خيارات البحث
النتائج 4981 - 4990 من 6,560
Radon concentration in drinking water and soil after the September 24, 2019, Mw 5.8 earthquake, Mirpur, Azad Jammu, and Kashmir: an evaluation for potential risk النص الكامل
2020
Muhammad, Said | Riz̤vānullāh, | Turab, Syed Ali | Khan, Muhammad Younis | Khattak, Nimat Ullah | Khan, Muhammad Asif
Radon (²²²Rn), a radioactive gas resulted from the natural decay of other radioactive elements, pose a threat to the exposed human population. Radon gas emits along the seismically active faults and increased the ²²²Rn contamination in sorrounding water and soil. This study investigated the concentration of ²²²Rn in drinking water and soil after the September 24, 2019, Mw 5.8 earthquake, Mirpur District, Azad Jammu, and Kashmir (AJK). For this purpose, water (n = 24) samples were collected from the bore wells of orderly located houses and soil field sampling (n = 12) along with the NE-SW directions of fracture in the Mirpur District. Determined ²²²Rn in drinking water surpassed the maximum contamination level (MCL, 11.1 kBq/m³) set by the US Environmental Protection Agency (US EPA) in 83%, 50%, and 33% of the sampling point at the site I, site II, and site III, respectively. However, that of soil ²²²Rn concentration was observed with the normal range (10–50 kBq/m³). Potential exposure of ²²²Rn consumption in drinking water was the mean effective dose through ingestion (EWᵢₙg, 0.003 ± < 0.001 mSv/a), the effective dose for inhalation (EWIₙₕ, 0.038 ± 0.002 mSv/a), and the total effective dose of human (EWT, 0.041 ± 0.002 mSv/a). Exposure values along with the rupture showed multifold higher risk values (up to 4 times) compared to background sites. These values were observed within the limits (0.1 mSv/a) set by World Health Organization (WHO); however, surpassed the thresholds of the United Nations Scientific Committee on the effects of atomic radiations (UNSCEAR) for all exposure pathways. This study concluded that groundwater in the close vicinity should be avoided or boiled before used for drinking purposes.
اظهر المزيد [+] اقل [-]Radiolytic degradation of anticancer drug capecitabine in aqueous solution: kinetics, reaction mechanism, and toxicity evaluation النص الكامل
2020
Huo, Zhuhao | Wang, Siqi | Shao, Haiyang | Wang, Hongyong | Xu, Gang
The occurrence of anticancer drugs in the environment has attracted wide attention due to its potential environmental risks. The aim of this study was to investigate degradation characteristics and mechanism of anticancer drug capecitabine (CPC) by electron beam (EB) irradiation. The results showed that EB was an efficient water treatment process for CPC. The degradation followed pseudo-first-order kinetics with dose constants ranged from 1.27 to 3.94 kGy⁻¹. Removal efficiencies in natural water filtered or unfiltered were lower than pure water due to the effect of water matrix components. The degradation was restrained by the presence of NO₂⁻, NO₃⁻ and CO₃²⁻, and fulvic acid due to competition of reactive radical •OH. It demonstrated that oxidizing radical played important role in irradiation process. The appropriate addition of H₂O₂ and K₂S₂O₈ providing with oxidizing agents •OH and •SO₄⁻ was favorable to improve degradation efficiency of CPC. The possible transformation pathways of CPC including cleavage of the ribofuranose sugar and defluorination were proposed based on intermediate products and were consistent with the theoretical calculation of charge and electron density distribution. Toxicity of CPC and intermediate products were estimated by ECOSAR program. It was found that CPC was transformed to low toxicity products with EB.
اظهر المزيد [+] اقل [-]Evaluation of Egyptian honeys and their floral origins: phenolic compounds, antioxidant activities, and antimicrobial characteristics النص الكامل
2020
Roby, Mohamed H. H. | Abdelaliem, Yasser Fathy | Esmail, Abdel-Halem Meshref | Mohdaly, Adel A. A. | Ramadan, Mohamed Fawzy
This study reports the physicochemical characterization of clover (Trifolium hybridum) and citrus (Citrus sinensis) honeys produced in Fayoum, Egypt, by evaluating the analysis of moisture content, pH, total soluble solids (TSS), electric conductivity (EC), total sugars, crude protein, ash content, total acidity, hydroxymethylfurfural (HMF), and total phenolic compounds (TPC). Antioxidant and antimicrobial activities of honey extracts and their flower extracts were determined. The results clearly indicated that ethanol gave the highest extraction yield of both clover and citrus flowers, while ethyl acetate showed the highest extraction recovery for the phenolic compounds, with TPC amounting to 338.5 and 536.4 mg gallic acid equivalent kg⁻¹ fresh weight in clover and citrus flower extracts, respectively. Honey samples have less TPC than their flowers. The results showed that the TPC of citrus honey and its flowers was higher than clover honey and its flowers, respectively. Antioxidant activity was higher in extracts obtained from citrus flower than extracts of clover flower. The same trend was noticed for honey samples. Both clover and citrus honeys showed antimicrobial effects against tested microorganisms. HPLC analysis showed that p-coumaric acid was the main phenolic component in ethanol extracts of clover and citrus honeys, contributing about 83.0% and 52.2%, respectively. In citrus and clover flower extracts, syringic acid and quercetin were the main phenolics, respectively. It would be expected that characteristics of honey samples are mainly depended on the floral origin of nectar foraged by bees.
اظهر المزيد [+] اقل [-]Associations between observed concentrations of ethylene oxide in whole blood and smoking, exposure to environmental tobacco smoke, and cancers including breast cancer: data for US children, adolescents, and adults النص الكامل
2020
Jain, Ram B.
For the first time, National Health and Nutrition Examination Survey released data on ethylene oxide (ETO) into public domain for US children aged 6–11 years, adolescents aged 12–19 years, and adults aged ≥ 20 years for 2013–2016. This study was undertaken to evaluate the associations between concentrations of ETO in whole blood and smoking, exposure to environmental tobacco smoke (ETS), and self-reported diagnosis of cancers including breast cancer. Both adolescent (29.6 vs. 49.6 pmol/g Hb, p < 0.01) and adult smokers (31.5 vs. 142.7 pmol/g Hb, p < 0.01) were found to have substantially higher adjusted levels of ethylene oxide than nonsmokers. Non-Hispanic blacks had higher levels of ethylene oxide than other race/ethnicities for children and adolescents. Non-Hispanic Asians had higher levels of ethylene oxide than other race/ethnicities for adults. Exposure to ETO measured by the number of smokers smoking inside the home (p < 0.01) and number of days smokers smoked inside the home (p = 0.03) during the prior week was found to be associated with elevated levels of ETO (p < 0.01) among US adults. Increased age was associated with elevated levels of ETO among adolescents (p = 0.02) and adults (p < 0.01) but the reverse was true for children (p = 0.04). For the general US population, levels of ETO were not found to be associated with cancers including breast cancer.
اظهر المزيد [+] اقل [-]Efficacy of spent tea waste as chemically impregnated adsorbent involving ortho-phosphoric and sulphuric acid for abatement of aqueous phenol—isotherm, kinetics and artificial neural network modelling النص الكامل
2020
Pathak, Uttarini | Jhunjhunwala, Aastha | Roy, Ananya | Das, Papita | Kumar, Tarkeshwar | Mandal, Tamal
The current study emphasises on sorptive expulsion of phenol from aqueous solution using ortho-phosphoric acid (STAC-O) and sulphuric acid (STAC-H)-activated biochar derived from spent tea waste. STAC-O and STAC-H were instrumentally anatomised using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), BET surface area and thermal gravimetric analyser. Equilibrium and kinetic data were implemented for the investigative parametric batch study to prospect the influence of adsorbent dosage, contact time, initial concentration and pH for eradication of phenol from aqueous solution. The maximum phenolic removals by STAC-O and STAC-H are 93.59% and 91.024% respectively at the parametric conditions of adsorbent dosage 3 g/l time 2 h, initial phenol concentration 100 mg/l and pH 8. Non-linear regression of adsorption isotherms and kinetics was accomplished using the equilibrium data. Both the specimens were compared, and it delineated that Temkin isotherm model is contented. The maximum adsorption intakes for STAC-H and STAC-O were 185.002 mg/g and 154.39 mg/g respectively. Pseudo-second-order kinetic model was best fitted for portraying the chemisorption phenomena. Boyd kinetic and intra-particle diffusion model were investigated to elucidate the diffusion mechanism involved in the process. Desorption study was employed for determining the regeneration proficiency of the adsorbents using water, ethanol and NaOH with maximum 93% and 51.16% extrusion for STAC-O and STAC-H respectively. The process parameters involved in this study were further analysed using artificial neural network perusal to determine the input–output relationships and data pattern. The overall adsorption study along with cost estimation exhibited that bidirectional activation of spent tea biochar was prospective in abatement of phenol from aqueous media.
اظهر المزيد [+] اقل [-]Constrained optimization model of the volume of initial rainwater storage tank based on ANN and PSO النص الكامل
2020
He, Shengnan | Chen, Wenxue | Mu, Xiangpeng | Cui, Wei
Rainfall runoff pollution is one of the main causes of water quality deterioration in urban water system. Setting up initial rainwater storage tank could be one of the rapid and effective methods to control runoff pollution. In order to speed up the water environment management processes, the Chinese government has adopted the Public-Private-Partnership (PPP) mode in the water environment treatment to deal with the shortage of funds. Ensuring water quality and controlling water environment management cost are key to PPP projects. Therefore, factors such as pollutant accumulation characteristics of the catchment, land space availability, sewage treatment plants capacity, and river water management cost should be considered during the design of the initial rainwater storage tank on the premise of ensuring water quality. The empirical design method can hardly meet these requirements simultaneously. Under the background of PPP water environment treatment project, a constrained economic optimization model of the initial rainwater storage tank was presented in this paper. The relationship between the total cost of the water environment management and the interception rate of the initial rainwater storage tanks was established by means of Artificial Neural Network (ANN), while the penalty function was used to transform the constrained optimization problem into an unconstrained optimization problem. The interception rate of the initial rainwater storage tanks was then optimized by means of Particle Swarm Optimization (PSO), and the designed volume of the storage tanks was calculated according to the relationship between the interception rate of the storage tank and the cumulative runoff of the related catchment. Finally, a case study of a PPP demonstration project in a plain city in China was conducted. The results demonstrated that compared with the specification method, the total volume of the initial rainwater storage tank increased by 38.7%, the interception rate increased by 68.4%, and the total cost of river water treatment decreased by 5.7% under the constraints of land space availability and sewage treatment capacity. In addition, the optimized method proposed in this paper could reflect the pollutant accumulation characteristics of the catchment. It not only reduce the total cost of the water environment management but also effectively reduce the impact of non-point source pollution on urban water system, and could be more widely used in other areas and PPP projects.
اظهر المزيد [+] اقل [-]An innovative approach for the simultaneous quantitative screening of organic plastic additives in complex matrices in marine coastal areas النص الكامل
2020
Castro-Jiménez, Javier | Ratola, Nuno
Aiming the simultaneous determination of widely used organic plastic additives in complex marine matrices, this work proposes a fast and “green” analytical protocol based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) technology. The validation of this innovative method on real matrices (i.e., sediments, mussel, fish, and Posidonia oceanica) indicated a general good performance in all of them for phthalate esters (PAEs), with low blank levels and average method recoveries varying from 54 ± 11 to 71 ± 12%. The best method performance for organophosphate ester (OPE) flame retardants and plasticizers was in biotic matrices (recoveries 52 ± 31 to 86 ± 38%). This application represents an innovative QuEChERS sequence of two dispersive solid-phase extraction (SPE) steps enabling this approach for the determination of important families of organic plastic additives in the marine environment. Indeed, our method allowed the fast screening and simultaneous determination of OPE and PAEs in various sites and matrices subject to different anthropogenic pressure in coastal NW Mediterranean Sea for the first time. ∑₇PAE and ∑₉OPE concentrations of 19–83 and 27–116 ng g⁻¹ dw (fish), of 80–714 and 42–71 ng g⁻¹ dw (mussels), of 192–908 and 47–151 ng g⁻¹ dw (Posidonia oceanica), and of 11–328 and 4–10 ng g⁻¹ dw (sediment) were measured, respectively. Our approach was sensible enough as to detect differences in the (bio)accumulation patterns of the target compounds in various species and/or sites. This application opens new perspectives for environmentally friendly marine environment monitoring and screening campaigns for organic plastic additives. Graphical abstract
اظهر المزيد [+] اقل [-]The role of partisan conflict in environmental sustainability targets of the United States النص الكامل
2020
Akadiri, Seyi Saint | Alola, Andrew Adewale
The prevailing political atmosphere and partisanship in the United States depict the degree of polarization between the two major political parties of the country. Evidently, the polarization between the Democratic Party (DP) and the Republican Party will expectedly drive the partisan conflict to the higher levels. Considering this motivation, this paper examined the role of partisan conflict in the pollutant emissions in the case of the United States. For sound empirical analysis, the impacts of other environmental quality determinants are being examined over the period 1960–2015. In order to present a decent argument that is viable for policy implementation, the study adopts the combined methodologies of Johansen cointegration; the autoregressive distributed lag (ARDL) of Pesaran et al. J Am Stat Assoc 94(446):621–634 (1999); and the Toda and Yamamoto J Econ 66(1–2):225–250 (1995) Granger causality. Empirical outcomes show (i) the kg oil equivalent per capita energy consumed exercise positive and significant impacts on metric tons of per capita CO₂ emissions, and it is the principal determinant of environmental degradation in both the short-run and the long-run (ii) renewable energy consumption and economic growth also exercise negative and significant impacts on metric tons of per capita CO₂ emissions. Based on our empirical findings, we conclude that partisan conflict indirectly plays a significant role in environmental sustainability targets of the United States. Thus, we are of the opinion that the government should avoid heightened partisan conflict among the political parties in order to promote sustainable environmental policies that would enhance sound and clean environment for both the immediate and the future generation.
اظهر المزيد [+] اقل [-]Associations of soluble metals and lung and liver toxicity in mice induced by fine particulate matter originating from a petrochemical complex النص الكامل
2020
Chuang, Hsiao-Chi | Shie, Ruei-Hao | Lee, Chii-Hong | Chio, Chia-Pin | Yuan, Tzu-Hsuen | Lee, Jui-Huan | Chan, Chang-Chuan
Adverse health effects have been observed in nearby residents due to exposure to petrochemical-derived chemicals. The objective of this study was to examine associations of soluble metals with lung and liver toxicity in fine particulate matter (PM₂.₅) in the vicinity of a petrochemical complex. PM₂.₅ was collected in the vicinity of a petrochemical complex of Mailiao Township (Yunlin County, Taiwan) to investigate lung and liver toxicity in BALB/c mice. The PM₂.₅ concentration was 30.2 ± 11.2 μg/m³, and the PM₂.₅ was clustered in major local emissions (19.1 μg/m³) and minor local emissions (14.1 μg/m³) using a k-means clustering model. The PM₂.₅ (50 and 150 μg/kg) and PM₂.₅-equivalent soluble nickel (Ni), vanadium (V), and lead (Pb) concentrations were intratracheally instilled into BALB/c mice. PM₂.₅ and V significantly decreased the tidal volume after exposure (p < 0.05). The peak expiratory flow (PEF) and peak inspiratory flow (PIF)/PEF ratio were significantly altered by 150 μg/kg V (p < 0.05). V and Pb significantly increased total protein and lactate dehydrogenase (LDH) levels in bronchoalveolar lavage fluid (BALF) (p < 0.05). Interleukin (IL)-6 in BALF significantly increased after exposure to Pb (p < 0.05) accompanied by lung inflammatory infiltration. PM₂.₅ and Pb significantly increased levels of 8-isoprostane (p < 0.05). The level of caspase-3 activity significantly increased after exposure to Pb (p < 0.05). LDH in the liver was significantly increased by PM₂.₅ (p < 0.05). 8-Isoprostane in the liver was significantly increased by PM₂.₅ and Pb (p < 0.05). IL-6 in the liver was significantly increased by PM₂.₅, Ni, V, and Pb after exposure (p < 0.05), accompanied by liver inflammatory infiltration. Our results demonstrated that V in PM₂.₅ was associated with an increase in 8-isoprostane for all emissions and major local petrochemical emissions. In conclusion, V contributes to in vivo liver toxicity induced by PM₂.₅ in the vicinity of a petrochemical complex.
اظهر المزيد [+] اقل [-]Spatial distribution and sources of pesticidal persistent organic pollutants in the Hooghly riverine sediment النص الكامل
2020
Khuman, Sanjenbam Nirmala | Bharat, Girija | Chakraborty, Paromita
Given the extensive indiscriminate usage in the past and limited ongoing use, organochlorine pesticides (OCPs) have been widely reported in the Hooghly riverine environment. Hence, surface riverine sediment samples were collected along the urban and suburban transects of the Hooghly River and OCPs were quantified in gas chromatography mass spectrometry (GC-MS). Mean concentration of HCH, DDT, and endosulfan was 5 ng g⁻¹, 10 ng g⁻¹, and 4 ng g⁻¹ respectively. DDT was dominant among all the OCPs and contributed nearly 40% to the total OCPs possibly due to the ongoing use of DDT for vector control programs. Diagnostic ratios suggest recent source of lindane, DDT, and endosulfan. Using OCP concentration from previously published data in surface water during the same time frame, sediment-water partitioning of OCPs was estimated. Excluding α-HCH and γ-HCH in few pockets, majority of the OCPs tend to partition more on to sediment. Comparing the sediment concentration with the sediment quality guideline values, risk on ecological integrities was indicated due to DDT and HCH contamination. Suburban sites indicated higher risk than urban sites according to the calculated sediment quality guideline quotient (SQGQ). A brief review on the approach to pesticidal POP pollution management in India revealed that older management approaches should be replaced with a unique, integrated, and holistic system.
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