Waste printed circuit boards (WPCBs) are resource-rich but hazardous, demanding innovative strategies for post-consumer collection, recycling, and mining for economically precious constituents. A novel technology for disassembling electronic components from WPCBs is proposed, using hot air to melt solders and to separate the components and base boards. An automatic heated-air disassembling equipment was designed to operate at a heating source temperature at a maximum of 260 °C and an inlet pressure of 0.5 MPa. A total of 13 individual WPCBs were subjected to disassembling tests at different preheat temperatures in increments of 20 °C between 80 and 160 °C, heating source temperatures ranging from 220 to 300 °C in increments of 20 °C, and incubation periods of 1, 2, 4, 6, or 8 min. For each experimental treatment, the disassembly efficiency was calculated as the ratio of electronic components released from the board to the total number of its original components. The optimal preheat temperature, heating source temperature, and incubation period to disassemble intact components were 120 °C, 260 °C, and 2 min, respectively. The disassembly rate of small surface mount components (side length ≤ 3 mm) was 40-50% lower than that of other surface mount components and pin through hole components. On the basis of these results, a reproducible and sustainable industrial ecological protocol using steam produced by industrial exhaust heat coupled to electronic-waste recycling is proposed, providing an efficient, promising, and green method for both electronic component recovery and industrial exhaust heat reutilization.

Read more...

Phthalate esters, which are known endocrine disruptors, are ubiquitously present throughout indoor environments. Leaching from building materials may be a major source of phthalate esters. In this study, we evaluated phthalate ester concentrations in dust samples from 64 classrooms located in 50 nursery schools and explored the critical factors affecting phthalate concentrations, especially with regard to building materials. Dust was sampled by a modified vacuuming method, and building materials were assessed using a portable X-ray fluorescence (XRF) analyzer to determine whether they contained polyvinyl chloride. Di-n-butyl phthalate (DBP), di(2-ethylhexyl) phthalate (DEHP), and di-isononyl phthalate (DINP) were the most frequently detected phthalates. Of these, DEHP was the most abundant phthalate, with a geometric mean of 3170 μg/g dust, and concentrations were significantly correlated with the area of polyvinyl chloride (PVC)-verified flooring. DINP, which has not been well-reported in other studies, was the second-most abundant phthalate, with a geometric mean of 688 μg/g dust, and showed a critical relationship with the number of children in the institution and the agency operating the nursery school. This is the first study to verify the sources of phthalates with an XRF analyzer and to evaluate the relationship between phthalate concentrations and PVC-verified materials.

Read more...

Emissions from motor vehicles, industrial processes, power generation, the household combustion of solid fuel, and other sources pollute the ambient air across the globe. The precise chemical and physical features of ambient air pollution, which comprises a myriad of individual chemical constituents, vary around the world due to differences in the sources of pollution, climate, and meteorology, but the mixtures of ambient air pollution invariably contain specific chemicals known to be carcinogenic to humans.

Recent estimates suggest that the disease burden due to air pollution is substantial. Exposure to ambient fine particles was recently estimated to have contributed 3.2 million premature deaths worldwide in 2010, due largely to cardiovascular disease, and 223,000 deaths from lung cancer. More than half of the lung cancer deaths attributable to ambient fine particles were projected to have been in China and other East Asian countries.

The IARC Monographs Programme convened a multidisciplinary Advisory Group that included epidemiologists, toxicologists, atmospheric scientists, cancer biologists, and regulators to make recommendations for the development of a series of Monographs on air pollution. This book provides the updated state-of-the-art overviews from this Advisory Group on topics related to exposure characterization, atmospheric and engineering sciences, epidemiological studies on cancer, results of pertinent cancer bioassays, and data elucidating potential mechanisms of carcinogenicity of compounds related to air pollution.

Despite what is known about the health risks arising from lead paint, such paints are still widely available and used in many countries for decorating the interiors and exteriors of homes. It can also be found in paint in public buildings such as schools and hospitals, as well as on toys, toy jewellery, glazes, furniture, and playground equipment.

Lead poisoning is entirely preventable, yet lead exposure is estimated to account for 0.6% of the global burden of disease, with the highest burden in developing regions. Childhood lead exposure is estimated to contribute to about 600,000 new cases of children with intellectual disabilities every year. . . .

The International Week of Action on Prevention of Lead Poisoning (October 20-26th 2013) is aimed at addressing the lack of awareness of this issue. During the campaign week, the Global Alliance to Eliminate Lead Paint aims, among other actions, to:

Raise awareness about lead poisoning:

•     Highlight countries and partners' efforts to prevent childhood lead poisoning; and
•     Urge further action to eliminate lead paint.

Oct. 18 -- Scientists have agreed to recommend a global ban on the production and use of two toxic substances deemed to be persistent organic pollutants (POPs) and to advance reviews that could lead to restrictions on two others, but failed to take action on one widely used pesticide due to resistance from India.

Wrapping up an Oct. 14-18 meeting in Rome, the Stockholm Convention's POPs Review Committee (POPRC) agreed to recommend the listing of hexachlorobutadiene (HCBD) and chlorinated naphthalenes (CNs) under Annexes A and C of the convention.

Chemicals listed under Annex A are subject to a ban on their production or use, while those under Annex C are subject to measures aimed at reducing or eliminating releases from unintentional production. . . .

The Review Committee also took the first step toward new restrictions on the flame retardant decabromodiphenyl ether (decaBDE) by agreeing that it met the screening criteria for consideration. The committee will now prepare a draft risk profile for decaBDE for consideration at its next annual meeting in 2014. . . .

The Review Committee failed, however, to reach consensus on a European Union proposal for the listing of dicofol, an organochlorine pesticide that is chemically related to DDT. According to the EU, the substance is used in many countries around the world on a wide variety of fruit, vegetables, and ornamental and field crops.