【国外标准】 Standard Practice for Sampling Surface Soil for Radionuclides

5.1 Soil provides a source material for the determination of selected radionuclides and serves as an integrator of the deposition of airborne materials. Soil sampling should not be used as the primary measurement system to demonstrate compliance with applicable radionuclides in air standards. This should be done by air sampling or by measuring emission rates. Soil sampling does serve as a secondary system, and in many cases, is the only available avenue if insufficient air sampling occurred at the time of an incident. For many insoluble radionuclides, the primary exposure pathway to the general population is by inhalation. The resuspension of transuranic elements has received considerable attention (1, 2)4 and their measurement in soil is one means of establishing compliance with the U.S. Environmental Protection Agency (EPA) guidelines on exposure to transuranic elements. Soil sampling can provide useful information for other purposes, such as plant uptake studies, total inventory of various radionuclides in soil due to atmospheric nuclear tests, and the accumulation of radionuclides as a function of time. A soil sampling and analysis program as part of a preoperational environmental monitoring program serves to establish baseline concentrations. Consideration was given to these criteria in preparing this practice.5.2 Soil collected using this practice and subsequent analysis can be used to monitor radionuclide deposition of emissions from nuclear facilities. The critical factors necessary to provide this information are sampling location, time of sampling, frequency of sampling, sample size, and maintenance of the integrity of the sample prior to analysis. Since the soil is considered to be a heterogeneous medium, multipoint sampling is necessary. The samples must represent the conditions existing in the area for which data are desired.FIG. 1 Soil Sampling Instrument and Use1.1 This practice covers the sampling of surface soil for the purpose of obtaining a sample representative of a particular area for subsequent chemical analysis of selected radionuclides. This practice describes one acceptable approach to collect soil samples for radiochemical analysis.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.