Environmental Chemistry Laboratory
California Department of Toxic Substances Control
Discarded consumer electronic devices pose a mounting waste handling problem. Heavy metals contained in the circuitry and liquid crystal displays, as well as polybrominated diphenyl ethers (PBDEs) used as flame retardants in the plastic components, may contaminate ground water and enter the food web.
In response to these concerns, a study was undertaken to determine the total and extractable concentrations of regulated elements in electronic waste for comparison with hazardous waste criteria. Several electronic product types (cell phones, computers, microwave ovens, TVs, etc.) were identified, and four devices of each product type (various brands and models), were analyzed for regulated elements and PBDEs. Devices were dismantled individually and were ground to pass a 2mm sieve. To assess total metal content, sub-samples were digested using EPA Method 3050 and analyzed by Inductively Coupled Plasma-Atomic Emission Spectrometry (EPA Method 6010). To measure PBDEs, sub samples were extracted in a microwave oven with dichloromethane:acetone, cleaned up through silica and alumina columns and analyzed by gas chromatography with electron capture detection. Results were extrapolated to the entire device based on relative weights.
All devices tested exceeded at least one hazardous waste criterion, mainly lead and copper. Different profiles of PBDE congeners reflect the different applications of flame retardants. PBDE-209 was the dominant congener followed by PBDE-47 and PBDE-183. As PBDEs are being phased out, replacement flame retardants need to be studied. Depending on waste management practices, significant exposures to workers, global communities and wildlife can occur.