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Structural equation modeling of PAHs in ambient air, dust fall, soil, and cabbage in vegetable bases of Northern China
2018
Zhang, Yunhui | Hou, Deyi | Xiong, GuanNan | Duan, Yonghong | Cai, ChuanYang | Wang, Xin | Li, JingYa | Tao, Shu | Liu, Wenxin
A series of field samples including ambient air (gaseous and particulate phases), dust fall, surface soil, rhizosphere soil and cabbage tissues (leaf, root and core), were collected in vegetable bases near a large coking manufacturer in Shanxi Province, Northern China, during a harvest season. A factor analysis was employed to apportion the emission sources of polycyclic aromatic hydrocarbons (PAHs), and the statistical results indicated coal combustion was the dominant emission source that accounted for different environmental media and cabbage tissues, while road traffic, biomass burning and the coking industry contributed to a lesser extent. A structural equation model was first developed to quantitatively explore the transport pathways of PAHs from surrounding media to cabbage tissues. The modeling results showed that PAHs in ambient air were positively associated with those in dust fall, and a close relationship was also true for PAHs in dust fall and in surface soil due to air-soil exchange process. Furthermore, PAHs in surface soil were correlated with those in rhizosphere soil and in the cabbage leaf with the path coefficients of 0.83 and 0.39, respectively. PAHs in the cabbage leaf may dominantly contribute to the accumulation of PAHs in the edible part of cabbages.
Показать больше [+] Меньше [-]Tissue-specific distribution and bioaccumulation potential of organophosphate flame retardants in crucian carp
2018
Choo, Gyojin | Cho, Hyeon-Seo | Park, Kyunghwa | Yi, Chae-u | Kim, Pilje | Oh, Jeong-Eun
The concentrations, distributions, and bioaccumulation of nine organophosphate flame retardants (OPFRs) were investigated in both abiotic and biotic media, comprising river water, sediment, and crucian carp. The highest concentrations were observed in liver (6.22–18.1 ng/g ww), and the levels in muscle (4.23–7.75 ng/g ww) and gonad (3.08–7.70 ng/g ww) were similar. In whole blood, tris(2-butoxyethyl) phosphate (TBOEP; 31.1–256 ng/mL) accounted for 90% of the total OPFR concentration. Distributions of OPFRs differed between biotic and abiotic media, as tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCIPP), and TBOEP were dominant in abiotic media, whereas triethyl phosphate (TEP), tri-n-butyl phosphate (TNBP), TCEP, and TBOEP dominated in crucian carp. The TNBP had remarkable accumulation potential among nine OPFRs, which the TNBP concentrations in muscle increased with increased total length and body weight. The higher perfusion rate of TNBP to female eggs were observed rather than to male gonads as the concentrations were higher in males than in females, while the opposite results were observed in gonad. Moreover, the concentration of TNBP in female muscle began to decrease near maximum growth as a sexually dimorphic difference in crucian carp. This is the first study to simultaneously investigate the fate of OPFRs in biotic and abiotic media and to show sex differences.
Показать больше [+] Меньше [-]Relationship between bisphenol A exposure and attention-deficit/ hyperactivity disorder: A case-control study for primary school children in Guangzhou, China
2018
Li, Yanru | Zhang, Haibin | Kuang, Hongxuan | Fan, Ruifang | Cha, Caihui | Li, Guanyong | Luo, Zhiwei | Pang, Qihua
Bisphenol A (BPA) is an endocrine-disrupting chemical. Studies have shown that the exposure to BPA is associated with attention-deficit/hyperactivity disorder (ADHD) during adolescent development. However the direct clinical evidence is limited. To investigate the possible association between environmental BPA exposure and the altered behavior of children, a case-control study was conducted with children aged 6–12 years in Guangzhou, China. Two hundred fifteen children diagnosed with ADHD and 253 healthy children from Guangzhou were recruited as the case and control groups, respectively. Urinary BPA and 8-hydroxy-2′-deoxyguanosine (8-OHdG, a biomarker of oxidative DNA damage) concentrations were determined by high-performance liquid chromatography/tandem spectrometry. The results showed that concentrations of urinary BPA for the case group were significantly higher than those for the control group (3.44 vs 1.70 μg/L; 4.63 vs 1.71 μg/g Crt. p < .001). A stepwise increase in the odds ratios for ADHD was observed with the increasing quartiles of children's urinary BPA (first quartile: reference category; second quartile adjusted OR: 1.79, 95% CI: 0.95–3.37; third quartile adjusted OR: 7.44, 95% CI: 3.91–14.1; fourth quartile adjusted OR: 9.41, 95% CI: 4.91–18.1). When the BPA levels were stratified by gender, the odds of ADHD among boys and girls increased significantly with urinary BPA concentrations (adjusted OR: 4.58, 95% CI: 2.84–7.37; adjusted OR: 2.83, 95% CI: 1.17–6.84). Urinary 8-OHdG concentrations in the ADHD children were significantly higher than those in the control group. Furthermore, the linear regression analysis results indicated that a significant relationship existed between BPA exposure and 8-OHdG levels (R = 0.257, p < .001). Our findings provide direct evidence that childhood BPA exposure may be related to ADHD and 8-OHdG concentrations for children. Moreover, BPA exposure could increase the higher occurrence of ADHD for boy than for girls.
Показать больше [+] Меньше [-]Impact of natural organic matter and increased water hardness on DGT prediction of copper bioaccumulation by yellow lampmussel (Lampsilis cariosa) and fathead minnow (Pimephales promelas)
2018
Philipps, Rebecca R. | Xu, Xiaoyu | Mills, Gary L. | Bringolf, Robert B.
We conducted an exposure experiment with Diffusive Gradients in Thin- Films (DGT), fathead minnow (Pimephales promelas), and yellow lampmussel (Lampsilis cariosa) to estimate bioavailability and bioaccumulation of Cu. We hypothesized that Cu concentrations measured by DGT can be used to predict Cu accumulation in aquatic animals and alterations of water chemistry can affect DGT's predict ability. Three water chemistries (control soft water, hard water, and addition of natural organic matter (NOM)) and three Cu concentrations (0, 30, and 60 μg/L) were selected, so nine Cu-water chemistry combinations were used. NOM addition treatments resulted in decreased concentrations of DGT-measured Cu and free Cu ion predicted by Biotic Ligand Model (BLM). Both hard water and NOM addition treatments had reduced concentrations of Cu ion and Cu-dissolved organic matter complexes compared to other treatments. DGT-measured Cu concentrations were linearly correlated to fish accumulated Cu, but not to mussel accumulated Cu. Concentrations of bioavailable Cu predicted by BLM, the species complexed with biotic ligands of aquatic organisms and, was highly correlated to DGT-measured Cu. In general, DGT-measured Cu fit Cu accumulations in fish, and this passive sampling technique is acceptable at predicting Cu concentrations in fish in waters with low NOM concentrations.
Показать больше [+] Меньше [-]Adsorption and regeneration of expanded graphite modified by CTAB-KBr/H3PO4 for marine oil pollution
2018
Xu, Congbin | Jiao, Chunlei | Yao, Ruihua | Lin, Aijun | Jiao, Wentao
The cleaning-up of viscous oil spilled in ocean is a global challenge, especially in Bohai, due to its slow current movement and poor self-purification capacity. Frequent oil-spill accidents not only cause severe and long-term damages to marine ecosystems, but also lead to a great loss of valuable resources. To eliminate the environmental pollution of oil spills, an efficient and environment-friendly oil-recovery approach is necessary. In this study,¹expanded graphite (EG) modified by CTAB-KBr/H₃PO₄ was synthesized via composite intercalation agents of CTAB-KBr and natural flake graphite, followed by the activation of phosphoric acid at low temperature. The resultant modified expanded graphite (M-EG) obtained an interconnected and continuous open microstructure with lower polarity surface, more and larger pores, and increased surface hydrophobicity. Due to these characteristics, M-EG exhibited a superior adsorption capacity towards marine oil. The saturated adsorption capacities of M-EG were as large as 7.44 g/g for engine oil, 6.12 g/g for crude oil, 5.34 g/g for diesel oil and 4.10 g/g for gasoline oil in 120min, exceeding the capacity of pristine EG. Furthermore, M-EG maintained good removal efficiency under different adsorption conditions, such as temperature, oil types, and sodium salt concentration. In addition, oils sorbed into M-EG could be recovered either by a simple compression or filtration-drying treatment with a recovery ratio of 58–83%. However, filtration-drying treatment shows better performance in preserving microstructures of M-EG, which ensures the adsorbents can be recycled several times. High removal capability, fast adsorption efficiency, excellent stability and good recycling performance make M-EG an ideal candidate for treating marine oil pollution in practical application.
Показать больше [+] Меньше [-]Impact of water chemistry on the behavior and fate of copper nanoparticles
2018
Xiao, Yinlong | Vijver, Martina G. | Peijnenburg, Willie J.G.M.
A full-factorial test design was applied to systematically investigate the contribution and significance of water chemistry parameters (pH, divalent cations and dissolved organic carbon (DOC) concentration) and their interactions on the behavior and fate of copper nanoparticles (CuNPs). The total amount of Cu remaining in the water column after 48 h of incubation was mostly influenced by divalent cation content, DOC concentration and the interaction of divalent cations and DOC. DOC concentration was the predominant factor influencing the dissolution of CuNPs, which was far more important than the effect of pH in the range from 6 to 9 on the dissolution of the CuNPs. The addition of DOC at concentrations ranging from 5 to 50 mg C/L resulted in a 3–5 fold reduction of dissolution of CuNPs after 48 h of incubation, as compared to the case without addition of DOC. Divalent cation content was found to be the most influential factor regarding aggregation behavior of the particles, followed by DOC concentration and the interaction of divalent cations and DOC. In addition, the aggregation behavior of CuNPs rather than particulate dissolution explained most of the variance in the sedimentation profiles of CuNPs. These results are meaningful for improved understanding and prediction of the behavior and fate of metallic NPs in aqueous environments.
Показать больше [+] Меньше [-]Airborne microplastics: Consequences to human health?
2018
Prata, Joana Correia
Microplastics have recently been detected in atmospheric fallout in Greater Paris. Due to their small size, they can be inhaled and may induce lesions in the respiratory system dependent on individual susceptibility and particle properties. Even though airborne microplastics are a new topic, several observational studies have reported the inhalation of plastic fibers and particles, especially in exposed workers, often coursing with dyspnea caused by airway and interstitial inflammatory responses. Even though environmental concentrations are low, susceptible individuals may be at risk of developing similar lesions. To better understand airborne microplastics risk to human health, this work summarizes current knowledge with the intention of developing awareness and future research in this area.
Показать больше [+] Меньше [-]Microstructural characteristics of naturally formed hardpan capping sulfidic copper-lead-zinc tailings
2018
Liu, Yunjia | Wu, Songlin | Nguyen, Tuan A.H. | Southam, Gordon | Chan, Ting-Shan | Lu, Ying-Rui | Huang, Longbin
A massive and dense textured layer (ca. 35–50 cm thick) of hardpan was uncovered at the top layer, which capped the unweathered sulfidic Cu-Pb-Zn tailings in depth and physically supported gravelly soil root zones sustaining native vegetation for more than a decade. For the purpose of understanding functional roles of the hardpan layer in the cover profile, the present study has characterized the microstructures of the hardpan profile at different depth compared with the tailings underneath the hardpans. A suit of microspectroscopic technologies was deployed to examine the hardpan samples, including field emission-scanning electron microscopy coupled with energy dispersive spectroscopy (FE-SEM-EDS), X-ray diffraction (XRD) and synchrotron-based X-ray absorption fine structure spectroscopy (XAFS). The XRD and Fe K-edge XAFS analysis revealed that pyrite in the tailings had been largely oxidised, while goethite and ferrihydrite had extensively accumulated in the hardpan. The percentage of Fe-phyllosilicates (e.g., biotite and illite) decreased within the hardpan profile compared to the unweathered tailings beneath the hardpan. The FE-SEM-EDS analysis showed that the fine-grained Ca-sulfate (possibly gypsum) evaporites appeared as platelet-shaped that deposited around pyrite, dolomite, and crystalline gypsum particles, while Fe-Si gels exhibited a needle-like texture that aggregated minerals together and produced contiguous coating on pyrite surfaces. These microstructural findings suggest that the weathering of pyrite and Fe-phyllosilicates coupled with dolomite dissolution may have contributed to the formation of Ca-sulfate/gypsum evaporites and Fe-Si gels. These findings have among the first to uncover the microstructure of hardpan formed at the top layer of sulfidic Cu-Pb-Zn tailings, which physically capped the unweathered tailings in depth and supported root zones and native vegetation under semi-arid climatic conditions.
Показать больше [+] Меньше [-]A comparative study on metal contamination in Estero de Urias lagoon, Gulf of California, using oysters, mussels and artificial mussels: Implications on pollution monitoring and public health risk
2018
Ruiz-Fernández, Ana Carolina | Wu, Rudolf S.S. | Lau, Tai-Chu | Pérez-Bernal, Libia Hascibe | Sánchez-Cabeza, Joan Albert | Chiu, Jill M.Y.
The profile of 11 trace metals in two commonly used biomonitors (the native oyster Crassostrea palmula and mussel Mytella strigata) from Estero de Urias lagoon, Gulf of California, were studied for six months, covering both dry and wet seasons. Metal concentrations in these two bivalves were compared with concentrations accumulated by Artificial Mussels (AMs) deployed alongside during the same period. Significant temporal variations in Cd, Cr and Mn were observed in both bivalve species and AMs. Temporal changes were observed for Fe in both bivalve species, Pb in oyster only and Cu in both AMs and oysters, revealing seasonal changes in inputs and/or chemical forms of these metals in the lagoon. Significant correlations for Cd, Cr and Cu were found in mussels and oysters, but their Co, Fe, Mn and Zn profiles were very different, despite these two species being taxonomically closely related and often used as biomonitors for metals. Interestingly, Hg and U were detected in AMs but not in oysters and mussels. The difference in metal profile in oysters, mussels and AMs revealed in the present study clearly showed that different biomonitors and AM take up metals differentially from the same environment, and metal profile in a single biomonitor or AM alone therefore, cannot provide a good estimate on metal concentrations in the ambient environment. As such, different biomonitors and AM should be used in metal monitoring, in order to provide a comprehensive picture on metal levels in aquatic ecosystems. Concentrations of Ni and Pb in oysters, and Cr, Fe and Mn in mussels were among the highest reported in coastal waters worldwide. Concentrations of Pb in oysters exceeded legal limits set for bivalve mollusks in EU. Concentrations of Cr in mussels and oysters exceeded or were very close to, respectively, the legal limit for fish, crab-meat, oysters, prawns, and shrimps in Hong Kong. The results indicate a potential public health risk on human consumption of oysters and mussels commonly harvested from the Estero de Urias lagoon, and corresponding pollution control measures are deemed necessary.
Показать больше [+] Меньше [-]Baseline characterisation of source contributions to daily-integrated PM2.5 observations at Cape Grim using Radon-222
2018
Crawford, Jagoda | Chambers, Scott D. | Cohen, David D. | Williams, Alastair G. | Atanacio, Armand
We discuss 15 years (2000–2015) of daily-integrated PM₂.₅ samples from the Cape Grim Station. Ion beam analysis and positive matrix factorisation are used to identify six source-type fingerprints: fresh sea salt (57%); secondary sulfate (14%); smoke (13%); aged sea salt (12%); soil dust (2.4%); and industrial metals (1.5%). An existing hourly radon-only baseline selection technique is modified for use with the daily-integrated observations. Results were not significantly different for days on which >20 hours were below the baseline radon threshold compared with days when all 24 hours satisfied the baseline criteria. This relaxed daily baseline criteria increased the number of samples for analysis by almost a factor of two. Two radon baseline thresholds were tested: historic (100 mBq m⁻³), and revised (50 mBq m⁻³). Median aerosol concentrations were similar for both radon thresholds, but maximum values were higher for the 100 mBq m⁻³ threshold. Back trajectories indicated more interaction with southern Australia and the Antarctic coastline for air masses selected with the 100 mBq m⁻³ threshold. Radon-only baseline selection using the 50 mBq m⁻³ threshold was more selective of minimal terrestrial influence than a similar recent study using wind direction and back trajectories. The ratio of concentrations between terrestrial and baseline days for the primary sources soil, smoke and industrial metals was 3.4, 2.6, and 5.5, respectively. Seasonal cycles of soil dust had a summer maximum and winter minimum. Seasonal cycles of smoke were of similar amplitude for terrestrial and baseline events, but of completely different shape: peaking in autumn and spring for terrestrial events, compared to summer for baseline conditions. Seasonal cycles of industrial metals had a summer maximum and winter minimum. A significant fraction of the Cape Grim baseline smoke and industrial metal contributions appeared to be derived from long-term transport (>3 weeks since last terrestrial influence).
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