خيارات البحث
النتائج 291 - 300 من 5,149
Predictors of thallium exposure and its relation with preterm birth النص الكامل
2018
Jiang, Yangqian | Xia, Wei | Zhang, Bin | Pan, Xinyun | Liu, Wenyu | Jin, Shuna | Huo, Wenqian | Liu, Hongxiu | Peng, Yang | Sun, Xiaojie | Zhang, Hongling | Zhou, Aifen | Xu, Shunqing | Li, Yuanyuan
Thallium (Tl) is a well-recognized hazardous toxic heavy metal that has been reported to have embryotoxicity and fetotoxicity. However, little is known about its association with preterm birth (PTB) in humans. We aimed to evaluate the predictors of Tl exposure and assessed its relation with PTB. The study population included 7173 mother-infant pairs from a birth cohort in Wuhan, China. Predictors of Tl concentrations were explored using linear regression analyses, and associations of Tl exposure with risk of PTB or gestational age at birth were estimated using logistic regression or generalized linear models. The geometric mean and median values of urinary Tl concentrations were 0.28 μg/L (0.55 μg/g creatinine) and 0.29 μg/L (0.53 μg/g creatinine). We found that maternal urinary Tl concentrations varied by gestational weight gain, educational attainment, multivitamin and iron supplementations. Women with Tl concentrations higher than 0.80 μg/g creatinine were at higher risk of giving birth prematurely versus those with Tl concentrations lower than 0.36 μg/g creatinine [adjusted odds ratio (95% confidence interval (CI)): 1.55 (1.05, 2.27)], and the association was more pronounced in PTB with premature rupture of membranes (PROM) rather than in PTB without PROM. About 3-fold increase in creatinine-corrected Tl concentrations were associated with 0.99-day decrease in gestational length (95% CI: −1.36, −0.63). This is the first report on the associations between maternal Tl exposure and the risk of PTB.
اظهر المزيد [+] اقل [-]Heavy metals in nectar modify behaviors of pollinators and nectar robbers: Consequences for plant fitness النص الكامل
2018
Xun, Erna | Zhang, Yanwen | Zhao, Jimin | Guo, Jixun
Plants growing in heavy-metal-rich soils can accumulate metals into their nectar. Nectar chemical composition can alter foraging behavior of floral visitors (including pollinators and floral antagonists) and further affect plant reproductive fitness. The role of nectar heavy metals in deterring pollinators (e.g., shortening foraging time) has been recently studied, but their effects on plant reproduction via changes in behaviors of both pollinators and floral antagonists (e.g., nectar robbers) are less understood. We experimentally manipulated four nectar heavy metals (Zn, Cu, Ni, and Pb) in a native ornamental plant, Hosta ensata F. Maekawa, to investigate the effect of nectar metals on plant reproductive success. We also recorded nectar robbing as well as foraging time and visitation rate of pollinators to assess whether nectar metals could alter the behavior of antagonists and mutualists. Although metals in nectar had no significant direct effects on plant reproduction via hand-pollination, we detected their positive indirect effects on components of female fitness mediated by pollinators and nectar robbers. Matching effects on female plant fitness, nectar robbers responded negatively to the presence of metals in nectar, robbing metal-treated flowers less often. Pollinators spent less time foraging on metal-treated flowers, but their visitation rate to metal-treated flowers was significantly higher than to control flowers. Moreover, pollinators removed less nectar from flowers treated with metals. Our results provide the first direct evidence to date that heavy metals in nectar are capable of deterring nectar robbers and modifying pollinator foraging behavior to enhance plant reproductive fitness.
اظهر المزيد [+] اقل [-]Stereoselective degradation and thyroid endocrine disruption of lambda-cyhalothrin in lizards (Eremias argus) following oral exposure النص الكامل
2018
Chang, Jing | Hao, Weiyu | Xu, Yuanyuan | Xu, Peng | Li, Wei | Li, Jianzhong | Wang, Huili
The disturbance of the thyroid system and elimination of chiral pyrethroid pesticides with respect to enantioselectivity in reptiles have so far received limited attention by research. In this study, bioaccumulation, thyroid gland lesions, thyroid hormone levels, and hypothalamus-pituitary-thyroid axis-related gene expression in male Eremias argus were investigated after three weeks oral administration of lambda-cyhalothrin (LCT) enantiomers. In the lizard liver, the concentration of LCT was negatively correlated with the metabolite-3-phenoxybenzoic acid (PBA) level during 21 days of exposure. (+)-LCT exposure induced a higher thyroid follicular epithelium height than (−)-LCT exposure. The thyroxine levels were increased in both treated groups while only (+)-LCT exposure induced a significant change in the triiodothyronine (T3) level. In addition, the expressions of hypothalamus-pituitary-thyroid axis-related genes including thyroid hormone receptors (trs), deiodinases (dios), uridinediphosphate glucuronosyltransferase (udp), and sulfotransferase (sult) were up-regulated after exposure to the two enantiomers. (+)-LCT treatment resulted in higher expression of trs and (−)-LCT exposure led to greater stimulation of dios in the liver, which indicated PBA-induced antagonism on thyroid hormone receptors and LCT-induced disruption of thyroxine (T4) deiodination. The results suggest the (−)-LCT exposure causes higher residual level in lizard liver while induces less disruption on lizard thyroid activity than (+)-LCT.
اظهر المزيد [+] اقل [-]Distribution and potential ecological risk of 50 phenolic compounds in three rivers in Tianjin, China النص الكامل
2018
Zhong, Wenjue | Wang, Donghong | Wang, Zijian
Phenolic compounds widely exist in the surface water of many countries; however, few studies have simultaneously analyzed and evaluated broad-spectrum phenolic compounds in various components of the water environment. Therefore this study analyzed the distribution and potential ecological risk of 50 phenolic compounds in the surface water, sediment and suspended particulate matter of three important rivers in Tianjin, the main heavy industry city with high pollution in China. The qualitative results show that phenolic pollution existed extensively in the three rivers and the kinds of phenolic compounds in the water were relatively higher than in both sediment and suspended particulate matter. The quantitative results show that the phenolic pollution in the wet-season samples was serious than dry-season samples. Meanwhile, total concentrations of phenolic compounds in three components from the Dagu Drainage River (DDR) were all much higher than those in the Beitang Drainage River (BDR) and Yongdingxin River (YDXR). The highest total concentrations of phenolic compounds in three components all appeared in wet-season samples in DDR, and the highest total concentration was 1354 μg/L in surface water, 719 μg/kg dw in suspended particulate matter and 2937 μg/kg dw in sediment, respectively. The ecological risk of phenolic compounds in surface water was evaluated using the quotient method, and phenolic compounds with risk quotient (RQ) > 1 (RQ > 0.3 for YDXR) were identified as priority pollutants. Five kinds of phenolic compounds were identified as priority phenolic compounds in BDR, and the order of risk was 2-cresol > 2,4-xylenol > 2-sec-butylphenol > 2-naphthol > 3-cresol. Six kinds of phenolic compounds were identified as priority phenolic compounds in DDR, and the order of risk was 2-naphthol > p-chloro-m-xylenol > 4-cresol > 3-cresol > 2,4-xylenol > 2,3,6-Trimethylphenol. In YDXR, only phenol, 2-naphthol and 2,4-xylenol were identified as priority phenolic compounds.
اظهر المزيد [+] اقل [-]Presence, mobility and bioavailability of toxic metal(oids) in soil, vegetation and water around a Pb-Sb recycling factory (Barcelona, Spain) النص الكامل
2018
Mykolenko, S. | Liedienov, V. | Kharytonov, M. | Makieieva, N. | Kuliush, T. | Queralt, I. | Marguí, E. | Hidalgo, M. | Pardini, G. | Gispert, M.
The work was conducted to establish contamination from improper disposal of hazardous wastes containing lead (Pb) and antimony (Sb) into nearby soils. Besides other elements in the affected area, the biological role of Sb, its behaviour in the pedosphere and uptake by plants and the food chain was considered. Wastes contained 139532 ± 9601 mg kg−1 (≈14%) Pb and 3645 ± 194 mg kg−1 (≈0.4%) Sb respectively and variability was extremely high at a decimetre scale. Dramatically high concentrations were also found for As, Cd, Cu, Mn, Ni, Sn and Zn. In adjacent natural soils metal(oid)s amounts decreased considerably (Pb 5034 ± 678 mg kg−1, Sb 112 mg kg−1) though largely exceeded the directives for a given soil use. Metal(oid)s potential mobility was assessed by using H2O→KNO3→EDTA sequential extractions, and EDTA extracts showed the highest concentration suggesting stable humus-metal complexes formation. Nevertheless, selected plants showed high absorption potential of the investigated elements. Pb and Sb values for Dittrichia viscosa grown in wastes was 899 ± 627 mg kg−1 and 37 ± 33 mg kg−1 respectively. The same plant showed 154 ± 99 mg kg−1 Pb and 8 ± 4 mg kg−1 Sb in natural soils. Helichrysum stoechas had 323 ± 305 mg kg−1 Pb, and 8 ± 3 mg kg−1 Sb. Vitis vinifera from alongside vineyards contained 129 ± 88 mg kg−1 Pb and 18 ± 9 mg kg−1 Sb, indicating ability for metal uptake and warning on metal diffusion through the food chain. The biological absorption coefficient (BAC) and the translocation factor (TF) assigned phytoextraction potential to Dittrichia viscosa and Foeniculum vulgare and phytostabilization potential to Helichrysum stoechas. Dissolved metal (oid)s in the analysed water strongly exceeded the current directive being a direct threat for livings. Data warned against the high contamination of the affected area in all its compartments. Even though native plants growing in metal-contaminated sites may have phytoremediation potential, high risk of metal diffusion may threat the whole ecosystem.
اظهر المزيد [+] اقل [-]‘Agricultural Waste to Treasure’ – Biochar and eggshell to impede soil antibiotics/antibiotic resistant bacteria (genes) from accumulating in Solanum tuberosum L النص الكامل
2018
Jiao, Wentao | Du, Ruijun | Ye, Mao | Sun, Mingming | Feng, Yanfang | Wan, Jinzhong | Zhao, Yuanchao | Zhang, Zhongyun | Huang, Duan | Du, Daolin | Jiang, Xin
Soil contamination with antibiotics and antibiotic resistant bacteria/genes (ARB/ARGs) has becoming an emerging environmental problem. Moreover, the mixed pollutants' transfer and accumulation from soil to tuberous vegetables has posed a great threat against food security and human health. In this work, the application of two absorbing materials (maize biochar and sulfate modified eggshell) was able to reduce the poisonous effect of soil antibiotics on potato root system by stimulate the dissipation of water-soluble antibiotics in soil; and also improve food quality by increasing potato starch, protein, fat, and vitamins. Meanwhile, both amendments could effectively decrease the classes and the accumulative abundance of ARB and ARGs (sulI, sulII, catI, catII, ermA, ermB) in the edible parts of potato. The lowest abundance of ARGs was detected in the biochar application treatment, with the accumulative ARG level of 8.9 × 10² and 7.2 × 10² copies mL⁻¹ in potato peel (sull + catI + ermA) and tuberous root (sulI), respectively. It is the first study to demonstrate the feasibility of biochar and eggshell derived from agricultural wastes as green absorbing materials to reduce soil antibiotic, ARB, and ARGs accumulation risk in tuberous vegetable.
اظهر المزيد [+] اقل [-]Particulate mercury in ambient air in Shanghai, China: Size-specific distribution, gas–particle partitioning, and association with carbonaceous composition النص الكامل
2018
Han, Deming | Zhang, Jiaqi | Hu, Zihao | Ma, Yingge | Duan, Yusen | Han, Yan | Chen, Xiaojia | Zhou, Yong | Cheng Jinping, | Wang, Wenhua
Mercury (Hg) has a complex atmospheric transformation cycle and acts as a global pollutant. Size-specific particle bound mercury (PBM) was implemented in different functional (industrial, urban and suburban) areas in Shanghai, China. The total concentration of 13-staged PBM (rang of 0.01–18.0 μm) varied of 99.0–611 pg/m3, with an average value of 318 ± 144 pg/m3. The Gaoqiao petrochemical industry (GQPI) site showed the highest concentrations, whereas the suburban Shanghai Jiao Tong University (SJTU) displayed the lowest. The PBM in nucleation, accumulation and coarse modes were 7.63–96.7, 69.5–455, and 9.43–176 pg/m3, respectively, and the fractions of 0.56–1.00 and 0.32–0.56 μm were the two most abundant. Both OC and EC displayed unimodal distribution patterns (peak of 0.56–1.00 μm) at GQPI, while bimodal distributions were observed at urban and suburban sites. Statistically positive correlations between the overall PBM and the corresponding PM and carbonaceous compounds (r = 0.38–0.54, p < 0.01), indicating their similar origins and OC/EC enhanced gaseous mercury forming PBM. The gas–particle partition model predicted gaseous oxidized mercury (GOM) were 253 ± 133, 237 ± 122, and 257 ± 144 pg/m3 for GQPI, SAES and SJTU, respectively. The particle proportions of divalent mercury in the fraction of 0.32–1.00 μm were substantial (>80%), but smaller (<50%) for nucleation and coarse modes. The fraction of 9.90–18.00 μm occupied nearly 50% of the overall dry deposition fluxes of mercury. These finding highlight the emissions from different mercury and OC/EC origins, caused different size-specific distributions of PBM, which further affect their gas-particle partitioning and dry deposition of mercury species.
اظهر المزيد [+] اقل [-]Urinary bisphenol analogues and triclosan in children from south China and implications for human exposure النص الكامل
2018
Chen, Yi | Fang, Jianzhang | Ren, Lu | Fan, Ruifang | Zhang, Jianqing | Liu, Guihua | Zhou, Li | Chen, Dingyan | Yu, Yingxin | Lu, Shaoyou
Bisphenols and triclosan (TCS) are widely used in consumer products. However, knowledge on human exposure to these anthropogenic chemicals has remained limited in China, especially for children. In this study, concentrations of seven bisphenols and TCS were determined in 283 urine samples collected from South China children aged between 3 and 11 years old. Bisphenol A (BPA), bisphenol S (BPS) and TCS were frequently detected in urine samples, with a detection rate of 93%, 89%, and 95%, respectively. Urinary concentrations of Σ7BPs (the sum concentrations of the seven bisphenols) ranged from 0.43 to 31.5 μg/L, with a median value of 0.91 μg/L, while TCS concentrations ranged from < limit of quantification to 21.9 μg/L (median: 0.21 μg/L). BPA was the predominant analogue (median: 0.35 μg/L), accounting for 49.8% of Σ7BPs. The urinary BPA concentrations in children from Guangzhou were significantly greater than those from Shenzhen. Correlation analysis suggested that multiple exposure sources to South China children likely existed for BPA, BPS, and TCS. Age, but not gender, was negatively associated with urinary residues of BPA and BPS (p < 0.05) and positively with TCS concentrations (p < 0.05). The estimated daily intake of Σ7BPs (23.9 ng/kg bw/day) or TCS (5.63 ng/kg bw/day) was below the tolerant reference dose of BPA, indicating no considerable health hazard to South China children.
اظهر المزيد [+] اقل [-]Radiological comparison of a FDNPP waste storage site during and after construction النص الكامل
2018
Connor, D.T. | Martin, P.G. | Pullin, H. | Hallam, K.R. | Payton, O.D. | Yamashiki, Y. | Smith, N.T. | Scott, T.B.
The clean-up effort that is occurring across the region affected by the 2011 Fukushima Daiichi Nuclear Power Plant accident is unprecedented in its magnitude as well as the financial cost that will eventually result. A major component of this remediation is the stripping of large volumes of material from the land surface, depositing this into large waste storage bags before placing these 1 cubic meter bags into specially constructed stores across Fukushima Prefecture.In this work, using an unmanned aerial vehicle to perform radiological surveys of a site, the time-resolved distribution of contamination during the construction of one of these waste storage sites was assessed. The results indicated that radioactive material was progressively leaching from the store into the surrounding environment. A subsequent survey of the site conducted eight months later revealed that in response to this survey and remedial actions, the contamination issue once existing on this site had been successfully resolved. Such results highlight the potential of low-altitude unmanned aerial systems to easily and rapidly assess site-wide changes over time – providing highly-visual results; therefore, permitting for prompt remedial actions to be undertaken as required.Use of UAV radiation mapping and airborne photogrammetry to produce a time-resolved assessment of remediation efforts within a Fukushima temporary storage facility.
اظهر المزيد [+] اقل [-]Multiwall carbon nanotubes modulate paraquat toxicity in Arabidopsis thaliana النص الكامل
2018
Fan, Xiaoji | Chui, Kawai | Lavoie, Michel | Peijnenburg, W.J.G.M. | Zhu, Youchao | Lu, Tao | Fu, Zhengwei | Zhu, Tingheng | Qian, Haifeng
Carbon nanotubes can be either toxic or beneficial to plant growth and can also modulate toxicity of organic contaminants through surface sorption. The complex interacting toxic effects of carbon nanotubes and organic contaminants in plants have received little attention in the literature to date. In this study, the toxicity of multiwall carbon nanotubes (MWCNT, 50 mg/L) and paraquat (MV, 0.82 mg/L), separately or in combination, were evaluated at the physiological and the proteomic level in Arabidopsis thaliana for 7–14 days. The results revealed that the exposure to MWCNT had no inhibitory effect on the growth of shoots and leaves. Rather, MWCNT stimulated the relative electron transport rate and the effective photochemical quantum yield of PSII value as compared to the control by around 12% and lateral root production up to nearly 4-fold as compared to the control. The protective effect of MWCNT on MV toxicity on the root surface area could be quantitatively explained by the extent of MV adsorption on MWCNT and was related to stimulation of photosynthesis, antioxidant protection and number and area of lateral roots which in turn helped nutrient assimilation. The influence of MWCNT and MV on photosynthesis and oxidative stress at the physiological level was consistent with the proteomics analysis, with various over-expressed photosynthesis-related proteins (by more than 2 folds) and various under-expressed oxidative stress related proteins (by about 2–3 folds). This study brings new insights into the interactive effects of two xenobiotics (MWCNT and MV) on the physiology of a model plant.
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