Effect of E-waste Recycling on Urinary Metabolites of Organophosphate Flame Retardants and Plasticizers and Their Association with Oxidative Stress.

In this study, three chlorinated (Cl-mOPs) and five nonchlorinated (NCl-mOPs) organophosphate metabolites were determined in urine samples collected from participants living in an electronic waste (e-waste) dismantling area (n = 175) and two reference areas (rural, n = 29 and urban, n = 17) in southern China. Bis(2-chloroethyl) phosphate [BCEP, geometric mean (GM): 0.72 ng/mL] was the most abundant Cl-mOP, and diphenyl phosphate (DPHP, 0.55 ng/mL) was the most abundant NCl-mOP. The GM concentrations of mOPs in the e-waste dismantling sites were higher than those in the rural control site. These differences were significant for BCEP (p < 0.05) and DPHP (p < 0.01). Results suggested that e-waste dismantling activities contributed to human exposure to OPs. In the e-waste sites, the urinary concentrations of bis(2-chloro-isopropyl) phosphate (r = 0.484, p < 0.01), BCEP (r = 0.504, p < 0.01), dibutyl phosphate (r = 0.214, p < 0.05), and DPHP (r = 0.440, p < 0.01) were significantly increased as the concentration of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of DNA oxidative stress, increased. Our results also suggested that human exposure to OPs might be correlated with DNA oxidative stress for residents in e-waste dismantling areas. To our knowledge, this study is the first to report the urinary levels of mOPs in China and examine the association between OP exposure and 8-OHdG in humans.

Efficient Desulfurizer Recycling during Spent Lead-Acid Batteries Paste Disposal by Zero-Carbon Precursor Hypothermic Smelting.

Recycling of spent lead-acid batteries (LABs) is extremely urgent in view of environmental protection and resources reuse. The current challenge is to reduce high consumption of chemical reagents. Herein, a closed-loop spent LABs paste (SLBP) recovery strategy is demonstrated through Na2MoO4 consumption-regeneration-reuse. Experimental and DFT calculations verify that MoO4 2- competes Pb/Ca ions and weakens the metal-oxygen bond of PbSO4/CaSO4.2H2O in SLBP, facilitating PbMoO4/CaMoO4 formation and 99.13 wt% of SO4 2- elimination. Pb of 99.97 wt% is obtained as zero-carbon precursors (PbO2 and PbMoO4) by green leaching coupled with re-crystallization. The regeneration of Na2MoO4 is realized at 600 ℃ using LABs polypropylene shells and NaOH as reagents. Compared with the traditional smelting technologies, the temperature is reduced from ＞1000 to 600 °C. The extraction of Na2MoO4 require only water, and satisfactory re-used desulfurization efficiency (98.67 wt%) is achieved. For the residual Na2MoO4 after first SLBP desulfurization, the desulfurization efficiency remains above 97.36 wt% after adding fresh reagents for two running cycles. The new principle enables the reuse of 99.83 wt% of Na2MoO4 and the recycling of 95.27 wt% of Pb without generating wastewater and slags. The techno-economic analysis indicates this strategy is efficient, economical, and environmentally-friendly.

Urinary benzophenone-type UV filters in people living in South China: rural versus urban areas.

Benzophenone (BP)-type UV filters are widely used in sunscreen products to protect human skin from UV radiation. However, only a few studies have been conducted to determine the level of human exposure to BPs in rural areas of China. In this study, we evaluated the exposure levels of people living in three villages and a city in South China to five major BPs (BP-1, BP-2, BP-3, BP-8, and 4-OH-BP). The detection rates of BP-1, BP-3, and 4-OH-BP were 66%, 72%, and 75%, respectively, in rural areas and 85%, 75%, and 80%, correspondingly, in urban areas. BP-2 and BP-8 were rarely detected. The results indicated that people living in South China are extensively exposed to BPs, regardless of sampling sites (rural and urban areas). The observed concentrations of BP-1 (urban vs. rural = 1.04 ng mL-1vs. 0.21 ng mL-1) and BP-3 (0.37 ng mL-1vs. 0.16 ng mL-1) were significantly (one-way ANOVA, p < 0.01) lower in the rural areas than in the urban areas. BP-1 (59%) based on composition profile analysis was the dominant BP derivative in urine samples of urban residents, whereas 4-OH-BP (36%) was the most prevalent BP in rural areas. In the rural areas, significant positive correlations between urinary BP-1 and BP-3 (r = 0.529, p < 0.01) and between urinary BP-1 and 4-OH-BP (r = 0.323, p < 0.05) concentrations were obtained; in the urban areas, we only observed a clear correlation (p < 0.01) between BP-1 and 4-OH-BP. The different composition profiles and associations among urinary BPs indicated that exposure sources of BPs might be different between rural and urban areas. The distribution profiles of BP-1 and its parent compound (i.e., BP-3) in urine decreased with the age of adults (r = -0.410, p < 0.01) in the rural areas.

Associations between polycyclic aromatic hydrocarbon (PAH) exposure and oxidative stress in people living near e-waste recycling facilities in China.

Emission of polycyclic aromatic hydrocarbons (PAHs) from e-waste recycling activities in China is known. However, little is known on the association between PAH exposure and oxidative damage to DNA and lipid content in people living near e-waste dismantling sites. In this study, ten hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and two biomarkers [8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA)] of oxidative stress were investigated in urine samples collected from people living in and around e-waste dismantling facilities, and in reference population from rural and urban areas in China. The urinary levels of ∑10OH-PAHs determined in e-waste recycling area (GM: 25.4µg/g Cre) were significantly higher (p<0.05) than those found in both rural (11.7µg/g Cre) and urban (10.9µg/g Cre) reference areas. The occupationally exposed e-waste workers (36.6µg/g Cre) showed significantly higher (p<0.01) urinary Σ10OH-PAHs concentrations than non-occupationally exposed people (23.2µg/g Cre) living in the e-waste recycling site. The differences in urinary Σ10OH-PAHs levels between smokers (23.4µg/g Cre) and non-smokers (24.7µg/g Cre) were not significant (p>0.05) in e-waste dismantling sites, while these differences were significant (p<0.05) in rural and urban reference areas; this indicated that smoking is not associated with elevated levels of PAH exposure in e-waste dismantling site. Furthermore, we found that urinary concentrations of Σ10OH-PAHs and individual OH-PAHs were significantly associated with elevated 8-OHdG, in samples collected from e-waste dismantling site; the levels of urinary 1-hydroxypyrene (1-PYR) (r=0.284, p<0.01) was significantly positively associated with MDA. Our results indicate that the exposure to PAHs at the e-waste dismantling site may have an effect on oxidative damage to DNA among selected participants, but this needs to be validated in large studies.