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Risk assessment of some organic contaminants: a case study based on food consumption in Tanta and Ismailia cities, Egypt 全文
2018
Issa, Asmaa Bayoumi | Yassin, Khaled | Loutfy, Naglaa | Ahmed, Mohamed Tawfic
The impact of some organic pollutants on some residents of Tanta and Ismailia cities of Egypt through their consumption of vegetables, fruits and fish (Nile tilapia and catfish) was examined. Residues of organochlorine (OCS) and organophosphorus (OPS) as some polychlorinated biphenyls (PCBS) were compared with pesticides as well maximum residue limits (MRLS). Probable health risk to consumers was also assessed. P, P′-DDT, P, P′-DDE, P, P′-DDD, endrin, α-BHC, (lindane), and hexachlorbenzene (HCB) were the most detected organochlorine compounds, but did not exceed MRLs.However, OPS residues were the most frequently detected contaminants. PCBs congeners 28, 70, 52, and 180 were detected in tilapia fish from Tanta, but congeners 28 and 180 were the only detected congeners in samples collected from Ismailia region. ∑PCBS values in all matrices did not exceed MRLS. Hazard index (HI) exhibited unity for all compounds at 50 the decreasing order: catfish > vegetables > fruits > Nile tilapia in Tanta, while in Ismailia the order was Nile tilapia > fruit > vegetables. Results also revealed that risk values for adults were greater than those of children categories.
显示更多 [+] 显示较少 [-]Exploring an in situ LED-illuminated isothermal micro-calorimetric method to investigating the thermodynamic behavior of Chlorella vulgaris during CO2 bio-fixation 全文
2018
Russel, Mohammad | Liu, Changrui | Alam, Asraful | Wang, Fei | Yao, Jun | Daroch, Maurycy | Shah, Mahfuzur Rahman | Wang, Zhongming
Much endeavor has been dispensed recently to evaluate the potential of CO₂ mitigation by microalgae. We introduce an alternative, novel, LED-illumination isothermal microcalorimetric method to assess the thermodynamic behaviors of microalgae for better understanding of their carbon sequestration capacity. Microalgae thermodynamic behaviors were recorded as power-time curves, and their indices such as total heat evolution (QT), maximum power output (Pₘₐₓ) and heat generated by per algae cell (JN/Q) were obtained. The values for highest (74.80 g L⁻¹) and control sample (0.00 g L⁻¹) of QT, Pₘₐₓ and JN/Q were 20.85 and 2.32 J; 252.17 and 57.67 μW; 7.91 × ⁻⁰⁶ and 8.80 × ⁻⁰⁷ J cell⁻¹, respectively. According to the values of QT, a general order to promote the CO₂ sequestration was found at 74.8 g L⁻¹ > 29.92 g L⁻¹ > 14.96 g L⁻¹ > 7.48 g L⁻¹ > 0 g L⁻¹ of C sources, which directly corresponded to carbon availability in the growth medium. Chlorella vulgaris GIEC-179 showed the highest peak Pₘₐₓ at 74.8 g L⁻¹ concentration which was directly transformed to their biomass during bio-fixation of CO₂ process. This study is applicable for better understanding of CO₂ fixation performance of algae.
显示更多 [+] 显示较少 [-]Substance flow analysis of mercury in Turkey for policy decision support 全文
2018
Civancik, Didem | Yetis, Ulku
Identification and quantification of mercury flows in Turkey are essential for better policy development regarding to the implementation of water-related legislation. To this end, substance flow analysis (SFA) of mercury in Turkey was conducted in order to identify and quantify mercury releases to different environmental compartments and help policy decision makers to better understand their options to reduce mercury flows. For the quantification of mercury flows, United Nations Environment Programme (UNEP) Mercury Toolkit, which is develop by UNEP Chemicals Branch with the aim of assisting countries to develop their own mercury inventory, was used. Results of the study showed that a total of 34.61 t of mercury is released annually from the activities in Turkey to different environmental compartments. It was found that most of the mercury releases were to the atmosphere (74 %) and smaller amounts were to land (21 %) and to water (5 %). Mercury naturally found in the lithosphere was found to be responsible for most of the releases while intentional mercury uses have smaller shares and decreasing importance because of the phasing out of mercury.
显示更多 [+] 显示较少 [-]Comparative study on the toxic effects of some heavy metals on the Nile Tilapia, Oreochromis niloticus, in the Middle Delta, Egypt 全文
2018
Alm-Eldeen, Abeer A. | Donia, Thoria | Alzahaby, Salma
Heavy metals are the most dangerous hazards affecting aquatic biota in Egypt specially the Nile Tilapia, Oreochromis niloticus, which is an important species in commercial fisheries. Some areas were not fully studied to screen the hazards that may affect this economic fish. Therefore, the present study aimed to evaluate the potential hazards of heavy metals on O. niloticus in Al-Gharbiya Governorate in the Middle delta of Egypt. Water and fish samples were collected from Al-Qased canal, Kafr El-Zayaat Nile, El-Maash canal in Al-Gharbiya Governorate plus a reference site which is a fish farm at the Faculty of Agriculture, Damietta University, Damitta Governorate, Egypt. The results showed a significant increase (p < 0.05) in the lead, zinc, magnesium, manganese, and copper levels while showed a significant decrease (p < 0.05) in the iron level in the water from all the investigated areas. Cadmium level was significantly high (p < 0.05) in Kafr El-Zayaat Nile and EL-Maash canal only. These metals were also accumulated in the fish livers and gills. Consequently, ALT and AST activities and creatinine level were significantly (p < 0.05) high in all the investigated areas. Histopathological examination revealed cytoplasmic and nuclear degeneration in the hepatocytes in all the investigated areas. Renal glomeruli and Bowman’s capsule were not completely intact in Al-Qased and El-Maash canals while conspicuous shrinkage of the glomeruli was determined in Kafr El-Zayaat Nile. Furthermore, slight damage in the secondary lamellae was detected in the gill from Al-Qased canal while in the other areas appeared vacuolated or destructed. Finally, spleen sections of fish from different sites showed the absence of melanin pigments and some vacuoles. In conclusion, the Nile Tilapia, Oreochromis niloticus, is affected by the toxic effects of the heavy metals in Al-Gharbiya Governorate in Egypt and this gives an alarm and should be taken into consideration.
显示更多 [+] 显示较少 [-]Sorption and recovery of platinum from simulated spent catalyst solution and refinery wastewater using chemically modified biomass as a novel sorbent 全文
2018
Garole, DipakJ. | Choudhary, BharatC. | Paul, Debajyoti | Borse, AmulraoU.
In this study, Lagerstroemia speciosa biomass modified by polyethylenimine (PEI-LS) was developed as a potential biosorbent for sorption and recovery of platinum(II) from platinum bearing waste solutions. Batch experiments were conducted to study the effect of various parameters on the sorption and recovery of platinum(II) using PEI-LS. The equilibrium time for platinum(II) sorption process was found to be 6 h. Both the sorption kinetics and sorption isotherm data fits pseudo second-order kinetic model and Langmuir isotherm, respectively. The maximum sorption capacity of platinum(II) onto PEI-LS at pH 2 for the studied temperature range (25–45 °C) is in the range of 122–154 mg/g. Evaluation of thermodynamic parameters suggests that the platinum(II) sorption is spontaneous and endothermic in nature. The regeneration of PEI-LS can be achieved using acidic thiourea as an eluent for recovery of platinum from the biosorbent. Fourier transform infrared (FT-IR) analysis suggests many functional groups were involved in platinum(II) sorption onto PEI-LS. Both the scanning electron microscope/energy dispersive spectroscopy (SEM/EDS) and X-ray photoelectron spectroscopy (XPS) analysis suggest a successful modification of raw biomass with PEI. The XPS analysis further concludes that platinum(II) sorption is governed by ion-exchange and co-ordination reaction. Finally, the PEI-LS was shown to recover ≥ 90% of platinum from two simulated solutions: the acid-leached spent catalyst solution and refinery wastewater. The biosorbent developed in this study is a low-cost and eco-friendly media that can be effectively used for platinum recovery from industrial wastewater.
显示更多 [+] 显示较少 [-]Antibiotic residues in liquid manure from swine feedlot and their effects on nearby groundwater in regions of North China 全文
2018
Li, Xiaohua | Liu, Chong | Chen, Yongxing | Huang, Hongkun | Ren, Tianzhi
A survey was conducted in regions of North China to better understand the effect of antibiotic residue pollution from swine feedlots to nearby groundwater environment. A total of nine experimental sites located in the regions of Beijing, Hebei, and Tianjin were selected to analyze the presence of residues of 11 most commonly used antibiotics, including tetracyclines (TCs), fluoroquinolones (FQNs), sulfonamides (SAs), macrolides, and fenicols, by using liquid chromatography spectrometry. The three most common antibiotics were TCs, FQNs, and SAs, with mean concentrations of 416.4, 228.8, and 442.4 μg L⁻¹ in wastewater samples; 19.9, 11.8, and 0.3 μg L⁻¹ in groundwater samples from swine feedlots; and 29.7, 14.0, and 0 μg L⁻¹ in groundwater samples from villages. Ordination analysis revealed that the composition and distribution of antibiotics and antibiotic resistance genes (AGRs) were similar in groundwater samples from swine feedlots and villages. FQNs and TCs occurred along the path from wastewater to groundwater at high concentrations and showed correlations with ARGs, with a strong correlation between FQN resistance gene (qnrA) copy number. FQN concentration was also found (P < 0.01) in wastewater and groundwater in villages (P < 0.01). Therefore, antibiotics discharged from swine feedlots through wastewater could disseminate into surrounding groundwater environments together with ARG occurrence (i.e., qnrA, sulI, sulII, tetG, tetM, and tetO). Overall, this study suggests that the spread of veterinary antibiotics from swine feedlots to groundwater environments should be highly attended and controlled by restricting excess antibiotic usage or improving the technology of manure management.
显示更多 [+] 显示较少 [-]Application of experimental design for the optimization of artificial neural network-based water quality model: a case study of dissolved oxygen prediction 全文
2018
Šiljić Tomić, Aleksandra | Antanasijević, Davor | Ristic, Mirjana | Perić-Grujić, Aleksandra | Pocajt, Viktor
This paper presents an application of experimental design for the optimization of artificial neural network (ANN) for the prediction of dissolved oxygen (DO) content in the Danube River. The aim of this research was to obtain a more reliable ANN model that uses fewer monitoring records, by simultaneous optimization of the following model parameters: number of monitoring sites, number of historical monitoring data (expressed in years), and number of input water quality parameters used. Box–Behnken three-factor at three levels experimental design was applied for simultaneous spatial, temporal, and input variables optimization of the ANN model. The prediction of DO was performed using a feed-forward back-propagation neural network (BPNN), while the selection of most important inputs was done off-model using multi-filter approach that combines a chi-square ranking in the first step with a correlation-based elimination in the second step. The contour plots of absolute and relative error response surfaces were utilized to determine the optimal values of design factors. From the contour plots, two BPNN models that cover entire Danube flow through Serbia are proposed: an upstream model (BPNN-UP) that covers 8 monitoring sites prior to Belgrade and uses 12 inputs measured in the 7-year period and a downstream model (BPNN-DOWN) which covers 9 monitoring sites and uses 11 input parameters measured in the 6-year period. The main difference between the two models is that BPNN-UP utilizes inputs such as BOD, P, and PO₄³⁻, which is in accordance with the fact that this model covers northern part of Serbia (Vojvodina Autonomous Province) which is well-known for agricultural production and extensive use of fertilizers. Both models have shown very good agreement between measured and predicted DO (with R² ≥ 0.86) and demonstrated that they can effectively forecast DO content in the Danube River.
显示更多 [+] 显示较少 [-]Impact of urbanization on energy intensity by adopting a new technique for regional division: evidence from China 全文
2018
Lv, Yulan | Si, Chuanning | Zhang, Shunling | Sarwar, Suleman
Using unbalanced data from 30 provinces in China between 1990 and 2015, this paper investigates the impact of urbanization on energy intensity with three control variables: economic growth, industrialization, and foreign direct investment. All the samples are divided into two sub-samples using a newly developed partially heterogeneous framework. For empirical estimations, we have used four models that deal with the homogeneous-heterogeneous slope with static-dynamic model specifications. Mainly, new estimation methods are used for dynamic models considering both heterogeneity and cross-sectional dependence. Empirical results show economic growth is a steady factor that decreases energy intensity. Urbanization and industrialization have a significant and positive relationship with energy intensity, which illustrates that higher urbanization impacts negatively on energy intensity. The influence of foreign direct investment is negative. Moreover, these findings vary across different model specifications and samples. The heterogeneous effects suggest regional specific policies across the provinces.
显示更多 [+] 显示较少 [-]Metal accumulation in the marine bivalve, Marcia optima collected from the coastal area of Phuket Bay, Thailand 全文
2018
Akkajit, Pensiri | Fajriati, Putri | Assawadithalerd, Mongkolchai
Metal contamination in seafood has raised public health concerns, especially for local residents who live in coastal areas. In this study, the levels of cadmium (Cd), lead (Pb), mercury (Hg), and zinc (Zn) were determined in the marine bivalve, Marcia optima, as well as in water, and sediment samples collected from the coastal area of Phuket Bay, Thailand. The results showed that metal concentrations in sediments (4.05–7.14, 16.68–18.13, 164–213 mg kg⁻¹ for Cd, Pb, and Zn, respectively) and water samples (0.16–0.44, 0.15–0.26, and 0.32–0.48 mg L⁻¹ for Cd, Pb, and Zn, respectively) were below the threshold effects concentration of the sediment quality guidelines for adverse effects to occur and the marine water quality standards of Thailand. A human risk assessment was performed and the results showed that the risks associated with M. optima consumption at Saphan Hin and Paklok were negligible for most of the metals studied, with the maximum estimated daily intake value being observed for Zn (0.00663 mg kg⁻¹ per day) at Saphan Hin. In addition, Cd, Zn, Pb, and Hg would be unlikely to pose a risk to human health with a hazard quotient of less than 1, with only the bioaccumulation factor of Zn being detectable in both locations (0.034 and 0.026 at Saphan Hin and Paklok, respectively). However, continuous monitoring is encouraged to prevent the risks associated with the consumption of metal-contaminated seafood.
显示更多 [+] 显示较少 [-]Flocculation performance of lignin-based flocculant during reactive blue dye removal: comparison with commercial flocculants 全文
2018
Guo, Kangying | Gao, Baoyu | Li, Ruihua | Wang, Wenyu | Yue, Qinyan | Wang, Yan
A novel lignin-based flocculant (LBF) with superior flocculation performance was prepared from paper mill sludge in this work. The functional groups of LBF and alkaline lignin (AL) were determined by Fourier transform infrared spectroscopy (FTIR). The flocculation performance of LBF integrated with polyaluminum chloride (PAC) was tested in reactive dye wastewater treatment. Floc properties and color removals in multiple flocculation systems were discussed. Results indicated that the dye removal (93%) was greatly facilitated as the LBF was integrated with PAC (PAC + LBF). In addition, floc properties and color removals were significantly improved in the presence of Ca²⁺ and Mg²⁺. In contrary, flocculation performance was greatly restricted in the presence of SO₄²⁻. LBF was less pH sensitive and shear sensitive than polyacrylamide (PAM) due to the enhanced charge neutralization and bridging action. On the basis of that, LBF could be used as a promising flocculant in dye wastewater treatment.
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