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HANDBOOK: GROUNDWATER - METHODOLOGY - VOL. 2
Citation:
U.S. EPA. HANDBOOK: GROUNDWATER - METHODOLOGY - VOL. 2. , EPA/625/6-90/018b, 1990.
Impact/Purpose:
publish information
Description:
The subsurface environment of ground water is characterized by a complex interplay of physical, geochemical and biological forces that govern the release, transport and fate of a variety of chemical substances. There are literally as many varied hydrogeologic settings as there are types and numbers of contaminant sources. In situations where ground-water investigations are most necessary, there are frequently many variables of land and ground-water use and contaminant source characteristics which cannot be fully characterized. The impact of natural ground-water recharge and discharge processes on distributions of chemical constituents is understood for only a few types of chemical species. Also, these processes may be modified by both natural phenomena and man's activities so as to further complicate apparent spatial or temporal trends in water quality. Since so many climatic, demographic and hydrogeologic factors may vary from place to place, or even small areas within specific sites, there can be no single "standardj" approach for assessing and protecting-the quality of ground water that will be applicable in all cases. Despite these uncertainties, investigations are under! way and they are used as a basis for making decisions about the need for, and usefulness of, alternative corrective and preventive actions. Decision makers, therefore, need some assurance that elements of uncertainty are minimized and that hydrogeologic investigations provide reliable results. A purpose of this document is to discuss measures that can be taken to ensure that uncertainties do not undermine our ability to make reliable predictions about the response of contamination to various corrective or preventive measures. EPA conducts considerable research in ground water to support its regulatory needs. In recent years, scientific knowledge about ground-water systems has been increasing rapidly. Researchers in the Office of Research and Development have made improvements in technology for assessing the subsurface, in adapting techniques from other disciplines to successfully identify specific contaminants in ground water, in assessing the behavior of certain chemicals in some geologic materials and in advancing the state-of-the-art of remedial technologies. An important part of EPA's ground-water research program is to transmit research information to decision makers, field managers and the scientific community. This publication has been developed to assist that effort and, additionally, to help satisfy an immediate Agency need to promote the transfer of technology that is applicable to ground-water contamination control and prevention.