Abstract:
E-waste recycling activities in informal sectors release small particulate matters and heavy metals including polycyclic aromatic hydrocarbon (PAHs) into the atmosphere. These cause human health effects and environmental problems. This research studied concentrations and size distributions of atmospheric particulates, heavy metals and PAHs bound on different inhalable size fractions emitted from informal e-waste recycling activities including manual dismantling, thermal cutting and open burning of cable sheath. The particle samples were collected on quartz fiber filters using an eight- stage cascade impactor with flow rate of 28.3 L/min at breathing
zone of worker. The particles were classified into 9 interval size fractions (10.0-9.0, 9.0-5.8, 5.8-4.7, 4.7-3.3, 3.3-2.1, 2.1-1.1, 1.1-0.65, 0.65-0.43 and <0.43 micron). Heavy metals (Fe, Cr, Zn, Pb, Cu and Mn) were analyzed by Atomic Absorption Spectrophotometer (AAS) and 16 PAHs were analyzed by selected ion monitoring - Gas Chromatograph-Mass Spectrophotometer ( SIM- GC- MS). The results showed that concentrations of inhalable particles emitted from 3 activities during working day were higher than nonworking
day. The concentrations of particles emitted from thermal cutting and open burning of cable sheath were higher than those of manual dismantling in all particle sizes. Size distributions of particles from 3 activities were bimodal distribution. Manual dismantling and open burning of cable sheath have major peaks in coarse mode while thermal cutting has a major peak in accumulation mode. The concentrations of total heavy metals bound on fine and coarse particles during open burning of cable sheath were higher than those on manual dismantling and thermal cutting. The results revealed that heavy metal concentrations emitted from manual dismantling ranking from high to low were Fe, Pb, Cr, Zn and Cu, respectively. The concentrations of heavy metals released during thermal cutting ranking from high to low were Fe, Zn, Pb, Cr, Mn and Cu, respectively while those of open burning of cable sheath were Fe, Cr, Pb,
Zn, Mn and Cu, respectively. The concentrations of PAHs emitted from thermal cutting were bound on coarse particles followed by fine and ultrafine particles, respectively while those during open burning of cable sheath were bound on fine particles followed by coarse and ultrafine particles, respectively. The results showed that the 5 ring PAHs released from thermal cutting and open burning of cable sheath were 59.63% and 55. 67% , respectively, which were the highest fraction of PAHs. Risk assessment of heavy metals through inhalation indicated that exposure of Cr attached on coarse, fine and ultrafine particles during manual dismantling may cause adverse effects on people's health (HQ≥1) in both of male and female while exposure of Pb bound on coarse, fine and ultrafine particles may cause adverse effects on people's health (HQ≥1) in both of male and female except exposure of Pb in coarse particles for female cause adverse health effects on people's health (HQ>10). Exposure of Cr and Pb attached on coarse and fine particles during open burning of cable sheath may cause adverse effects on people's health (HQ≥1) while exposure of heavy metals bound on coarse, fine and ultrafine particles during thermal cutting had no adverse health effects (HQ<1). The estimated lifetime lung cancer risk of PAHs during thermal cutting and open burning of cable sheath were 1.169E-01 and 8.825E-02, respectively.