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Public health risk of heavy metal residues in meat and edible organs of broiler in an intensive production system of a region in Pakistan
2019
ʻAbbās, Muḥammad | Chand, Naila | Khan, Rifat Ullah | Aḥmad, Naz̲īr | Pervez, Urooba | Naz, Shabana
The aim of this study was to find the concentration of lead (Pb), cadmium (Cd), nickel (Ni), manganese (Mn), and zinc (Zn) in feed, drinking water, and their residues in meat and internal organs in broilers at three different locations in Charsadda. For this purpose, a total of 48 representative water and feed samples and 240 meat and internal organs of broilers were collected. Significantly (P < 0.05) higher concentrations of Zn and Mn were found in feed samples. In water samples assessed for heavy metals, a significantly (P < 0.05) higher concentration of Pb was observed at Umerabad and Kula Dher as compared with Nisatta whereas a significantly (P < 0.05) higher concentration of Ni was recorded at Umerabad as compared with Nisatta and Kula Dher. Similarly, a significantly (P < 0.05) higher concentration of Mn in water was recorded at Kula Dher as compared with Nisatta and Umerabad. The concentration of Pb in water at all locations and the concentration of Ni at Umerabad were above the maximum permissible limits. A significantly (P < 0.05) higher concentration of Pb in the liver, breast, and thigh muscles and a significantly (P < 0.05) higher concentration of Mn in the liver, gizzard, breast, and thigh muscles of broilers were recorded at Kula Dher. A significantly (P < 0.05) higher mean concentration of Pb, Cd, Ni, Mn, and Zn was recorded in the liver as compared with the gizzard, breast, and thigh muscles. It was concluded from the present study that broiler farms near the roadside/canal and waste disposal site/wastewater drains cause accomulaiton of high concentrations of some heavy metals in meat and internal organs of broiler birds.
Показать больше [+] Меньше [-]Magnetic Fe3O4/multi-walled carbon nanotubes materials for a highly efficient depletion of diclofenac by catalytic wet peroxideoxidation
2019
Huaccallo, Ysabel | Álvarez-Torrellas, Silvia | Marín, María Pilar | Gil, María Victoria | Larriba, Marcos | Águeda, Vicente Ismael | Ovejero, Gabriel | Garcia, Juan
The aim of this work is to synthesize a magnetic magnetite/multi-walled carbon nanotube (Fe₃O₄/MWCNT) catalyst by a method combining co-precipitation and hydrothermal treatments for the efficient removal of diclofenac (DCF) by catalytic wet peroxide oxidation (CWPO). The support (MWCNTs) shows a moderate-large surface area and good adsorption capacity, leading to the improvement of the magnetite (Fe₃O₄) dispersion on its surface. The response surface methodology (RSM) was applied in order to find out the effect of the reaction parameters on DCF removal, allowing to establish the optimum operating conditions (T = 60 °C, [H₂O₂]₀ = 2.7 mM, [catalyst] = 1.0 g L⁻¹). The optimum CWPO experiment showed an outstanding catalytic activity at non-modified pH solution (6.7), obtaining a 95% of DCF removal after 3 h reaction time; this high efficiency can be attributed to the synergistic effect of the iron-based catalyst with the high quantity of •OH radicals generated on the surface of the catalyst. In addition, the Fe₃O₄/MWCNT material exhibited good reusability along three consecutive reaction cycles, finding a pollutant removal close to 95% in each cycle of 3 h reaction time. Additionally, a degradation mechanism pathway was proposed for the removal of DCF by CWPO. The versatility of the material was finally demonstrated in the treatment of different environmentally relevant aqueous matrices (a wastewater treatment plant effluent, surface water, and hospital wastewater), obtaining an effective reduction in the ecotoxicity values.
Показать больше [+] Меньше [-]Shaddock peels-based activated carbon as cost-saving adsorbents for efficient removal of Cr (VI) and methyl orange
2019
Tao, Xiaoming | Wu, Yunhai | Cha, Ligen
A simple and economical method was proposed to synthesize the shaddock peels-based activated carbon (SPAC) for their application as efficient sorbents to eliminate Cr (VI) and methyl orange (MO) from one-component and two-component systems. The synthesis was conducted via activation of phosphoric acid and high-temperature carbonization. The as-prepared SPAC was characterized by Brunauer–Emmett–Teller, scanning electron microscopy, energy dispersive X-ray spectroscopy, thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy, among other techniques. The adsorption experiment, which used five types of fruit peel (shaddock peels, orange peels, apple peels, banana peels, and tangerine peels), indicated that shaddock peels were the optimal precursors, with the high removal efficiencies for Cr (VI) (21.2%) and MO (54.25%). The effects of various factors (e.g., initial concentration, sorbent dosage, pH values, and contact time) were systematically evaluated. For the one-component system, the maximum adsorption capacities of Cr (VI) (9.95 mg/g) and MO (94.59 mg/g) reached pH levels 2 and 3, respectively. Kinetic modeling demonstrated that the pseudo-second-order kinetic model was adopted for the one-component and two-component systems. Isotherm studies suggested that Cr (VI) and MO sorption processes in the one-component explained well the Langmuir and Freundlich models, respectively. The extended Freundlich multicomponent isotherm model was more compatible for explaining competitive adsorption in the binary component system. The adsorbed amount of Cr (VI) was markedly suppressed by MO, whereas MO adsorption was not significantly influenced owing to the existence of Cr (VI). The higher adsorption capacity of MO could be mainly attributed to the strong force acting between MO and SPAC. The findings of this study confirmed that SPAC provided a sustainable choice for cycling solid waste shaddock peels to remove hazardous contaminants.
Показать больше [+] Меньше [-]Geochemical distribution of major and trace elements in agricultural soils of Castilla-La Mancha (central Spain): finding criteria for baselines and delimiting regional anomalies
2019
Bravo, Sandra | García-Ordiales, Efrén | García-Navarro, Francisco Jesús | Amorós, José Ángel | Pérez-de-los-Reyes, Caridad | Jiménez Ballesta, R. (Raimundo) | Esbrí, José María | García-Noguero, Eva María | Higueras, Pablo
Castilla-La Mancha (central Spain) is a region characterized by significant agricultural production aimed at high-quality food products such as wine and olive oil. The quality of agricultural products depends directly on the soil quality. Soil geochemistry, including dispersion maps and the recognition of baselines and anomalies of various origins, is the most important tool to assess soil quality. With this objective, 200 soil samples were taken from agricultural areas distributed among the different geological domains present in the region. Analysis of these samples included evaluation of edaphological parameters (reactivity, electrical conductivity, organic matter content) and the geochemistry of major and trace elements by X-ray fluorescence. The dataset obtained was statistically analyzed for major elements and, in the case of trace elements, was normalized with respect to Al and analyzed using the relative cumulative frequency (RCF) distribution method. Furthermore, the geographic distribution of analytical data was characterized and analyzed using the kriging technique, with a correspondence found between major and trace elements in the different geologic domains of the region as well as with the most important mining areas. The results show an influence of the clay fraction present in the soil, which acts as a repository for trace elements. On the basis of the results, of the possible elements related with clay that could be used for normalization, Al was selected as the most suitable, followed by Fe, Mn, and Ti. Reference values estimated using this methodology were lower than those estimated in previous studies.
Показать больше [+] Меньше [-]Three-dimensional batch electrochemical coagulation (ECC) of health care facility wastewater—clean water reclamation
2019
Singh, Sujit | Mahesh, Shivaswamy | Sahana, Mahesh
Three-dimensional (3D) batch ECC of raw health care facility wastewater (HCFWW) was adopted using stainless steel (SS) and aluminum (Al) scrap metal particle electrodes. ECC treatment was focused on priority quality parameters viz., chemical oxygen demand (COD), color, and other important water quality parameters. Sludge settling and filterability for post-ECC slurry were investigated after ECC. COD removals of 87.56 and 87.2% were achieved for current densities (CD) 83.33 and 125 A/m² using SS-3D electrodes, and similarly, 86.99 and 86.23% COD removal for Al-3D electrodes. Simultaneously, color removals were 88.50 and 87.60% for CD 166.66 A/m² (4A) using SS and Al-3D electrodes. Water quality parameters viz., nitrate, phosphates, and sulfate were also removed by 93.18%, 96.83%, and 41.07% for SS-3D electrodes, while Al-3D electrodes showed 93.15%, 96.72%, and 25.94% removal. Post-ECC slurry settling was good for all the applied CD using SS-3D electrodes generating dense and sturdy flocs. Al-3D electrodes showed excellent floc settling properties. SS-3D electrode flocs displayed good filterability at 1A with α: 2.497 × 10¹¹ m kg⁻¹ and Rₘ 1.946 × 10¹⁰ m⁻¹. Post-ECC slurry using Al-3D electrodes were viscous causing delayed filterability giving α: 1.1760 × 10¹¹ m kg⁻¹ and Rₘ 1.504 × 10⁹ m⁻¹ for 3A. E. coli was destroyed by 97 and 98% for 2A and 3A respectively. Clear water reclamation of 85–90% and pollutants/contaminants removed within a short HRT of 75 min proved the effectiveness of adopting 3D-ECC for treating raw HCFWW.
Показать больше [+] Меньше [-]Introduction of hydrogen fuel cell vehicles: prospects and challenges for Malaysia’s transition to a low-carbon economy
2019
Al-Amin, Abul Quasem | Doberstein, Brent
Alternative energy policies targeting the adoption of hydrogen fuel cell vehicles (HFCVs) could have significant positive impacts on Malaysia’s ability to meet both its carbon reduction goal and its energy security needs. The transport sector generally contributes heavily to carbon emissions, and is also difficult to decarbonize because of the costs associated with many greener options. This study explores the possibility of decarbonizing the Malaysian transport sector by promoting the use of hydrogen vehicles, and analyzes the adoption challenges and economic obstacles (especially public acceptance) associated with introducing HFCVs. This study contends that the adoption challenges of this new technology can be overcome through the use of development strategies outlined. This study also addresses the regulatory framework that Malaysia (and other countries) might use to overcome common policy adoption challenges of HFCVs.
Показать больше [+] Меньше [-]Removal of particulate matter and trace elements from ambient air by urban greenery in the winter season
2019
Przybysz, Arkadiusz | Nersisyan, Gayane | Gawroński, Stanisław Waldemar
Particulate matter (PM) is one of the most harmful inhaled pollutants. When PM is emitted into the atmosphere, the only possible method for cleaning ambient air is through vegetation acting as biological filters for pollutants. However, in winter periods when the concentration of PM is usually the highest, the efficiency of plants is very low. The aim of this work was therefore to examine the accumulation of PM and selected trace elements (TE) by three species, evergreen coniferous Taxus baccata L. and Pinus nigra Arn., and deciduous Carpinus betulus L. during the winter season. The highest amounts of PM accumulated on the foliage of P. nigra, while TE on the leaves of C. betulus. Most of the PM accumulated on plant foliage belonged to the large fraction size (10–100 μm) and was deposited on the surface of foliage (SPM). The concentration of four TE (Ni, Pb, Cd, and Sb) was higher in PM accumulated on foliage, while in the case of three other TE (Zn, Cr and Mg), their concentration was higher in plant tissue. The TE were recorded in all PM size fractions and were rather equally distributed between surface PM (SPM) and in-wax PM (WPM). These findings have implications for urban plantings in countries with short vegetative season, where tolerant conifer species and deciduous species which keep foliage through winter should be included in urban forest plantings due to their efficiency in the removal of pollutants from the air.
Показать больше [+] Меньше [-]Developing air exchange rate models by evaluating vehicle in-cabin air pollutant exposures in a highway and tunnel setting: case study of Tehran, Iran
2019
Nayeb Yazdi, Mohammad | Arhami, Mohammad | Delavarrafiee, Maryam | Ketabchy, Mehdi
The passengers inside vehicles could be exposed to high levels of air pollutants particularly while driving on highly polluted and congested traffic roadways. In order to study such exposure levels and its relation to the cabin ventilation condition, a monitoring campaign was conducted to measure the levels inside the three most common types of vehicles in Tehran, Iran (a highly air polluted megacity). In this regard, carbon monoxide (CO) and particulate matter (PM) were measured for various ventilation settings, window positions, and vehicle speeds while driving on the Resalat Highway and through the Resalat Tunnel. Results showed on average in-cabin exposure to particle number and PM₁₀ for the open windows condition was seven times greater when compared to closed windows and air conditioning on. When the vehicle was passing through the tunnel, in-cabin CO and particle number increased 100 and 30%, respectively, compared to driving on highway. Air exchange rate (AER) is a significant factor when evaluating in-cabin air pollutants level. AER was measured and simulated by a model developed through a Monte Carlo analysis of uncertainty and considering two main affecting variables, vehicle speed and fan speed. The lowest AER was 7 h⁻¹ for the closed window and AC on conditions, whereas the highest AER was measured 70 h⁻¹ for an open window condition and speed of 90 km h⁻¹. The results of our study can assist policy makers in controlling in-cabin pollutant exposure and in planning effective strategies for the protection of public health.
Показать больше [+] Меньше [-]Production, characterization and effectiveness of cellulose acetate functionalized ZnO nanocomposite adsorbent for the removal of Se (VI) ions from aqueous media
2019
Gurunathan, Padmalaya | Hari, Sivaram | Suseela, Sreeja Balakrishnapillai | Sankararajan, Radha | Mukannan, Arivanandan
In this study, ZnO functionalized cellulose acetate nanocomposite (ZnO/CA NC) was synthesized using a simple chemical approach found to have a high surface area of 657.34 m²/g and utilized as adsorbents for the removal of Se (VI) from aqueous solutions. Investigations on X-ray diffraction (XRD) revealed that ZnO nanocomposite has a smaller crystallite size compared to ZnO nanoparticles which facilitated for reduced agglomeration confirmed by scanning electron microscopy (SEM). The ensuing properties of ZnO/CA NC displayed high maximum adsorption capacity of 160.5 mg/g for Se (VI) ions. Inner-sphere surface complexes on ZnO/CA NC under prevailing conditions for Se (VI) were discussed using FTIR spectroscopical results. In order to evaluate the removal efficiency, the effects of adsorbent dosage, pH, and temperature were thoroughly investigated. The amount of Se (VI) ions adsorbed on ZnO/CA NC was also determined by zeta potential. The fractional removal of pollutants (Se (VI)) was done using mass transfer model. In addition, prominent adsorption capacity was also tested utilizing concurrent anions (SO₄²⁻, Cl⁻, and F⁻) with reference to Se (VI) and cost prudent regenerability of adsorbent by NaOH solution was ascertained with anti-interference and recovery steps. ZnO/CA NC was obtained by simple chemical methodology and high surface adsorption capacities supply an encouraging technique for Se (VI) removal in water treatment applications.
Показать больше [+] Меньше [-]Enhanced inactivation of antibiotic-resistant bacteria isolated from secondary effluents by g-C3N4 photocatalysis
2019
Ding, Ning | Chang, Xueming | Shi, Na | Yin, Xiufeng | Qi, Fei | Sun, Yingxue
The extensive use of antibiotics has resulted in the development of antibiotic-resistant bacteria (ARB), which may not be completely removed by traditional wastewater treatment processes. More effective approaches to disinfection are needed to prevent the release of ARB into the surface water. The metal-free photocatalyst graphitic carbon nitride (g-C₃N₄) has aroused great interest as a possible agent for water and wastewater treatment, due to its low cytotoxicity and photoactivity with visible light. In this study, the efficacy of g-C₃N₄ was assessed as a possible means to enhance ARB inactivation by irradiation. ARB were isolated and purified from secondary effluents in 4 municipal wastewater treatment plants. Of these, 4 typical multi-drug ARB isolates, belonging to Enterobacteriaceae, were selected for irradiation experiments. Inactivation was seen to increase with irradiation time. At 60 min, the inactivation of the 4 ARB isolates by light at > 300 nm and > 400 nm was in the range of 0.25–0.39 log and 0.16–0.19 log, respectively. The use of g-C₃N₄-mediated photocatalysis at the same wavelengths significantly enhanced that to 0.64–1.26 log and 0.31–0.41 log, respectively. The antibiotic susceptibility of the ARB isolates remained unchanged either prior to or after irradiation and was independent of photon fluence, reaction time, and the presence of g-C₃N₄. This study establishes a baseline for understanding the effectiveness of g-C₃N₄ photocatalysis on inactivation of ARB in wastewaters and lays the foundation for further improvement in the use of photocatalysis for wastewater treatment.
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