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النتائج 3981 - 3990 من 4,309
Urinary arsenic, cadmium, manganese, nickel, and vanadium levels of schoolchildren in the vicinity of the industrialised area of Asaluyeh, Iran النص الكامل
2017
Kafaei, Raheleh | Tahmasbi, Rahim | Ravanipour, Masomeh | Vakilabadi, Dariush Ranjbar | Ahmadi, Mehdi | Omrani, Abdolmajid | Ramavandi, Bahman
Asaluyeh is one of the most heavily industrialised areas in the world where gas, petrochemical, and many downstream industries are located. This study aims to survey the biomonitoring of four metals and one metalloid in children living in the vicinity of Asaluyeh area. To do this, we analysed the creatinine-adjusted urinary levels of arsenic (As), cadmium (Cd), vanadium (V), manganese (Mn), and nickel (Ni) in 184 elementary schoolchildren (99 boys and 85 girls) living in Asaluyeh and compared them with a reference population. The comparisons were done for two seasons (spring and fall). The results showed that in the case area (Asaluyeh), the levels of As, V, Mn, and Ni were significantly higher and that of Cd was not significantly higher than the reference city for both seasons. The mean concentration of metal(loid)s in Asaluyeh (case) and Sadabad (reference) area as μg g⁻¹ creatinine was As 2.90 and 2.24, V 0.06 and 0.03, Mn 0.28 and 0.25, Ni 0.54 and 0.29, and Cd 0.31 and 0.28 in spring and As 3.08 and 2.28, V 0.07 and 0.03, Mn 0.30 and 0.26, Ni 0.91 and 0.30, and Cd 0.36 and 0.31 in the fall. Seasonal variations played a key role in determining urinary metal(loid) concentration, as we saw the significant level of As, Cd, V, and Ni in fall than in spring. With regard to the impact of gender on the absorption and accumulation of urinary metal(loid)s, boys showed higher levels of the studied elements, especially for As, than girls as outdoor activities are more popular among boys. Due to the values being lower than those reported in literature, more research is needed on various population groups and other exposure sources in order to judge whether living in the vicinity of the gas and petrochemical industries in Asaluyeh is a threat to nearby residents.
اظهر المزيد [+] اقل [-]Calculation of intercepted runoff depth based on stormwater quality and environmental capacity of receiving waters for initial stormwater pollution management النص الكامل
2017
Peng, Hai-Qin | Liu, Yan | Gao, Xue-Long | Wang, Hong-Wu | Chen, Yi | Cai, Hui-Yi
While point source pollutions have gradually been controlled in recent years, the non-point source pollution problem has become increasingly prominent. The receiving waters are frequently polluted by the initial stormwater from the separate stormwater system and the wastewater from sewage pipes through stormwater pipes. Consequently, calculating the intercepted runoff depth has become a problem that must be resolved immediately for initial stormwater pollution management. The accurate calculation of intercepted runoff depth provides a solid foundation for selecting the appropriate size of intercepting facilities in drainage and interception projects. This study establishes a separate stormwater system for the Yishan Building watershed of Fuzhou City using the InfoWorks Integrated Catchment Management (InfoWorks ICM), which can predict the stormwater flow velocity and the flow of discharge outlet after each rainfall. The intercepted runoff depth is calculated from the stormwater quality and environmental capacity of the receiving waters. The average intercepted runoff depth from six rainfall events is calculated as 4.1 mm based on stormwater quality. The average intercepted runoff depth from six rainfall events is calculated as 4.4 mm based on the environmental capacity of the receiving waters. The intercepted runoff depth differs when calculated from various aspects. The selection of the intercepted runoff depth depends on the goal of water quality control, the self-purification capacity of the water bodies, and other factors of the region.
اظهر المزيد [+] اقل [-]Contrasting roles of phenol and pyrocatechol on the degradation of 4-chlorophenol in a photocatalytic–biological reactor النص الكامل
2017
Zhang, Chaofan | Fu, Liang | Xu, Zhengxue | Xiong, Houfeng | Zhou, Dandan | Huo, Mingxin
Intimate coupling of photocatalysis and biodegradation (ICPB) provides superior treatment for the degradation of bio-recalcitrant compounds, such as chlorophenol. Photocatalytically generated intermediates can be promptly used by the enclosed biofilms. Chlorophenol degradation can theoretically be accelerated by a co-substrate or be compromised by the competition for photocatalytic reactive oxygen species (ROS); however, studies to examine the comparison are limited in number. Non-chlorinated phenols commonly co-exist in real wastewater; thus, we evaluated the influence of phenol (hard to photo-oxidize) and pyrocatechol (easy to photo-oxidize) on the degradation of 4-chlorophenol (4CP). The removal efficiency of 4CP was 51%, which increased to 62% after phenol addition. Meanwhile, the dechlorination efficiency of 4CP increased from 47 to 63%; similarly, the living/dead cell ratio increased from 49/51 to 79/21. However, pyrocatechol addition led to a decrease in 4CP removal efficiency to 32% and a reduction in living/dead cell ratio to 35/65. The differences in the results were attributed to the extra electron donors provided by the photodegraded products of phenol to bacteria, which enhanced 4CP degradation; meanwhile, pyrocatechol competed with 4CP for ROS, thus inhibiting its degradation. Competition for ROS and co-substrate properties should be considered in the treatment of phenolic wastewater by ICPB.
اظهر المزيد [+] اقل [-]Autophagy response in the liver of pigeon exposed to avermectin النص الكامل
2017
Wang, Xian-Song | Liu, Ci | Khoso, Pervez Ahmed | Zheng, Weijia | Li, Ming | Li, Shu
Pesticide residues are an important aspect of environmental pollution. Environmental avermectin residues have produced adverse effects in organisms. Many pesticides exert their toxic effects via the mechanism of autophagy. The purpose of this study was to examine the changes in autophagy levels and in autophagy-related genes, including LC3, Beclin 1, Dynein, ATG5, TORC1, and TORC2, resulting from exposure to subchronic levels of AVM in liver tissue in the king pigeon model. We observed abundant autophagic vacuoles with extensively degraded organelles, autophagosomal vacuoles, secondary lysosomes, and double-membrane structures in the liver. The expression levels of the autophagy-related genes LC3-I, LC3-II, Beclin 1, ATG5, and Dynein were up-regulated; however, TORC1 and TORC2 expression levels were down-regulated. These changes occurred in a concentration-dependent manner after AVM exposure for 30, 60, and 90 days in pigeons. Taken together, these results suggested that AVM increased the autophagic flux and that upregulation of autophagy might be closely related to the hepatotoxicity of AVM in birds.
اظهر المزيد [+] اقل [-]Appraisal of a hybrid air cleaning process النص الكامل
2017
Pierpaoli, Mattia | Giosuè, Chiara | Ruello, Maria Letizia | Fava, Gabriele
Nowadays, there is an amplified interest in maintaining suitable indoor air quality (IAQ). Besides a wide range of available interventions, air cleaners are considered a valuable tool, since based on inexpensive and easily implementing technologies to improve IAQ. The purpose of this work is to combine the TiO₂-photocatalysis with the electrostatic and adsorption processes, in order to improve efficiency and reliability. A TiO₂-photocatalytic oxidation combined with an electrostatic filter has been studied. Nitrogen oxides reduction and degradation of many VOC over different catalyst support were monitored jointly with CO and CO₂ production. The coupling of photocatalysis with an external electric field enhances efficiency of the process. The choice of materials with diversified adsorptive characteristics plays an important role in the durability of the process over time.
اظهر المزيد [+] اقل [-]Surveillance of pesticide residues in fruits and vegetables from Accra Metropolis markets, Ghana, 2010–2012: a case study in Sub-Saharan Africa النص الكامل
2017
Fosu, Paul Osei | Donkor, Augustine | Ziwu, Cephas | Dubey, Brajesh | Kingsford-Adaboh, Robert | Asante, Isaac | Nyarko, Stephen | Tawiah, Rose | Nazzah, Noble
Monitoring of pesticide residues in food commodities of plant origin is part of the regular controls on food to safeguard consumer’s health. This study reports for the first time in Ghana a 3-year (2010–2012) monitoring of pesticide contamination of fruits and vegetables and their health implications. A total of 3483 samples were purchased in notable markets within Accra Metropolis and analysed for pesticide residues, employing the modified quick, easy, cheap, effective, rugged and safe analytical procedure. The results indicated that almost all the fruits and vegetables studied had residues above maximum residue limits (MRLs). The commodities with the greatest concentrations exceeding the European Union (EU) MRLs were long green beans (60.6%) and lettuce (57.1%) with watermelon (10%) and green pepper (8.6%) having the least. The relative occurrence of the pesticides was fenvalerate 11.3%, fenitrothion 5.6%, lambda-cyhalothrin 3.6%, dimethoate 3.2%, permethrin 2.7% and deltamethrin 2.2%. These results will serve as a baseline on which annual or other long-term studies could be compared with, thus emphasizing the need for continuous monitoring programmes to regulate trends of pesticide residues in fruits and vegetables to safeguard the consumers’ health.
اظهر المزيد [+] اقل [-]Food safety aspects of primary environmental contaminants in the edible tissues of roe deer (Capreolus capreolus) النص الكامل
2017
Lehel, József | Zwillinger, Dóra | Bartha, András | Lányi, Katalin | Laczay, Péter
The muscle, liver, kidney and fat samples of 20 roe deer of both sexes originating from a hunting area in central Hungary were investigated for the presence of heavy metals such as As, Cd, Hg and Pb, and their contents were evaluated for possible health risk to consumers. Both As and Hg were found at a level below the limit of detection (< 0.5 mg/kg wet weight) in all samples. The median of the measured Cd concentrations was significantly higher in both the kidney and the liver (p = 0.0011) of bucks than of does. In bucks, Cd levels exceeded the respective maximum limits laid down in the European legislation in four kidney and three muscle samples, whereas in does, the measured concentrations were below the respective limits in all samples. The detected amounts of Pb exceeded the maximum limits in the kidney of one buck and eight does, in the liver of two bucks and six does, in the muscle of six bucks and nine does, whereas in all fat tissues of both bucks and does. The concentration of Pb (p = 0.02) was significantly greater in the kidney of does compared to roebucks. Based on data obtained from the present study, the consumption of organs and tissues of the investigated roe deer could be objectionable from food-toxicological point of view and may pose risk to the high consumers of wild game due to their cadmium and lead contents.
اظهر المزيد [+] اقل [-]Hydrogen fluoride (HF) substance flow analysis for safe and sustainable chemical industry النص الكامل
2017
Kim, Junbeum | Hwang, Yongwoo | Yoo, Mijin | Chen, Sha | Lee, Ik-Mo
In this study, the chemical substance flow of hydrogen fluoride (hydrofluoric acid, HF) in domestic chemical industries in 2014 was analyzed in order to provide a basic material and information for the establishment of organized management system to ensure safety during HF applications. A total of 44,751 tons of HF was made by four domestic companies (in 2014); import amount was 95,984 tons in 2014 while 21,579 tons of HF was imported in 2005. The export amount of HF was 2180 tons, of which 2074 ton (China, 1422 tons, U.S. 524 tons, and Malaysia, 128 tons) was exported for the manufacturing of semiconductors. Based on the export and import amounts, it can be inferred that HF was used for manufacturing semiconductors. The industries applications of 161,123 tons of HF were as follows: manufacturing of basic inorganic chemical substance (27,937 tons), manufacturing of other chemical products such as detergents (28,208 tons), manufacturing of flat display (24,896 tons), and manufacturing of glass container package (22,002 tons). In this study, an analysis of the chemical substance flow showed that HF was mainly used in the semiconductor industry as well as glass container manufacturing. Combined with other risk management tools and approaches in the chemical industry, the chemical substance flow analysis (CSFA) can be a useful tool and method for assessment and management. The current CSFA results provide useful information for policy making in the chemical industry and national systems. Graphical abstract Hydrogen fluoride chemical substance flows in 2014 in South Korea.
اظهر المزيد [+] اقل [-]Nutrient changes and biodynamics of Eisenia fetida during vermicomposting of water lettuce (Pistia sp.) biomass: a noxious weed of aquatic system النص الكامل
2017
Suthar, Surindra | Pandey, Bhawna | Gusain, Rita | Gaur, Rubia Zahid | kumar, Kapil
This paper reports the results of vermicomposting of water lettuce biomass (WL) spiked with cow dung at ratios of 20, 40, 60, and 80 % employing Eisenia fetida. A total of four treatments were established and changes in chemical properties of mixtures were observed. Vermicomposting caused a decrease in pH, TOC, volatile solids, and C/N ratio by 1.01–1.08-fold, 0.85–0.92-fold, 0.94–0.96-fold, 0.56–0.70-fold, respectively, but increase in EC, ₜₒₜN, ₜₒₜP, ₜₒₜK, ₜₒₜCa, ₜₒₜZn, ₜₒₜFe, and ₜₒₜCu, by 1.19–1.42-fold, 1.33–1.68-fold, 1.38–1.69-fold, 1.13–1.24-fold, 1.04–1.11-fold, 1.16–1.37-fold, 1.05–1.113-fold, 1.10–1.27-fold, respectively. Overall, the treatment with 60–80 % of WL showed the maximum decomposition and mineralization rates. The earthworm showed the growth and reproduction rate in considerable ranges in all treatment setups but setups with 60–80 % WL proportion exhibited the optimum results. Results reveal that biomass of water lettuce can be utilized effectively for production of valuable manure through vermicomposting system.
اظهر المزيد [+] اقل [-]Biomarkers in Tubifex tubifex for the metalaxyl and metalaxyl-M toxicity assessment in artificial sediment النص الكامل
2017
Di, Shanshan | Liu, Ruiquan | Cheng, Cheng | Chen, Li | Zhang, Wenjun | Tian, Zhongnan | Liu, Chunxiao | Zhou, Zhiqiang | Diao, Jinling
Efficacy and potential environmental risks should be considered when applying enantiopure pesticides. In this study, Tubifex tubifex and its oxidative stress biomarkers were assessed for the toxicity of metalaxyl and metalaxyl-M in sediment. The toxicity assessment was conducted with artificial sediment and reconstituted water. Five test concentrations (from 0 to 100 mg/kg) were set for the short-term (4 days) exposure. The long-term (28 days) exposure was conducted with the environmental concentration (from 0.5 to 5 mg/kg). For the short-term exposure, the increase of superoxide dismutase (SOD) activity was observed, and a clear concentration-response relationship was found in the metalaxyl treatments. The decrease of catalase (CAT) and glutathione peroxidase (GPx) activity could be caused by oxidative stress. The decrease of glutathione (GSH) content and the increase of glutathione-S-transferase (GST) might be due to antioxidation defense and detoxification mechanisms. The increase of malondialdehyde (MDA) might be due to the saturation of antioxidant systems and the accumulation and toxicity of contaminations. In the long-term exposure, the changes of biomarkers in T. tubifex reflected the oxidative stress and detoxification metabolisms. GSH and the related enzymes were important in detoxification processes and involved in the oxidative stress in toxicity mechanism. The long-term direct contact bioassay is sensitive and appropriate to reflect the lower concentration of contaminants.
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