【国外标准】 Standard Test Method for 24-Hour Batch-Type Measurement of Volatile Organic Sorption by Soils and Sediments (Withdrawn 2008)

This test method is intended to allow for a rapid (24-h) index Kd of a geomedia’sorption affinity for given chemicals or leachate constituents. A large number of samples may be analyzed using this test method to determine a comparative ranking of those samples, based on the amount of solute sorbed by the geomedia, or by various geomedia or leachate constituents. The 24-h time period is used to make the test convenient as well as to minimize microbial degradation, which may be a problem in longer procedures. While Kd values are directly applicable for screening and comparative ranking purposes, their use in predictive field applications generally requires the assumption that Kd be a fixed value.The 24-h time limit may be sufficient to reach a steady-state Kd. However, to report this determination as a steady-state Kd, this test method should be conducted for intermediate times (for example, 12, 18, 22 h) to ensure that solute concentrations in the solution phase have reached a steady state by 24 h.1.1 This test method describes a procedure for determining the sorption affinity of waste solutes by unconsolidated geologic material in aqueous suspension, for example, soils, fluvial sediments, sedimentary deposits, or any other accumulations of unconsolidated solid particles (for a companion method, for metal solute, see Test Method D 4319). The waste solute may be derived from a variety of sources such as wells, underdrain systems, or laboratory solutions like those produced by waste extraction tests (for example, Test Method D 3987).1.2 This test method is applicable for screening and providing the relative rankings of a large number of samples for their sorption affinity in aqueous leachate/geomedia suspensions. This test method may not simulate closely the sorption characteristics that would occur in unperturbed geologic settings and under flow conditions.1.3 While this test method is intended to be applicable for all soluble organic constituents, care must be taken with respect to the stability of the particular constituents and their possible losses from solution by such processes as volatilization or degradation by microbes, light, or hydrolysis.1.4 The values stated in SI units are to be regarded as the standard.1.5 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.