Electronic waste or `e-waste' is a rapidly growing form of solid waste worldwide. The heavy metals present in various electronic components demand attention because such metals may leach and pose significant health and environmental hazards (U.S. EPA, 2007). Knowledge of the potential of heavy metal leaching from e-waste represents an important contribution for developing U.S. standards for classifying e-waste as hazardous waste. Hazardous elements which leach from a variety of electronics wastes were assessed in laboratory batch studies. Electronic components evaluated included PC cathode ray tubes, PC motherboards, PC mice, television remote controls, and cellular phones. Each component was disassembled and digested using the Toxicity Characteristic Leaching Procedure (TCLP), EPA Method 1312, Method EA NEN 7371 (Dutch Environmental Agency), and Method DEV-S4 (Germany). The extracts were analyzed for lead, cadmium, chromium, silver, and cobalt. The TCLP consistently leached the greatest amounts of all metals; TCLP-soluble lead was extracted well beyond federal limits for several electronic devices. / Department of Natural Resources and Environmental Management

1.1\xWith the emphasis on particulate matter (PM) and persistent organic pollutants (POPs) from uncontrolled sources, this study focused on the ambient air pollution of e-waste recycling regions and the indoor air quality of urban areas in South China.;1.2\xIn the past decades, severe PM and POPs pollutions were recorded in e-waste recycling regions in China. Since the 2010s, more effective measures, stricter regulations and sophisticated dismantling technologies have been implemented in Guiyu and Qingyuan by local authorities. In this study, total suspended particles (TSP), fine particles (PM2.5), gas phase samples, and indoor settled dust were collected simultaneously in the primary recycling areas as well as reference sites in Guiyu and Qingyuan in August, 2013. The results showed that both PM, PCDD/Fs (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans) , PBDEs (polybrominated diphenyl ethers) and PCBs (polychlorinated biphenyls) in ambient air showed significantly reduced levels in the regions, compared with the former corresponding reports. The changed source patterns of the POPs confirmed the environmental effects of the implementation of stricter regulation and advanced technologies in these years. Nevertheless, the remained uncontrolled e-waste recycling activities in Guiyu, including plastics recycling and circuit board baking, still made significant influence to the air environment and resulted in alarming levels of PCDD/Fs (0.73~2.43 pg I-TEQ/m3) in the recycling areas. While in Qingyuan, high environmental PCBs burden was observed both in informal (1737 pg/m3) and formal recycling areas (1075 pg/m3), which could attribute to the uncontrolled dismantling of PCB-contained transformers. The estimated non-cancer risk for children and adults in the recycling regions were 2.7~25.2 and 1.2~3.2, respectively, and moderate cancer risk were found for the residents living in the recycling regions of Guiyu and the vicinage of the formal recycing factory (CR>10-4). The unacceptable estimated risk for both children and adults suggested unsafe air environments in the two recycling regions.;1.4\xCollectively, our results suggest unsatisfactory air quality in both e-waste recycling regions and common urban areas. The air problems could both attribute to the uncontrolled sources of the related spaces. The obtained results firstly indicated that a long way to solve e-waste issues and more effective measures are needed to control the contaminants release and the exposure to the local residents. Secondly, indoor air quality standard for fine particulate matters as well as associated toxicants such as PAHs is urgently needed to guide common populations and communities.;1.5\xKeywords: Air pollution; E-waste recycling; Urban areas; Indoor air; Ambient air; PM2.5; Persistent organic pollutants; Health risk assessment