Trace elements in the leachate of automobile-scrap shredder waste

Leachate from composite samples of automobile-scrap shredder waste was analyzed for trace elements by inductively coupled plasma atomic emission spectrometry, according to the USEPA Toxicity Characteristic Leaching Procedure for solid waste (TCLP). Analytical results confirmed the existence of several environmentally important elements such as barium, cadmium, copper and lead. However, the concentrations of these elements were below the USEPA regulatory limits for the leachate of solid waste. It was also found that representative average values for trace elements, as well as their variability in the leachate of such heterogeneous solid waste, can be arrived at by analyzing composite samples rather than single samples, if a stratified sample selection and composition plan were implemented. Effect of extraction fluids used in the TCLP method was also investigated. The results indicated that the more acidic extraction fluid can leach more of the elements from the shredder waste, regardless of the selection criterion specified in the method.