خيارات البحث
النتائج 2361 - 2370 من 4,294
Occurrence and risk assessment of antidepressants in Huangpu River of Shanghai, China
2017
Wu, Minghong | Xiang, Jiajia | Chen, Fenfen | Fu, Cao | Xu, Gang
Antidepressants are gaining public attention because of increasing reports of their occurrence in environment and their potential impact on ecosystems and human health. Continuous input of pharmaceuticals into rivers, through psychiatric hospital or wastewater treatment plant (WWTPs) effluent, may cause adverse effects on the aquatic ecosystems of the receiving water bodies. This work investigates the occurrence and sources of 8 antidepressants in main stream and tributaries of Huangpu River in Shanghai. The detected concentrations of the selected antidepressants ranged from low nanogram per liter to 42.9 ng L⁻¹ (fluoxetine) in main stream and ranged from low nanogram per liter to 33.7 ng L⁻¹ (fluoxetine) in tributaries. To study the effect of hospital or wastewater treatment plants (WWTPs) on environment, the upstream and downstream samples were analyzed. Generally, antidepressants had greater concentrations in downstream than that in upstream of the WWTPs or hospitals. It is suggesting that WWTPs and hospitals may introduce pollution into water environment. A preliminary risk assessment was conducted: none of the eight target compounds yielded risk quotient (RQ) values more than 0.1, thus indicating that no adverse effect is expected in water environment. These results will provide background data for future antidepressants pollution control and management in Shanghai, China.
اظهر المزيد [+] اقل [-]Soil moisture could enhance electrokinetic remediation of arsenic-contaminated soil
2017
Shin, Su-Yeon | Park, Sang-Min | Baek, Kitae
Electrokinetic remediation (EKR) is the most efficient technique for remediation of fine-grained soil. The primary removal mechanisms of heavy metal in EKR are the electromigration and electroosmosis flow under appropriate electric gradients. Most EKR studies have researched the variation according to the electrolyte and electric voltage. Also, EKR could be influenced by the migration velocity of ions, while few studies have investigated the effect of moisture content. In this study, soil moisture was controlled by using tap water and NaOH as electrolytes to enhance electromigration and electroosmosis flow. In both electrolytes, the higher moisture content led to the more As removal efficiency, but there were no differences between tap water and NaOH. Therefore, tap water was the most cost-effective electrolyte to remove As from fine-grained soil.
اظهر المزيد [+] اقل [-]Enhanced Fenton-like degradation of TCE in sand suspensions with magnetite by NTA/EDTA at circumneutral pH
2017
Wang, Na | Jia, Daqing | Jin, Yaoyao | Sun, Sheng-Peng | Ke, Qiang
The present study investigated the degradation of trichloroethylene (TCE) in sand suspensions by Fenton-like reaction with magnetite (Fe₃O₄) in the presence of various chelators at circumneutral pH. The results showed that ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) greatly improved the rate of TCE degradation, while [S,S]-ethylenediaminedisuccinic acid (s,s-EDDS), malonate, citrate, and phytic acid (IP6) have minimal effects on TCE degradation. Quenching tests suggested that TCE was mainly degraded by hydroxyl radical (HO·) attack, with about 90% inhibition on TCE degradation by the addition of HO· scavenger 2-propanol. The presence of 0.1–0.5% Fe₃O₄/sand (w/w) contributed to 40% increase in TCE degradation rates. In particular, the use of chelators can avoid high concentrations of H₂O₂ required for the Fenton-like reaction with Fe₃O₄, and moreover improve the stoichiometric efficiencies of TCE degradation to H₂O₂ consumption. The suitable concentrations of chelators (EDTA and NTA) and H₂O₂ were suggested to be 0.5 and 20 mM, respectively. Under the given conditions, degradation rate constants of TCE were obtained at 0.360 h⁻¹ with EDTA and 0.526 h⁻¹ with NTA, respectively. Enhanced degradation of TCE and decreased usage of H₂O₂ in this investigation suggested that Fenton-like reaction of Fe₃O₄ together with NTA (or EDTA) may be a promising process for remediation of TCE-contaminated groundwater.
اظهر المزيد [+] اقل [-]Distribution of phosphorus-solubilizing bacteria in relation to fractionation and sorption behaviors of phosphorus in sediment of the Three Gorges Reservoir
2017
Liu, Yuqian | Cao, Xiuyun | Li, Hui | Zhou, Zijun | Wang, Siyang | Wang, Zhicong | Song, Chunlei | Zhou, Yiyong
Phosphorus (P) fractionation and sorption behavior as well as the abundance and community composition of phosphorus-solubilizing bacteria (PSB) in sediments, including inorganic phosphate-solubilizing bacteria (IPB) and organic phosphate-mineralizing bacteria (OPB), were investigated in 27 sampling sites of five sections in the Three Gorges Reservoir (TGR) in December 2012. The calcium-bound phosphorus (CaCO₃∼P) accounted for the largest part for P fractions in the sediment of TGR, which was paralleled with IPB outnumbering OPB. Furthermore, some PSB isolates, such as Micromonospora sp., Aminobacter sp., and Arthrobacter sp., were shared by the IPB and OPB. Thus, some IPB species functioned as OPB and vise versa, which could be further reflected by a negative and significant relationship between PSB (IPB + OPB) number and content of CaCO₃∼P together with acid-soluble organic phosphorus (ASOP). Spatially, the highest ASOP content in the section Mudong and the highest CaCO₃∼P plus iron-bound phosphorus (Fe(OOH)∼P) as well as equilibrium phosphorus concentration (EPC₀) in the sections of Yunyang and Zigui due to sediment sequestration by the dam, as well as the positive relationship between EPC₀ and the ratios of different phosphorus species and phosphorus sorption maximum (Q ₘₐₓ), jointly indicated pathway diversification and potential risk of phosphorus release mediated by PSB in TGR.
اظهر المزيد [+] اقل [-]Characterization of rainwater chemical composition after a Southeast Asia haze event: insight of transboundary pollutant transport during the northeast monsoon
2017
Nadzir, Mohd Shahrul Mohd | Lin, Chin Yik | Khan, Md Firoz | Latif, Mohd Talib | Dominick, Doreena | Hamid, Haris Hafizal Abdul | Mohamad, Noorlin | Khairul Nizam Abdul Maulud, | Wahab, Muhammad Ikram Abdul | Kamaludin, Nurul Farahana | Lazim, Mohamad Azwani Shah Mat
Open biomass burning in Peninsula Malaysia, Sumatra, and parts of the Indochinese region is a major source of transboundary haze pollution in the Southeast Asia. To study the influence of haze on rainwater chemistry, a short-term investigation was carried out during the occurrence of a severe haze episode from March to April 2014. Rainwater samples were collected after a prolonged drought and analyzed for heavy metals and major ion concentrations using inductively coupled plasma mass spectroscopy (ICP-MS) and ion chromatography (IC), respectively. The chemical composition and morphology of the solid particulates suspended in rainwater were examined using a scanning electron microscope coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). The dataset was further interpreted using enrichment factors (EF), statistical analysis, and a back trajectory (BT) model to find the possible sources of the particulates and pollutants. The results show a drop in rainwater pH from near neutral (pH 6.54) to acidic (<pH 4.00) during the haze to non-haze transitional period, suggesting that the deposition rate of sulfate and nitrate in the atmosphere via the precipitation process was relatively lower compared to the mineral components. Zinc, nitrate, and calcium, which were the predominant elements in the first rainwater samples. Besides, the results of the SEM-EDS indicated that the zinc was possibly originated from anthropogenic activities which are consistent with the results obtained from EF. The BT model showed that pollutants transported from the mainland of Indo-China and the marine region in the South China Sea were responsible for the high pollution event in the study area. These findings can be useful in identifying contributions of pollutants from single or multiple sources in rainwater samples during haze episodes.
اظهر المزيد [+] اقل [-]Putative mechanisms of genotoxicity induced by fluoride: a comprehensive review
2017
Ribeiro, Daniel Araki | Quispe Yujra, Veronica | da Silva, Victor Hugo Pereira | Claudio, Samuel Rangel | Estadella, Debora | de Barros Viana, Milena | Oshima, Celina Tizuko Fujiyama
Genotoxicity is the ability of an agent to produce damage on the DNA molecule. Considering the strong evidence for a relationship between genetic damage and carcinogenesis, to elucidate the putative mechanisms of genotoxicity induced by fluoride are important to measure the degree of risk involved to human populations. The purpose of this article is to provide a comprehensive review on genotoxicity induced by fluoride on the basis of its mechanisms of action. In the last 10 years, all published data showed some evidence related to genotoxicity, which is due to mitochondrial disruption, oxidative stress, and cell cycle disturbances. However, this is an area that still requires a lot of investigation since the published data are not sufficient for clarifying the genotoxicity induced by fluoride. Certainly, the new information will be added to those already established for regulatory purposes as a safe way to promote oral healthcare and prevent oral carcinogenesis.
اظهر المزيد [+] اقل [-]Effects of alkaloid extracts of mesquite pod on the products of in vitro rumen fermentation
2017
de Jesus Pereira, Taiala Cristina | Pereira, Mara Lúcia Albuquerque | Moreira, Jeruzia Vitória | Azevêdo, José Augusto Gomes | Batista, Ronan | de Paula, Vanderlúcia Fonseca | Oliveira, Brena Santos | de Jesus dos Santos, Edileusa
The objective of this study was to evaluate the effects of alkaloid extracts of Prosopis juliflora (Sw.) D.C. pods obtained by two extraction methods as compared with sodium monensin on the gas production kinetic, mitigation of methane, and rumen fermentation products using wheat bran or Tifton 85 hay as substrates, by the semi-automatic in vitro gas production technique. A completely randomized design was adopted, and two natural additives were tested made from mesquite pod (alkaloid extract I and alkaloid extract II) at three levels (3.9, 7.9, and 12 μg), sodium monensin 5 μM (positive control), and no inclusion of additives (negative control). The volume of gases produced by the degradation of the fibrous fraction of wheat bran was influenced by the concentration of the extract I added to the medium, and the amounts of 7.9 and 12 μg were equal to monensin at the lowest value. The degradation rate of the fibrous carbohydrates with additive extract I at 12 μg was lower in relation to monensin. When Tifton 85 hay was utilized, alkaloid extract I provided a shorter colonization time as compared with monensin at the added amounts of 7.9 and 12 μg and higher production of gases from the fibrous fraction but without interfering with the total volume of gases produced during 96 h of fermentation of carbohydrates. In the periods of 12 and 24 h of incubation, utilizing alkaloid extract I, the mean values of methane production with wheat bran and Tifton 85 hay were lower than monensin (p < 0.05) when the respective amounts of 7.9 and 12 μg were added. Alkaloid extract I has similar potential to sodium in reducing production of total gases, methane, and the acetate/propionate ratio.
اظهر المزيد [+] اقل [-]Traffic aerosol lobar doses deposited in the human respiratory system
2017
Manigrasso, Maurizio | Vernale, Claudio | Avino, Pasquale
Aerosol pollution in urban environments has been recognized to be responsible for important pathologies of the cardiovascular and respiratory systems. In this perspective, great attention has been addressed to Ultra Fine Particles (UFPs < 100 nm), because they efficiently penetrate into the respiratory system and are capable of translocating from the airways into the blood circulation. This paper describes the aerosol regional doses deposited in the human respiratory system in a high-traffic urban area. The aerosol measurements were carried out on a curbside in downtown Rome, on a street characterized by a high density of autovehicular traffic. Aerosol number-size distributions were measured by means of a Fast Mobility Particle Sizer in the range from 5.6 to 560 nm with a 1 s time resolution. Dosimetry estimates were performed with the Multiple-Path Particle Dosimetry model by means of the stochastic lung model. The exposure scenario close to traffic is represented by a sequence of short-term peak exposures: about 6.6 × 10¹⁰ particles are deposited hourly into the respiratory system. After 1 h of exposure in proximity of traffic, 1.29 × 10¹⁰, 1.88 × 10¹⁰, and 3.45 × 10¹⁰ particles are deposited in the head, tracheobronchial, and alveolar regions. More than 95 % of such doses are represented by UFPs. Finally, according to the greater dose estimated, the right lung lobes are expected to be more susceptible to respiratory pathologies than the left lobes.
اظهر المزيد [+] اقل [-]Quantitative proteomics analysis reveals the tolerance of Mirabilis jalapa L. to petroleum contamination
2017
Chen, Shuisen | Ma, Hui | Guo, Zhifu | Feng, Yaping | Lin, Jingwei | Zhang, Menghua | Zhong, Ming
Petroleum is not only an important energy resource but is also a major soil pollutant. To gain better insight into the adaptability mechanism of Mirabilis jalapa to petroleum-contaminated soil, the protein profiles of M. jalapa root were investigated using label-free quantitative proteomics technique. After exposing to petroleum-contaminated soil for 24 h, 34 proteins significantly changed their protein abundance and most of the proteins increased in protein abundance (91.18%). Combined with gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses as well as data from previous studies, our results revealed that M. jalapa enhanced tolerance to petroleum by changing antioxidation and detoxification, cell wall organization, amino acid and carbohydrate metabolism, transportation and protein process, and so on. These metabolism alterations could result in the production and secretion of low molecular carbohydrate, amino acid, and functional protein, which enhanced the bioavailability of petroleum and reducing the toxicity of the petroleum. Taken together, these results provided novel information for better understanding of the tolerance of M. jalapa to petroleum stress.
اظهر المزيد [+] اقل [-]Investigations on the effects of etoxazole in the liver and kidney of Wistar rats
2017
Yılmaz, Mehmet | Rencuzogullari, Eyyup | Canli, Mustafa
Pesticides are used to protect crops and to eliminate pests, though non-target organisms such as mammals are also affected from their usage. Etoxazole (organoflourine pesticide) is an acaricide used to combat spider mites which are the parasites of various crops. The present study aims to investigate the effects of etoxazole on the level of MDA (malondialdehyde) and activities of CAT (catalase), GPx (glutathione peroxidase), and AChE (acetylcholinesterase) in liver and kidney tissues of Wistar rats (Rattus norvegicus var. albinos). Rats received etoxazole intraperitoneally with doses of 2.2, 11, and 22 mg/kg b.w./day for 21 days. Control rats received the same volume of the serum physiologic. Following etoxazole exposures, activities of CAT, GPx, and AChE in the liver and kidney of rats significantly decreased at all doses compared to control group. Oppositely, MDA levels in these tissues increased significantly at all doses following etoxazole exposures. The present study demonstrated that etoxazole, at all doses, had toxic effects in the liver and kidney parameters, suggesting their possible use as effective biomarkers in determining the toxic effects of etoxazole. This may suggest that these biomarkers could also be used as a tool to monitor pesticide-affected areas before severe toxic effects begin in non-target animals and humans.
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