(a) The comparison study requires analysis of a minimum of 10 samples weighing at least 300 grams each. Samples of PCB remediation waste used in the comparison study must meet the following three requirements.
(1) The samples must either be taken from the PCB remediation waste at the cleanup site, or must be the same kind of material as that waste. For example, if the waste at the cleanup site is sandy soil, you must use the same kind of sandy soil in the comparison study. Do not use unrelated materials such as clay soil or dredged sediments in place of sandy soil.
(2) PCB remediation waste may contain interferences which confound or hamper sample extraction and chemical analysis. These interferences may be from chemicals or other attributes preexisting in the waste material, resulting from the PCB contamination source, or resulting from treatment to remove or destroy PCBs. Comparison study samples must also contain these interfering materials to demonstrate successful analysis in their presence. For example, a PCB remediation waste may have been co-disposed with chlorobenzene solvents or chlorinated pesticides. These chlorinated compounds would have to be present in the comparison study compounds at the same levels found, or at the highest levels expected to be found, in the PCB remediation waste. As another example, for PCB remediation waste which had been solvent washed with liquid amines to remove PCBs, comparison study samples would have to contain concentrations of these amines at the same levels found, or at the highest levels expected to be found, in the PCB remediation waste.
(b) Prior to initiating the comparison study, confirm the following PCB concentrations in the comparison study samples using the methods specified in Sec. 761.292. All samples of non-liquid PCB remediation waste must have PCB concentrations between 0.1 and 150 ppm.
(1) A minimum of three comparison study samples must have PCB concentrations above the cleanup level specified for the site in Sec. 761.61(a)(4) and a minimum of three comparison study samples must have PCB concentrations below the specified cleanup level.
(2) At least one comparison study sample must have a PCB concentration =90 percent and <=100 percent of the cleanup level.
(3) At least one comparison study sample must have a PCB concentration =100 percent and <=110 percent of the cleanup level.
(c) If the comparison study samples do not have the concentrations or concentration ranges required by paragraph (b) of this section, for purposes of use in this chemical extraction and chemical analysis comparison study, a person may adjust PCB concentrations by dilution. Any excess material resulting from the preparation of these samples, which is not used as an analytical sample, is regulated as the PCB concentration in the component having the highest PCB concentration of the component materials in the sample.