title: Factors affecting TCLP lead leachability from computer CPUs.
abstract: The factors impacting lead leachability from computer central processing units (CPUs) during the toxicity characteristic leaching procedure (TCLP) were investigated. Several CPUs were disassembled and their component materials were decreased in size to meet the requirements of the TCLP. The impact of CPU composition was examined by leaching different combinations of the CPU components. The ferrous metal content of the mixture greatly impacted lead leaching. TCLP lead concentrations of CPUs predicted by leaching the lead-bearing printed wire boards alone were much greater than those measured when the ferrous metal of the CPU was included in the mixture. The leaching of iron and zinc from the galvanized steel components of the CPU created electrochemical conditions where lead was less soluble. Additional size reduction beyond that required by the TCLP did not result in additional lead leaching. As the volume of head space above the leaching solution increased, the concentration of lead measured increased as well.
authors.affiliation: Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL 32611-6450, USA.
authors.forename: Kevin N
authors.initials: KN
authors.lastname: Vann
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Musson
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Townsend
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D003201:Computers; D007501:Iron / Q000032:analysis*; D007854:Lead / Q000032:analysis*; D012972:Sodium Hydroxide / Q000737:chemistry; D014866:Waste Products; D014874:Water Pollutants, Chemical / Q000032:analysis; D015032:Zinc / Q000032:analysis*
chemical_list: D014866:Waste Products; D014874:Water Pollutants, Chemical; D007854:Lead; D012972:Sodium Hydroxide; D007501:Iron; D015032:Zinc; D019342:Acetic Acid