1.1 This practice covers a standard procedure for preparing the residual solids obtained at the end of standard methods for biodegradability testing of plastics in solid waste, for subsequent toxicity and compost quality testing. The practice yields mixtures that can be used as such for terrestrial toxicity testing or that can be submitted to water extraction for further aquatic toxicity tests, in accordance with Practice D 5152, and in conjunction with Method D 4229, Guides E 729, E 1192, E 1295, and E 1440, or other currently accepted toxicity test methods (see OECD Guidelines 201, 202, 203, 207, and 208 or U.S. EPA 40FR797A, as well as other documents such as A New Manual for Conducting Microtox Test with the Model 500 Analyzer the work on cyst-based toxicity tests by Centeno, et al). The mixtures can also be used for further soil contact biodegradation testing. 1.2 This practice provides for storage and drying of the mixtures obtained at the end of the test methods for determination of the biodegradability of plastics under controlled composting conditions (Test Method D 5338), and under high-solids anaerobic digestion (Test Method D 5511). The mixtures contain the biologically decomposed residuals from solid waste and from the plastic materials. For the blanks, the residuals will be derived only from the biologically decomposed solid waste. In the event that a particular sample does not pass the toxicity test, chemical characterization of the degradation products can be performed on the sample to determine the source of the toxicity. Description of the performance of these analyses is beyond the scope of this practice. 1.3 There is no ISO standard that is equivalent to this practice. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 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.