Qualitative and quantitative determination of heavy metals in waste cellular phones

Twenty four waste cellular phones, manufactured between 2002 and 2011, were selected in order to determine the total heavy metal content in each of their parts (printed circuit boards (PCBs), plastic housing (PH) and liquid crystal display monitors (LCDs)) and compare the results with the permissible limits set by the 2003 Directive on Restriction of Hazardous Substances (RoHS). All the selected samples were pulverized and digested with strong acids. Inductively coupled plasma-mass spectrometry was used to measure the heavy metal content in each sample. The results revealed that concentration levels of the examined heavy metals were higher in PCBs, followed by PH and LCD in that particular order (PCB > PH > LCD). With the exception of Pb and Cr present in PCBs of mobile phones released before the year 2006, all the other metal concentrations were according to the Directive. Concentration levels of Cd, Hg were lower than the permissible limits set by the EU, either before or after the validity of the 2003 RoHS Directive. Considering their significant heavy metal content, coupled with their large quantities produced worldwide in an annual rate, waste cellular phones need to be treated under an environmentally sound management scheme, prioritizing recycling and at the same time eliminating the possibility of any harm.