[Different leaching procedures for heavy metal toxicity of waste PCBs]

The purpose of this paper is to evaluate the hazardous of heavy metals of waste printed circuit boards (PCBs) by using four kinds of methods (GB 5086.1-1997, GB 5086.2-1997 from China and 1311 (TCLP), 1312 (SPLP) from USA), and the four kinds of methods are compared to choose a better way to identify toxicity characteristics of waste PCBs. The results show that the leaching concentrations of heavy metals (Cu, Pb, Ni, Mn, Zn and Fe) in the leachate after TCLP are much higher than that after the other three kinds of methods, the concentration of Pb is over the standards, so the waste PCBs may be the hazardous solid waste, the TCLP could be the appropriate way to assess the heavy metals hazardous characteristics of waste PCBs. The leaching concentrations by the leaching methods used in China are relatively lower, which could be disadvantageous to control the hazardous wastes. The initial pH and particle size of waste PCBs have great effect on the leachability of heavy metals from waste PCBs.