Scoping survey

A central feature of the ER process is characterization. In this context, characterization refers to those investigations, specifically including meas­urements, undertaken to provide information and data about the contami­nation and affected site environment. Characterization steps usually taken include: [23]

• design of the selected remediation option;

• implementation of the remediation option; and

• verification and/or monitoring of the remediation.

Characterization is a necessary prerequisite to provide critical information and data for each assessment step in this process. Multiple characterization activities are common, with each characterization activity focused on gath­ering the information essential for the particular type of assessment being conducted.

While the general process of dealing with a potentially contaminated site is applicable to most problems, it may result in a range of characterization activities that vary widely in terms of scope, cost and schedule. For example, a small ‘hot spot’ of radioactively contaminated soil resulting from a recent small spill may be surveyed, hand shovelled up into a small container for proper disposal elsewhere, and the soil replaced with clean soil in a few hours. The related characterization activities would have amounted to field survey instrument measurements of radiation prior to and after the hand shovelling.

Alternatively, the source of contamination may have been a leak of radioactive material that contaminated not only the surface soil in the immediate vicinity of the leak but also distant areas, the subsurface soils and groundwater. Migration of the contaminant might now threaten the environment and population away from the leaking source. In this instance, the components of the assessment process may be more complex and, con­sequently, the characterization activities may be more in number, more elaborate, and require years to complete.

Major factors to be taken into account in site characterization include:

• Characterization can be a large consumer of project resources. Mistak­enly, its practical importance to solving the problem may not always be understood or appreciated. In some instances, the characterizations may be the ‘last word’ measurements (e. g., for peripheral areas) and, as such, their credibility is vital.

• The amount of characterization should be proportionate to the extent of the likely remediation effort. Over-characterization can result in a disproportionate fraction of the budget being spent on meas­urements, leaving insufficient means to carry out acceptable remediation.

• Characterization should be adequate to allow a properly designed reme­diation; one that does not involve excessive amounts of unnecessary effort or environmental damage.

• Characterization efforts should be sufficient to demonstrate the exist­ence of clean areas and to provide credible assurances that un-remedi­ated areas are safe.

• Characterizations should have a sufficiently broad focus that any other unknown contaminants are detected at a stage when they can be dealt with efficiently.

• The characterization, in the first instance, and the subsequent remedia­tion should not make things worse by ill-advised first attempts that magnify or spread the problem. A guiding principle can be ‘first, do no harm’.

The reader should note that all factors listed above are relevant to the subsequent generation and management of wastes.

Details on characterization methodologies, techniques and instruments can be found in IAEA (1998) and ITRC (2006). Practical experience, including also R&D work, can be found in IAEA (2000). It should be noted that characterization plays an essential role in the end of an ER project to certify compliance with end-state criteria and allow the planned reuse of the site. Details on post-ER characterization are given in IAEA (1999a) . Figure 8.2 shows post-decontamination measurements of soil by Radon company (Russia).

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