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Результаты 3751-3760 из 4,309
Characterisation and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in soils and plants around e-waste dismantling sites in southern China Полный текст
2017
Wang, Yujie | He, Jiexin | Wang, Shaorui | Luo, Chunling | Yin, Hua | Zhang, Gan
Environmental pollution due to primitive e-waste dismantling activities has been intensively investigated over the last decade in the south-eastern coastal region of China. In the present study, we investigated the distribution and composition of polycyclic aromatic hydrocarbons (PAHs) in soils and plants around e-waste recycling sites in Longtang, Guangdong province, South China. The results indicated that PAH concentrations in rhizosphere soil and non-rhizosphere soil were in the range of 133 to 626 ng/g and 60 to 816 ng/g, respectively, while PAH levels in plant tissue were 96 to 388 ng/g in shoots and 143 to 605 ng/g in roots. PAHs were enriched in rhizosphere soils in comparison with non-rhizosphere soils. The concentrations of PAHs in plant tissues varied greatly among plant cultivars, indicating that the uptake of PAHs by plants is species-dependent. Different profiles of PAHs in the soil and the corresponding plant tissue implied that PAH uptake and translocation by plants were selective.The total daily intakes of PAHs and carcinogenic PAHs through vegetables at the e-waste recycling site were estimated to be 99 and 22 ng/kg/day, respectively, suggesting that potential health risks associated with the consumption of contaminated vegetables should not be ignored.
Показать больше [+] Меньше [-]Nitrogen fertility and abiotic stresses management in cotton crop: a review Полный текст
2017
Khan, Aziz | Tan, Daniel Kean Yuen | Afridi, Muhammad Zahir | Luo, Honghai | Tung, Shahbaz Atta | Ajab, Mir | Shah, Fahad
This review outlines nitrogen (N) responses in crop production and potential management decisions to ameliorate abiotic stresses for better crop production. N is a primary constituent of the nucleotides and proteins that are essential for life. Production and application of N fertilizers consume huge amounts of energy, and excess is detrimental to the environment. Therefore, increasing plant N use efficiency (NUE) is important for the development of sustainable agriculture. NUE has a key role in crop yield and can be enhanced by controlling loss of fertilizers by application of humic acid and natural polymers (hydrogels), having high water-holding capacity which can improve plant performance under field conditions. Abiotic stresses such as waterlogging, drought, heat, and salinity are the major limitations for successful crop production. Therefore, integrated management approaches such as addition of aminoethoxyvinylglycine (AVG), the film antitranspirant (di-1-p-menthene and pinolene) nutrients, hydrogels, and phytohormones may provide novel approaches to improve plant tolerance against abiotic stress-induced damage. Moreover, for plant breeders and molecular biologists, it is a challenge to develop cotton cultivars that can tolerate plant abiotic stresses while having high potential NUE for the future.
Показать больше [+] Меньше [-]Decreased total antioxidant capacity has a larger effect size than increased oxidant levels in urine in individuals with autism spectrum disorder Полный текст
2017
Yui, Kunio | Tanuma, Nasoyuki | Yamada, Hiroshi | Kawasaki, Yohei
Oxidant/antioxidant imbalance may contribute to the pathophysiology of autism spectrum disorder (ASD). We assayed urinary levels of oxidative stress related biomarkers, hexanoyl-lysine (HEL), total antioxidant capacity (TAOC), the DNA methylation biomarker 8-hydroxy-2′-deoxyguanosine (8-OHdG), and plasma levels of superoxide dismutase (SOD), which is major antioxidant enzyme. We examined the relationship between these four biomarkers and social responsiveness in 20 individuals with ASD and in 11 healthy controls. The sex (ASD group, 7/13 vs. control group, 4/7) and age distributions (ASD group, 10.7 ± 5.0 years vs. control group, 14.7 ± 6.3 years) were not significantly different between the groups. Social responsiveness was assessed using the social responsiveness scale (SRS). We used standardized regression coefficients to measure the effect size. The ASD group exhibited significantly lower urinary TAOC levels and significantly elevated urinary HEL levels than the control group. Urinary 8-OHdG levels and plasma SOD levels were not significantly different between the groups. The ASD group showed significantly higher SRS scores than the control group. Plasma SOD levels correlated significantly with urinary TAOC levels. Standardized regression coefficients revealed that TAOC levels had a larger effect size than HEL levels in urine. This study firstly reveals that an imbalance between urinary HEL and TAOC levels in favor of urinary TAOC levels may contribute to impaired social responsiveness in individuals with ASD. Plasma SOD levels may also affect urinary TAOC levels.
Показать больше [+] Меньше [-]Oxidative stress and early DNA damage in workers exposed to iron-rich metal fumes Полный текст
2017
Pandeh, Masoud | Fathi, Saedeh | Zare Sakhvidi, Mohammad Javad | Zavar Reza, Javad | Sedghian, Lyla
Occupational exposure to metal fumes occurs routinely in many occupational settings. The inflammatory response to fumes and metals after exposure could lead to an increase in reactive oxygen species and level of DNA damage. In this study, the level of early DNA damage and oxidative stress was evaluated in a group of steel company (n = 30) and compared to the non-exposed (n = 28) subjects. All DNA damage markers in workers were significantly higher in exposed group in comparison with controls (p < 0.001). Stratified analysis based on smoking showed no significant differences between smoking and comet assay parameters. There was no significant difference between workers and controls in terms of HCT, TIBC, iron, and ferreting. However, HB in controls was significantly lower than exposed group (p < 0.001). A significant increase in catalase activity and MDA serum levels were observed in workers in comparison with controls. These findings suggest for the potential genotoxic effect of iron reach dust. Due to recent findings on the predictive potential of comet assay for cancer development, further, researches should be conducted to investigate the possible biochemical mechanism of such finding.
Показать больше [+] Меньше [-]Excellent performance of cobalt-impregnated activated carbon in peroxymonosulfate activation for acid orange 7 oxidation Полный текст
2017
Huang, Tianyin | Chen, Jiabin | Wang, Zhongming | Guo, Xin | Crittenden, John C.
Cobalt-impregnated activated carbon (GAC/Co) was used to produce sulfate radical (SO₄ ·⁻) from peroxymonosulfate (PMS) in aqueous solution (hereafter called PMS activation). We evaluated its effectiveness by examining the degradation of orange acid 7 (AO7). GAC/Co exhibited high activity to activate PMS to degrade AO7. The degradation efficiency of AO7 increased with increasing dosage of GAC/Co or PMS and elevated temperatures. pH 8 was most favorable for the degradation of AO7 by GAC/Co-activated PMS. The radical quenching experiments indicated that the reactions most likely took place both in the bulk solution and on the surface of GAC/Co. We found that SO₄ ·⁻ played a dominant role in AO7 degradation. Sodium chloride (NaCl) which presents in most dye wastewater had a significant impact on AO7 degradation. Low dosages (<0.4 M) of NaCl showed a slight inhibitory effect, whereas high dosages (0.8 M) increased the reaction rate. HOCl was confirmed as the main contributor for accelerating AO7 degradation with high concentration of NaCl. In a continuous-flow reaction with an empty-bed contact time of 1.35 min, AO7 was not detected in the effluent for 0 to 18.72 L of treated influent volume (156 h) and 85% removal efficiency was still observed after 40.32 L of treated volume (336 h). Finally, the azo bond and the naphthalene structure in AO7 were destroyed and the degradation pathway was proposed.
Показать больше [+] Меньше [-]Responses of growth, malformation, and thyroid hormone-dependent genes expression in Bufo gargarizans embryos following chronic exposure to Pb2+ Полный текст
2017
Chai, Lihong | Li, Yanbin | Chen, Zhihong | Chen, Aixia | Deng, Hongzhang
The aim of this study was to examine the adverse effects of lead (Pb) exposure on Bufo gargarizans embryos. The 96 h-LC₅₀ of Pb²⁺ for B. gargarizans embryos was determined to be 26.6 mg L⁻¹ after an acute test. In the chronic test, B. gargarizans embryos at Gosner stage 3 were exposed to 10~2000 μg Pb²⁺ L⁻¹ during embryogenesis. Total length, weight, developmental stage, and malformation were monitored. In addition, the transcript levels of type II and type III iodothyronine deiodinase (Dio2 and Dio3) and thyroid hormone receptors (TRα and TRβ) were determined to assess the thyroid-disrupting effects of Pb²⁺. Slightly increased growth and development of B. gargarizans embryos were observed at low concentrations of Pb²⁺ (10, 50, and 100 μg L⁻¹), while retarded growth and development were found at high concentrations of Pb²⁺ (1000 and 2000 μg L⁻¹). In addition, Pb²⁺ exposure induced morphological abnormalities, which were characterized by edema at tail, wavy fin, abdominal edema, stunted growth, hyperplasia, and axial flexures in B. gargarizans embryos. Furthermore, our results showed that exposure to 2000 μg Pb²⁺ L⁻¹ decreased the transcript levels of Dio2, TRα, and TRβ, but it increased Dio3 mRNA level. In contrast, exposure to 50 μg Pb²⁺ L⁻¹ increased TRα mRNA level and decreased Dio3 mRNA level. These results suggested that Pb²⁺ might have thyroid-disrupting effects, leading to the disruption of growth and development in B. gargarizans embryos.
Показать больше [+] Меньше [-]Toward multi-day-ahead forecasting of suspended sediment concentration using ensemble models Полный текст
2017
Alizadeh, Mohamad Javad | Jafari Nodoushan, Ehsan | Kalarestaghi, Naghi | Chau, Kwok Wing
This study explores two ideas to made an improvement on the artificial neural network (ANN)-based models for suspended sediment forecasting in several time steps ahead. In this regard, both observed and forecasted time series are incorporated as input variables of the models when applied for more than one lead time. Secondly, least-square ensemble models employing multiple wavelet-ANN models are developed to increase the performance of the single model. For this purpose, different wavelet families are linked with the ANN model and performance of each model is evaluated using error measures. The Skagit River near Mount Vernon in Washington county is selected as the case study. The daily flow discharge and suspended sediment concentration (SSC) in the current day are considered as input variables to predict suspended sediment concentration in the next day. For more lead times, the input structure is updated by adding the forecast of SSC in the previous time step. Results of this study demonstrate that incorporating both observed and predicted variables in the input structure improves performance of conventional models in which those only employ observed time series as input variables. Moreover, ensemble model developed for each lead time outperforms the best single wavelet-ANN model which indicates superiority of the ensemble model over the other one. Findings of this study reveal that acceptable forecasts of daily suspended sediment concentration up to 3 days in advance can be achieved using the proposed methodology.
Показать больше [+] Меньше [-]Retrospective biomonitoring of mercury and other elements in museum feathers of common kestrel Falco tinnunculus using instrumental neutron activation analysis (INAA) Полный текст
2017
Movalli, Paola | Bode, Peter | Dekker, René | Fornasari, Lorenzo | van der Mije, Steven | Yosef, Reuven
This study examines the potential to use instrumental neutron activation analysis (INAA) to explore temporal and geographical variation in exposure to heavy metals and other selected elements in common kestrel Falco tinnunculus using feathers from a natural history collection. The study gathered samples of two breast feathers from each of 16 adult male kestrel specimens from Naturalis Biodiversity Centre, collected in The Netherlands between 1901 and 2001. Feather samples were analysed for more than 50 elements, using INAA at the Reactor Institute Delft. Results (in mg/kg dw) were transformed into ratios of milligram of element per millimetre of feather length. The distribution of the mass fractions and ratios was plotted for each element against time and by geographical area. Observed mass fractions and/or ratios are discussed for selected elements (Hg, Cd, Zn, Pt, Pd, Se, Al, Rb, As, Sb, Cr, V, Cl, Br) known to have, at certain concentrations, adverse effects on raptors. Some samples show mass fractions of certain elements (Cr, Cd, Se, As) above levels known to have adverse effects. We conclude that the analysis of museum feathers using INAA provides reference values for concentrations of selected elements, including those of high societal concern such as Hg and Cd, against which to assess concentrations of these elements in feathers of present-day living raptor populations.
Показать больше [+] Меньше [-]UV-C as a means to combat biofilm proliferation on prehistoric paintings: evidence from laboratory experiments Полный текст
2017
Pfendler, Stéphane | Einhorn, Olympe | Bousta, Faisl | Khatyr, Abderrahim | Alaoui-Sossé, Laurence | Aleya, Lotfi | Alaoui-Sossé, Badr
A laboratory investigation of UV-C effects was conducted over a 62-h period: a much higher dose than in classic UV-C treatment was applied to five pigments and two painting binders used by prehistoric humans. Colorimetric parameters were compared to a control to see if UV-C can change pigment and binder color. Infrared spectroscopy, scanning electron microscopy, inductively coupled plasma and X-ray crystallography were also carried out to confirm colorimetric measurement. In order to understand how microorganism may physically deteriorate paintings, limestone blocks were painted and monitored until their complete colonization by algae, cyanobacteria, fungi and/or mosses. The results show that UV-C has no effect on mineral compounds. Conversely, it is noteworthy that binder color changed under both UV-C light conditions as well as in visible light. Concerning painted blocks, a fast proliferation has been observed with deterioration of the paintings. These results show the high importance of treating biofilm as soon as possible. Moreover, these findings may be a promising avenue inducing cave managers to use friendly UV-C light to treat contaminated cave paintings and also in the prevention of biodeterioration by lampenflora.
Показать больше [+] Меньше [-]Assessment of hospitalization and mortality from exposure to PM10 using AirQ modeling in Ilam, Iran Полный текст
2017
Nikoonahad, Ali | Naserifar, Razi | Alipour, Vali | Poursafar, Ayub | Miri, Mohammad | Ghafari, Hamid Reza | Abdolahnejad, Ali | Nemati, Sepideh | Mohammadi, Amir
The aims of this study were to assess the health impact of PM₁₀ on inhabitants and to investigate the trend of PM₁₀ concentrations in Ilam, Iran, from 2012 to 2015. For these aims, daily average concentration of PM₁₀ was obtained from continuous monitoring stations in the study area. Mortality and morbidity due to PM₁₀ were assessed by AirQ software developed by World Health Organization (WHO). Based on the results, the annual mean concentrations of PM₁₀ in all of years were more than WHO guideline and PM₁₀ concentration had a decreasing trend in this study period. Total mortality attributed to PM₁₀ was found to be 49 cases in 2012, 25 in 2013, and 33 in 2014. Hospital admission due to respiratory diseases was the most impact due to PM₁₀. Increase in relative risk (RR) with every 10 μg/m³ increase in PM₁₀ from 2012 to 2015 years for total mortality, respiratory disease hospitalization, and hospital admissions were 0.6, 0.8, and 0.9%, respectively. The results of this study indicated that air pollution is one of the major problems in this urban area and AirQ model as simple tool can help to design preventive and controlling programs in order to reduce human health effects of pollutants.
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