Active Standard ASTM D4646 | Developed by Subcommittee: D34.01.04
Book of Standards Volume: 11.04
Historical (view previous versions of standard)
Significance and Use
This test method is meant to allow for a rapid (24 h) index of a geomedia's sorption affinity for given chemicals or leachate constituents. A large number of samples may be run using this test method to determine a comparative ranking of those samples, based upon the amount of solute sorbed by the geomedia, or by various geomedia or leachate constituents. The 24-h time is used to make the test convenient and also to minimize microbial degradation which may be a problem in longer-timed 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.
While this test method may be useful in determining 24-h Kd values for nonvolatile organic constituents, interlaboratory testing has been carried out only for the nonvolatile inorganic species, arsenic and cadmium. However, the procedure has been tested for single laboratory precision with polychlorinated biphenyls (PCBs) and is believed to be useful for all stable and nonvolatile inorganic, and organic constituents. This test method is not considered appropriate for volatile constituents.
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 and 22 h) to ensure that the soluble concentrations in the solution have reached a steady state by 24 h. Refer to Test Method D 4319
1.1 This test method describes a procedure for determining the sorption affinity of waste solutes by unconsolidated geologic material in aqueous suspension. The waste solute may be derived from a variety of sources such as wells, underdrain systems, or laboratory solutions such as those produced by waste extraction tests like the Test Method D 3987
1.2 This test method is applicable in screening and providing relative rankings of a large number of geomedia samples for their sorption affinity in aqueous leachate/geomedia suspensions. This test method may not exactly simulate sorption characteristics that would occur in unperturbed geologic settings.
1.3 While this procedure may be applicable to both organic and inorganic constituents, care must be taken with respect to the stability of the particular constituents and their possible losses from solution by such processes as degradation by microbes, light, or hydrolysis. This test method should not be used for volatile chemical constituents (see 6.1).
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
D2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass
D3987 Test Method for Shake Extraction of Solid Waste with Water
D4319 Test Method for Distribution Ratios by the Short-Term Batch Method
ICS Number Code 13.080.05 (Examination of soil in general)