I was hoping you could please provide some guidance on Section 18.104.22.168 of the EPA 1311 TCLP method. Specifically, the requirement for particle size reduction (< 1 mm) used during the determination of the appropriate extraction fluid. We are unclear as to the best way to approach the < 1 mm particle size reduction for samples such as rags, cloth, etc. Is the intent that particle size reduction is necessary for these types of samples, and if so, do you have any recommendations on how this can be done? For the < 9.5 mm particle size reduction for the extraction, there is information about not requiring particle size reduction where the surface area per gram of material is equal to or greater than 3.1 cm2 (section 7.1.3). Even though the surface area comment is not included for the < 1 mm particle size reduction (section 22.214.171.124), is the intent the same (i.e., particle size reduction to < 1 mm is not required where the surface area per gram of material is equal to or greater than 3.1 cm2, such as for cloth, paper, etc.)?
Because of the difficulty in reducing the particle size to less than 9.5 mm for samples like cloth, paper and rags, the surface area criteria is used instead of particle size criteria for the extraction procedure. It would be even harder to reduce the particle size for those types of samples to less than the 1 mm called for in the extraction fluid determination procedure. Therefore, the surface area criteria would also apply for the procedure to determine which extraction fluid to use. As you mentioned, the intent is the same.