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Toxicity of three emerging contaminants to non-target marine organisms
2019
da Silva, Allyson Q. | de Souza Abessa, Denis Moledo
Coastal areas are continually impacted by anthropic activities because they shelter large urban conglomerates. Urban effluents directly or indirectly end up reaching the marine environment, releasing a large number of pollutants which include the so-called contaminants of emerging concern (CECs), since the conventional treatment plants are not effective in removing these compounds from the effluents. These substances include hormones, pharmaceuticals and personal care products, nanoparticles, biocides, among others. The aim of this study was to evaluate the toxicity of the 17α-ethinylestradiol (EE2), acetylsalicylic acid (ASA), and bisphenol-A (BPA) to two marine crustaceans and one echinoderm, evaluating the following parameters: survival (Artemia sp. and Mysidopsis juniae), embryo-larval development (Echinometra lucunter). The LC₅₀ values calculated in the acute toxicity tests showed that the compounds were more toxic to M. juniae than to the Artemia sp. Among the three contaminants, EE2 was the most toxic (LC₅₀₋₄₈ₕ = 18.4 ± 2.7 mg L⁻¹ to Artemia sp.; LC₅₀₋₉₆ₕ = 0.36 ± 0.07 mg L⁻¹ to M. juniae). The three tested compounds affected significantly the embryonic development of the sea urchin in all tested concentrations, including ecologically relevant concentrations, indicating the potential risk that these contaminants may present to the marine biota.
Afficher plus [+] Moins [-]Developing an electric vehicle urban driving cycle to study differences in energy consumption
2019
This paper develops a methodology for constructing a representative electric vehicle (EV) urban driving cycle as a basis for studying the differences in estimated energy consumption, taking Xi’an as an example. The test route is designed in accordance with the overall topological structure of the urban roads in the study region and the results of a traffic flow survey. Wavelet decomposition and reconstruction are utilized to preprocess the original data. Principal component analysis (PCA) is used to reduce the number of the kinetic parameters. The fuzzy C-means (FCM) clustering algorithm is used to cluster the driving segments. A representative EV urban driving cycle is constructed in accordance with the time proportions of three classes of driving segments and the correlation coefficients of the characteristic parameters. Finally, the differences in energy consumption estimates obtained using the constructed Xi’an EV urban driving cycle (XA-EV-UDC) and the international driving cycles are studied. The comparison shows that when international driving cycles are used to estimate the energy consumption and driving range of EVs, large relative errors will result, with energy consumption errors of 9.65 to 21.17% and driving range errors of 20.10 to 38.14%. Therefore, to accurately estimate energy consumption and driving range of EVs under real-world driving conditions, representative EV driving cycles for each typical city and region should be constructed.
Afficher plus [+] Moins [-]Hospital wastewaters treatment: Fenton reaction vs. BDDE vs. ferrate(VI)
2019
Mackuľak, Tomáš | Grabic, Roman | Špalková, Viera | Belišová, Noemi | Škulcová, Andrea | Slavík, Ondřej | Horký, Pavel | Gál, Miroslav | Filip, Jan | Híveš, Ján | Vojs, Marian | Staňová, Andrea Vojs | Medveďová, Alžbeta | Marton, Marián | Birošová, Lucia
Various types of micropollutants, e.g., pharmaceuticals and their metabolites and resistant strains of pathogenic microorganisms, are usually found in hospital wastewaters. The aim of this paper was to study the presence of 74 frequently used pharmaceuticals, legal and illegal drugs, and antibiotic-resistant bacteria in 5 hospital wastewaters in Slovakia and Czechia and to compare the efficiency of several advanced oxidations processes (AOPs) for sanitation and treatment of such highly polluted wastewaters. The occurrence of micropollutants and antibiotic-resistant bacteria was investigated by in-line SPE-LC-MS/MS technique and cultivation on antibiotic and antibiotic-free selective diagnostic media, respectively. The highest maximum concentrations were found for cotinine (6700 ng/L), bisoprolol (5200 ng/L), metoprolol (2600 ng/L), tramadol (2400 ng/L), sulfamethoxazole (1500 ng/L), and ranitidine (1400 ng/L). In the second part of the study, different advanced oxidation processes, modified Fenton reaction, ferrate(VI), and oxidation by boron-doped diamond electrode were tested in order to eliminate the abovementioned pollutants. Obtained results indicate that the modified Fenton reaction and application of boron-doped diamond electrode were able to eliminate almost the whole spectrum of selected micropollutants with efficiency higher than 90%. All studied methods achieved complete removal of the antibiotic-resistant bacteria present in hospital wastewaters.
Afficher plus [+] Moins [-]Characterization of chemical components and cytotoxicity effects of indoor and outdoor fine particulate matter (PM2.5) in Xi’an, China
2019
Niu, Xinyi | Ho, Kin Fai | Hu, Tafeng | Sun, Jian | Duan, Jing | Huang, Yu | Lui, Ka Hei | Cao, Junji
The chemical and cytotoxicity properties of fine particulate matter (PM₂.₅) at indoor and outdoor environment were characterized in Xi’an, China. The mass concentrations of PM₂.₅ in urban areas (93.29~96.13 μg m⁻³ for indoor and 124.37~154.52 μg m⁻³ for outdoor) were higher than suburban (68.40 μg m⁻³ for indoor and 96.18 μg m⁻³ for outdoor). The PM₂.₅ concentrations from outdoor environment due to fossil fuel combustion were higher than indoor environment. An indoor environment without central heating demonstrated higher organic carbon-to-elemental carbon (OC / EC) ratios and n-alkanes values that potentially attributed to residential coal combustion activities. The cell viability of human epithelial lung cells showed dose-dependent decrease, while nitric oxide (NO) and oxidative potential showed dose-dependent increase under exposure to PM₂.₅. The variations of bioreactivities could be possibly related to different chemical components from different sources. Moderate (0.4 < R < 0.6) to strong (R > 0.6) correlations were observed between bioreactivities and elemental carbon (EC)/secondary aerosols (NO₃⁻, SO₄²⁻, and NH₄⁺)/heavy metals (Ni, Cu, and Pb). The findings suggest PM₂.₅ is associated with particle induced oxidative potential, which are further responsible for respiratory diseases under chronic exposure.
Afficher plus [+] Moins [-]Preparation of a novel nano-Fe3O4/triethanolamine/GO composites to enhance Pb2+/Cu2+ ions removal
2019
In this paper, a magnetic nano-Fe₃O₄/triethanolamine/GO composite (TEA-GO-FE) was prepared by using graphene oxide (GO), triethanolamine (TEA), and ferric chloride. The result indicates that triethanolamine acted as an important role for the growing of Fe₃O₄ and adsorption ability of composite material. The synthesis mechanism of TEA-GO-FE was investigated through the medium of SEM-EDS, XRD, FT-IR, and TEM. The characterization results indicated Fe₃O₄ nanoparticles have been successfully loaded on the surface of graphene oxide and they were encapsulated by TEA and have excellent stability. According to the results of XRD, the general particle size of Fe₃O₄ on TEA-GO-FE was 27.5 nm. In order to understand the adsorption properties of TEA-GO-FE for Pb²⁺ and Cu²⁺, this article uses a static adsorption study method. The optimized adsorption conditions are as follows: pH = 5.0, temperature is 293.15 K, and the ion concentration is 100 mg/L. Under the optimized prerequisites, the adsorption capacities of Pb²⁺ and Cu²⁺ were 121.5 mg/g and 68.7 mg/g, separately. Through thermodynamic as well as kinetic studies, the adsorption process of Pb²⁺ and Cu²⁺ on TEA-GO-FE is a self-heating process.
Afficher plus [+] Moins [-]Efficacy of two actinomycete extracts in the amelioration of carbon tetrachloride–induced oxidative stress and nephrotoxicity in experimental rats
2019
Actinomycetes are a group of the Gram-positive bacteria famous for their antimicrobial, anticancer, anti-parasitic, and anti-inflammatory activities. This study aimed to investigate the efficacy of two bacterial extracts derived from two soil actinomycete strains (S19 and G30) against carbon tetrachloride (CCl₄)–induced nephrotoxicity in experimental rats. Sixty-four male rats were assigned to four groups of 16 rats in each group. The 1st group was kept as a normal (control) group and given corn oil combined with the used production medium, while the 2nd group received only CCl₄ (CCl₄ group). On the other hand, the 3rd group (CCl₄+S19) was administered CCl₄ and the extract of the actinomycete strain S19 and the 4th group (CCl₄+G30) received CCl₄ and the extract of the actinomycete strain G30, both treatments for 8 weeks. The results revealed that the two actinomycete extracts S19 and G30 could significantly (p < 0.01) lower the elevated levels of serum creatinine, urea, and uric acid caused by the CCl₄ administration. Additionally, the two actinomycete extracts improved the decreased serum total protein. Interestingly, treatment of the CCl₄-intoxicated rats with S19 and G30 extracts remarkably reversed the lowered renal glutathione (GSH), glutathione peroxidase (GSH-Px), peroxidase (Px) and superoxide dismutase (SOD) activities, and the elevated lipid peroxidation (LPO) levels. The histopathological examination of the treated kidney revealed that the two actinomycete extracts improved rats against CCl₄-induced kidney lesions. The present results suggested that the protective effect of the two actinomycete extracts may rely on its effect on reducing the oxidative stress and improving the antioxidant defense system.
Afficher plus [+] Moins [-]Arsenic removal by copper-impregnated natural mineral tufa part II: a kinetics and column adsorption study
2019
This batch and column kinetics study of arsenic removal utilized copper-impregnated natural mineral tufa (T–Cu(A–C)) under three ranges of particle size. Non-competitive kinetic data fitted by the Weber–Morris model and the single resistance mass transfer model, i.e., mass transfer coefficient kfa and diffusion coefficient (Dₑff) determination, defined intra-particle diffusion as the dominating rate controlling step. Kinetic activation parameters, derived from pseudo-second-order rate constants, showed low dependence on adsorbent geometry/morphology and porosity, while the diffusivity of the pores was significant to removal efficacy. The results of competitive arsenic adsorption in a multi-component system of phosphate, chromate, or silicate showed effective arsenic removal using T–Cu adsorbents. The high adsorption rate—pseudo-second-order constants in the range 0.509–0.789 g mg⁻¹ min⁻¹ for As(V) and 0.304–0.532 g mg¹ min¹ for As(III)—justified further application T–Cu(A–C) in a flow system. The fixed-bed column adsorption data was fitted using empirical Bohart–Adams, Yoon–Nelson, Thomas, and dose–response models to indicate capacities and breakthrough time dependence on arsenic influent concentration and the flow rate. Pore surface diffusion modeling (PSDM), following bed-column testing, further determined adsorbent capacities and mass transport under applied hydraulic loading rates.
Afficher plus [+] Moins [-]Metals in wild fish from Gaotang Lake in the area of coal mining, China: assessment of the risk to human health
2019
Environmental pollution can cause metal accumulation in aquatic organisms, but information on metal bioaccumulation in wild fish from coal mining areas is limited. We investigated tissue-specific metal accumulation in six economically important fish species common to Gaotang Lake, China, located in a coal mining area. We also conducted an assessment of potential risks to human health from consumption of these fish. Mean concentrations of arsenic, cadmium, cobalt, copper, mercury, lead, and antimony in the muscle of six fish species were below the corresponding Chinese maximum allowable concentrations except chromium and generally comparable with levels in fish reported by other studies. Tissue distribution patterns suggested that chromium and mercury were easily transported to the muscle, but concentrations of the other six metals were higher in the liver and gills. The daily intake of each metal was estimated at 0.002–0.220 g/day/kg body weight, and the non-carcinogenic health risks associated with the consumption of the fish from Gaotang Lake were acceptable. The results suggest that metal bioaccumulation in wild fish is not high in this coal mining area.
Afficher plus [+] Moins [-]Study on the influence of surface potential on the nitrate adsorption capacity of metal modified biochar
2019
Carbon materials, as effective adsorbents to numerous aqueous cationic contaminants, have been hardly applied to remove anions in wastewater. In this work, different modifying agents were used to modify corncob biochars (CC) and the surface potentials of these modified biochars were determined. Based on the findings, modification principle was determined to reveal the relationship between surface potentials of the biochars and their nitrate adsorption capacities. The surface potential was dominated by the metal cations and multivalent cations led to even positive zeta potential. The formation of metal oxide not only led to the augment in surface area but also increase the surface charge. FeCl₃-modified biochar (Fe-CC) with the highest positive surface charge was utilized to remove anions (nitrate) from aqueous solutions. Characterization results confirm that Fe₂O₃ structure were successfully formed on biochar surface. This led to the formation of iron nitrate hydrate (Fe(NO₃)₃·9H₂O), which enabled higher nitrate adsorption performance than that of pristine biochar. Batch experiments showed that nitrate adsorption on the Fe-CC was stable and almost independent of experimental pH and temperature. Based on the Langmuir model results, the maximum nitrate adsorption capacity of Fe-CC was 32.33 mg/g. Coexisting anions had negative influence on the adsorption performance. Findings of this work suggest that the modified biochar can be used in wastewater treatment to remove anions such as nitrate. Graphic abstract ᅟ
Afficher plus [+] Moins [-]Sequential determination and chemical speciation analysis of inorganic As and Sb in airborne particulate matter collected in outdoor and indoor environments using slurry sampling and detection by HG AAS
2019
In this work, fast sequential determination and chemical speciation analysis of inorganic arsenic and antimony in airborne particulate matter collected in outdoor and indoor environments using slurry sampling and detection by hydride generation atomic absorption spectrometry (HG-AAS) is proposed. A Doehlert design was applied to optimise the hydride generation conditions of As and Sb for fast sequential determination in the same aliquot of particulate matter samples after preparation of the slurry. The limits of quantification (LoQ) obtained for As and Sb were 0.3 and 0.9 ng m⁻³, respectively. The accuracy of the analytical method was confirmed by analysis of the certified reference material of urban particulate matter (SRM NIST 1648a), presenting concordance with certified values of 92.7±7.7% for As and 91.2±9.5% for Sb. Precision was expressed as relative standard deviation (% RSD, n=3), with our results presenting values better than 3.4% and 4.2% for total inorganic As and Sb, respectively. For all analysed samples, total As concentrations and its inorganic species were below the LoQ of the analytical method (<0.3 ng m⁻³). However, the averages of total inorganic Sb concentrations in airborne particulate matter, collected as total suspended outdoor particles (TSPₒᵤₜdₒₒᵣ), inhalable particulate matter (PM₁₀), and total suspended indoor particles (TSPᵢₙdₒₒᵣ), were 3.1±0.5, 2.4±0.6, and 2.6±0.4 ng m⁻³, respectively. Trivalent Sb (Sb³⁺) was the predominant inorganic species in all samples investigated, with mean percentages of 76%, 72%, and 73% in TSPₒᵤₜdₒₒᵣ, PM₁₀, and TSPᵢₙdₒₒᵣ, respectively. The presence of Sb and its predominant inorganic form (Sb³⁺) can be attributed to vehicular traffic close to the sampled urban areas. Therefore, fast sequential determination of As and Sb and their inorganic species in particulate matter samples prepared as slurry by FS-HG-AAS is an efficient, accurate, and precise method and can be successfully applied to routine analysis.
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