Due to environmental health concerns, exposure to heavy metals and related adverse effects in electronic waste (e-waste) dismantling areas have attracted considerable interest in the recent years. However, little information is available about the Soil/Dust Ingestion Rates (SIR) of heavy metals for children living in such sites. This study estimated the soil ingestion of 66 children from e-waste disassembly areas by collecting and analyzing selected tracer elements in matched samples of their consumed food, feces, and urine, as well as soil samples from their play areas. The concentrations of tracer elements (including Al, Ba, Ce, Mn, Sc, Ti, Y, and V) in these samples were analyzed. The SIR was estimated to be 148.3 mg/day (median) and 383.3 mg/day (95th percentile) based on the Best Tracer Method (BTM). These values are somewhat higher than those observed in America, Canada, and other parts of China. Health risk assessments showed that Cr presented the greatest carcinogenic risk, at more than 10−6 in this typical polluted area, while As was second. These findings provide important insights into the exposure risks of heavy metals in e-waste dismantling sites and emphasize the health risk caused by Cr and As.
Understanding the formation processes of nitrous acid (HONO) is crucial due to its role as a primary source of hydroxyl radicals (OH) in the urban atmosphere and its involvement in haze events. In this study, we propose a new pathway for HONO formation via the UVA-light-promoted photosensitized conversion of nitrogen dioxide (NO 2 ) in the presence of ammonia (NH 3 ) and polycyclic aromatic hydrocarbons (PAHs, common compounds in urban grime). This new mechanism differs from the traditional mechanism, as it does not require the formation of the NO 2 dimer. Instead, the enhanced electronic interaction between the UVA-light excited triplet state of PAHs and NO 2 −H 2 O/NO 2 −NH 3 −H 2 O significantly reduces the energy barrier and facilitates the exothermic formation of HONO from monomeric NO 2 . Furthermore, the performed experiments confirmed our theoretical findings and revealed that the synergistic effect from light-excited PAHs and NH 3 boosts the HONO formation with determined HONO fluxes of 3.6 × 10 10 molecules cm −2 s −1 at 60% relative humidity (RH) higher than any previously reported HONO fluxes. Intriguingly, light-induced NO 2 to HONO conversion yield on authentic urban grime in presence of NH 3 is unprecedented 130% at 60% RH due to the role of NH 3 acting as a hydrogen carrier, facilitating the transfer of hydrogen from H 2 O to NO 2 . These results show that NH 3 -assisted UVA-light-induced NO 2 to HONO conversion on urban surfaces can be a dominant source of HONO in the metropolitan area.
Despite an increasing number of environmental reports on plastic additives, gestational exposure to these chemicals has been poorly characterized. The present work aimed to characterize gestational exposure to a total of 50 broadly used plasticizers and antioxidants in women with fullterm (n = 155) and preterm deliveries (n = 75) and to explore the associations of prenatal exposure with the expressions of placental functionrelated genes. A few of them exhibited significantly different concentrations between the preterm and full-term deliveries group, including 2,6-di-tertbutyl-4-(dimethylamino-methyl)phenol (AO4703), dibutyl fumarate (DBF), tributyl citrate (TBC), triethyl citrate (TEC) 2,4-di-tert-butyl-phenol (2,4-DtBP), 2,4-(1,1,3,3-tetra-methylbutyl)phenol (4-tOP), 2,6-di-tert-butyl-4hydroxytoluene (BHT), and their transformation products. Significant associations were determined between the concentrations of selected chemicals among the 14 substances with detection frequency greater than 60% and the mRNA expression levels of selected genes related to placental functions. The associations also exhibited chemical-specific patterns and significantly differed between preterm and full-term deliveries. Our work represents the first population-based study to assess potential links between gestational exposure to selected plasticizers and antioxidants and placental functions, calling for further efforts to elucidate the potential mechanisms and subsequent impacts on adverse pregnancy outcomes.
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