The effect of particle size reduction of fibrous materials on TCLP results

The TCLP (toxicity characteristic leaching procedure) test is used to determine the mobility of toxic contaminants present in waste materials and to define hazardous wastes under RCRA. The test requires particle size reduction for solids > 9.5 mm. Filamentous wastes do not need particle size reduction if they have a surface area greater than 3.1 cm²/g. However, guidance in this area is open to interpretation, and specific recommendations regarding the testing of carpeting are not available. This paper describes the effect on TCLP test results of three particle size reduction techniques for three types of carpets that were contaminated with lead in a laboratory experiment. Lead levels applied to the carpets ranged from 1-4 g/kg with lead loadings from 53.8-516.7 mg/m². The carpets were vacuumed for 18.5 min/m² prior to testing. The particle size reduction techniques tested include grinding, cutting into strips, and no reduction. The results indicated no significant difference between the particle size reduction methods, but significant differences were seen between the carpet types. No result was greater than the 5 mg/L TCLP limit for lead. However, some were close, indicating that the carpet type and predisposal remediation method may be important factors when disposal of contaminated carpeting is required. Examples are during lead-based paint abatement or home interior cleanups where lead dust is present.