow for oxidant delivery to the entire treatment area. 

Bailers are pipes with an open top and a check valve at the bottom, which are used to retrieve liquid samples from groundwater monitoring wells, tanks, pits, and drums. When a bailer is lowered on a cord into the water, the bottom check valve opens allowing the bailer to fill with water and to sink. As the filled bailer is lifted from the water, the check valve closes to retain the water. A sample is obtained from the bottom end of the bailer by opening the check valve with a bottom-emptying device. 

Kent, T.R. and K.E. Payne. 1996. Sampling groundwater monitoring wells special quality assurance and quality control considerations, Chapter 21. In L.H. Keith (ed.), Principles of Environmental Sampling, 2nd edition, pp. 337-392. American Chemical Society, Washington. 

Rannie, E. H., and Nadon, R. L. (1988). Inexpensive, multi-use, dedicated pump for groundwater monitoring wells. Ground Water Monit. Rev. 8(4), 100—107. 

In some cases, direct measurements of contaminant exposure may be made, such as in the assessment of the steady-state release of an established hazardous waste source. Groundwater monitoring wells or air-sampling devices can be used to determine current exposure concentrations for exposed populations. Commonly, however, air, surface water, and groundwater sampling is neither a logical nor a practical choice. Typical situations in which sampling is not feasible include (i) the evaluation of future exposme and risk to potentially exposed populations and (ii) the potential risk from an event that has yet to occm (e.g. a hazardous waste spill). 

FIGURE 3-9 Cross section of a typical groundwater monitoring well. Groundwater production wells are similar but may be much larger in diameter. 

Kent, R. T. and Payne, K. E., Sampling groundwater monitoring wells. Special QA and QC considerations. In Principles of Environmental Sampling, 2nd ed., Keith, L. H., Ed., American Chemical Society, Washington, DC, 1996, chap. 21. 

For example, contamination was recently noted in the aquifer at Cape Cod, Massachusetts, requiring the Air Force to supply the residents with bottled water. The contamination at Cape Cod was discovered by an environmentalist who noticed chunks of undetonated explosive while touring the range. That forced the Air Force to drill some groundwater monitoring wells and, to everyone s surprise, the aquifer was contaminated with RDX. 

Groundwater monitoring wells or local use of leak detectors... 

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