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Resultados 4841-4850 de 4,924
Microarray analysis of apoptosis gene expression in liver injury induced by chronic exposure to arsenic and high-fat diet in male mice Texto completo
2019
Kalantari, Heibatullah | Khodayar, Mohammad Javad | Saki, Najmaldin | Khorsandi, Layasadat | Teymoori, Ali | Alidadi, Hadis | Samimi, Azin
Rapid growth in the incidence of liver disease is largely attributable to lifestyle and environmental contaminants, which are often overlooked as the leading causes of this problem. Thus, the possible contribution of arsenic (As) to high-fat diet (HFD)–induced liver damage was examined via microarray analysis. To perform this experiment, a total number of 40 healthy adult male NMRI mice (22–30 g) were used. To this end, these animals were randomly assigned to four groups of 10. Oxidative stress and histopathological parameters were also evaluated in the liver of the mice exposed to a minimally cytotoxic concentration of As (50 ppm) in drinking water while being fed with a HFD for 20 weeks. Subsequently, apoptosis gene expression profiling was utilized via real-time (RT) PCR array analysis. The results showed that As had increased the amount of HFD-induced liver damage and consequently amplified changes in oxidative stress factors, histopathological parameters, as well as apoptosis pathway genes. Investigating the expression profile of apoptosis pathway genes similarly revealed that caspase-8, as a main upstream contributor to the apoptosis pathway, might play an important role in the induction of apoptosis generated by As and HFD. Ultimately, this study highlighted that As in drinking water could increase sensitivity in mice to HFD-induced liver disease through strengthening apoptosis pathway.
Mostrar más [+] Menos [-]Organic micropollutants’ distribution within sludge organic matter fractions explains their dynamic during sewage sludge anaerobic digestion followed by composting Texto completo
2019
Aemig, Quentin | Doussiet, Nicolas | Danel, Alice | Delgenès, Nadine | Jimenez, Julie | Houot, Sabine | Patureau, Dominique
The simultaneous fate of organic matter and 4 endocrine disruptors (3 polycyclic aromatic hydrocarbons (PAHs) (fluoranthene, benzo(b)fluoranthene, and benzo(a)pyrene) and nonylphenols (NP)) was studied during the anaerobic digestion followed by composting of sludge at lab-scale. Sludge organic matter was characterized, thanks to chemical fractionation and 3D fluorescence deciphering its accessibility and biodegradability. Total chemical oxygen demand (COD) removal was 41% and 56% during anaerobic digestion and composting, respectively. 3D fluorescence highlighted the quality changes of organic matter. During continuous anaerobic digestion, organic micropollutants’ removal was 22 ± 14%, 6 ± 5%, 18 ± 9%, and 0% for fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, and nonylphenols, respectively. Discontinuous composting allowed to go further on the organic micropollutants’ removal as 34 ± 8%, 31 ± 20%, 38 ± 10%, and 52 ± 6% of fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, and nonylphenols were dissipated, respectively. Moreover, the accessibility of PAH and NP expressed by their presence in the various sludge organic matter fractions and its evolution during both treatments was linked to both the quality evolution of the organic matter and the physicochemical properties of the PAH and NP; the presence in most accessible fractions explained the amount of PAH and NP dissipated.
Mostrar más [+] Menos [-]Risk assessment of groundwater environmental contamination: a case study of a karst site for the construction of a fossil power plant Texto completo
2019
Liu, Fuming | Yi, Shuping | Ma, Haiyi | Huang, Junyi | Tang, Yukun | Qin, Jianbo | Zhou, Wan-huan
This paper presents a demonstration of an integrated risk assessment and site investigation for groundwater contamination through a case study, in which the geologic and hydrogeological feature of the site and the blueprint of the fossil power plant (FPP) were closely analyzed. Predictions for groundwater contamination in case of accidents were performed by groundwater modeling system (GMS) and modular three-dimensional multispecies transport model (MT3DMS). Results indicate that the studied site area presents a semi-isolated hydrogeological unit with multiplicity in stratum lithology, the main aquifers at the site are consisted of the filled karst development layer with a thickness between 6.0 and 40.0 m. The poor permeability of the vadose zone at the FPP significantly restricted the infiltration of contaminants through the vadose zone to the subsurface. The limited influence of rarely isotropic porous karstified carbonate rocks on the groundwater flow system premised the simulate scenarios of plume migration. Analysis of the present groundwater chemistry manifested that that the groundwater at the site and the local area are of the HCO₃–Ca, HCO₃, and SO₄–Ca types. A few of the water samples were contaminated by coliform bacteria and ammonia nitrogen as a result of the local cultivation. Prediction results indicate that the impact of normal construction and operation processes on the groundwater environment is negligible. However, groundwater may be partly contaminated within a certain period in the area of leakage from the diesel tanks, the industrial wastewater pool, and the cooling tower water tank in case of accidents. On a positive note, none of the plumes would reach the local sensitive areas for groundwater using. Finally, an anti-seepage scheme and a monitoring program are proposed to safeguard the groundwater protection. The integrated method of the site investigation and risk assessment used in this case study can facilitate the protection of groundwater for the construction of large-scale industrial project.
Mostrar más [+] Menos [-]The efficacy and cytotoxicity of iron oxide-carbon black composites for liquid-phase toluene oxidation by persulfate Texto completo
2019
Dong, Cheng-Di | Chen, Chiu-Wen | Tsai, Mei-Ling | Hung, Chang-Mao
This study evaluated the oxidation of toluene (TOL) by persulfate (PS) in aqueous solution in the presence of a Fe₃O₄-carbon black (CB) composite oxidant system generating sulfate radicals. The cytotoxic activity and oxidative stress generated by these materials were investigated in rat liver Clone 9 cells. The effects of various operating parameters including the pH and concentrations of PS, Fe₃O₄-CB, and TOL were evaluated to optimize the oxidation process. The results showed that Fe₃O₄-CB/PS achieved effective removal of TOL under acidic conditions. The TOL degradation efficiency was strongly pH-dependent, where pH 3.0 > 6.0 > 9.0. Additionally, the viability of Clone 9 cells exposed to 0–400 μg/mL Fe₃O₄-CB indicated that this material showed low cytotoxicity. A dichlorodihydrofluorescein diacetate assay performed to evaluate the generation of reactive oxygen species indicated that Fe₃O₄ showed relatively lower toxicity than CB in these cells. Therefore, the cytotoxicity of CB may involve the induction of oxidative stress and physical changes in cell morphology.
Mostrar más [+] Menos [-]Preparation of PVA/tetra-ZnO composite with framework-supported pore-channel structure and the removal research of lead ions Texto completo
2019
Xu, Sheng | Jiang, Xinde | Liu, Lingli | Wang, Zhenxi | Zhang, Xiaohang | Peng, Yong | Cao, Meng
Polyvinyl alcohol (PVA) filled with different kinds of ZnO whisker was prepared by chemical cross-linking reaction. It was found that the ZnO whiskers dispersed uniformly after being modified by 3-aminopropyltriethoxysilane (APTES). The PVA/tetrapod-shaped ZnO (PVA/tetra-ZnO) composites showed better adsorption performance than other kinds of PVA/ZnO composites. The framework-supported pore-channel structure was beneficial for the transmission and adsorption of heavy metal ions, and the formation of “brush” pore-channel of PVA/tetra-ZnO composites can effectively retain and capture the heavy metal ions. The PVA/tetra-ZnO composites presented well adsorption on Pb(II), Cd(II), and Cr(III) ions than Ni(II) and showed relatively selective removal on Pb(II) and Cr(III) ions. The adsorbed heavy metal ions presented gradient distribution with high content in the out layer and low content in the inner layer. Pb(II) adsorption capacity qₑ increased gradually with the increase of initial solution concentration and contact time which tended to be stable at 400 mg/L and 800 min. The maximal adsorption capacity qₘ obtained by nonlinear fitting reached to about 116 mg/g which was very close to the experiment data. Adsorption isotherm results indicated the monolayer adsorption process of the Langmuir model and the adsorption kinetics data fitted well to the pseudo-second-order model. The adsorption process was spontaneous and the high temperature was in favor of adsorption. The adsorption mechanism was explored as the combination of coordination and ion exchange. Besides, the PVA/tetra-ZnO composites exhibited better stress stability, thermo stability, and favorable regeneration than neat PVA.
Mostrar más [+] Menos [-]Hydrothermal carbonisation of peat-based spent sorbents loaded with metal(loid)s Texto completo
2019
Kasiuliene, Alfreda | Carabante, Ivan | Bhattacharya, Prosun | Kumpiene, Jurate
Hydrothermal carbonisation (HTC) is a wet and relatively low-temperature process where, under autogenous pressures, biomass undergoes a chain of reactions leading to the defragmentation of organic matter. As well as its other uses (e.g. for producing low-cost carbon-based nano-compounds), HTC is utilised for the treatment of wet wastes, such as manure and biosludge. This study aimed to determine if hydrothermal carbonisation is a feasible treatment method for spent sorbents that are highly enriched with arsenic, chromium, copper, and zinc. The chemical properties of hydrochar and process liquid were evaluated after HTC treatment, where peat-based spent sorbents were carbonised at 230 °C for 3 h. Analysis of Fourier transform-infrared spectra revealed that during HTC, the oxygenated bonds of ethers, esters, and carboxylic groups were cleaved, and low-molecular-weight organic fragments were dissolved in the process liquid. A large fraction of arsenic (up to 62%), copper (up to 25%), and zinc (up to 36%) were transferred from the solids into the process water. Leaching of these elements from the hydrochars increased significantly in comparison with the spent sorbents.
Mostrar más [+] Menos [-]Tracing controlling factors of riverine chemistry in a headwater tributary of the Yangtze River, China, inferred from geochemical and stable isotopic signatures Texto completo
2019
Herath, Imali Kaushalya | Wu, Sheng Jun | Ma, Mao Hua | Jianli, Wang | Chandrajith, Rohana
The Jialing River is the second largest headwater tributary of the Yangtze River in China, therefore, the river water has been contaminated and water quality is deteriorated. Hence, this study aims to find the main controling factors of riverine chemistry. 52 water samples were collected for the determination of major ions and environmental isotopes of δ¹⁸O and δ²H. Stoichiometry of geochemical data with mixing end members and multivariate statistical analysis were employed with integrated GIS approach for data interpretations. The δ¹⁸O and δ²H of the Jialing River Basin (JRB) were used to define the origin of river water from meteoric water and water in the spring season is affected by high evaporation and evaporates dissolution. The average TDS 301 mg/L that is higher than the Yangtze River. In the JRB, 80% of the anion in water samples represented HCO₃⁻ (207 mg/L) and SO₄²⁻ (80 mg/L) while 80% of the cations were accounted by Ca²⁺ (59.8 mg/L) and Mg²⁺ (17.9 mg/L). The water chemistry mainly derived from the water rock interaction. Piper plot indicated that Ca-Mg-HCO₃⁻ was the most dominant water type and most ions derived from carbonate weathering by H₂SO₄ and H₂CO₃. The stoichiometry results further confirmed carbonate weathering is dominant than silicate weathering. Evaporate ions were modified by anthropogenic sources. Agricultural inputs are higher than the industry and atmospheric inputs. Redundancy analysis showed that most contributive land-use type in explaining riverine chemistry was the cultivate land (62.6, 66.4, and 67.9%) at all buffer scales of 30, 20, and 10 km, respectively. Forest and grasslands mostly correlate with Ca²⁺, Mg²⁺, Cl⁻, SO₄²⁻, EC, pH, and HCO₃⁻ while anthropogenic land-use types such as cultivated and construction lands correlate with Na⁺, K⁺, Cl⁻, and NO₃⁻. These results revealed that the lithology of the basin mainly controlled the upstream water chemistry while downstream riverine chemistry was controlled by both lithology and anthropogenic inputs. Nevertheless, this study suggested that explicitly determining the controlling factors of riverine chemistry involves a complex process and combination of different chemical constituents and factors on river water. However, this study managed to provide useful information to further understanding of the geochemical process in JRB.
Mostrar más [+] Menos [-]Convergence analysis of China’s energy intensity at the industrial sector level Texto completo
2019
Huang, Junbing | Zheng, Xuemei | Wang, Ailun | Cai, Xiaochen
China’s industrial energy consumption accounted for approximately 70% of national energy demand in the past four decades. Regarding energy demand and environmental pollution, success in controlling energy demand and reducing energy intensity for industrial sectors in China would play a crucial role for the country’s sustainable growth problems. To formulate targeted energy plans, the features and characters of China’s industrial energy intensity should be carefully evaluated. In this study, a carefully designed econometric model that considers different technological factors including indigenous R&D and technology spillovers from foreign direct investment and trade under a united framework is applied to investigate the β-convergence characteristics for China’s industrial energy intensity by employing a panel dataset covering China’s 34 industrial sectors over 2000–2010. The results verify the existence of β-convergence in industrial energy intensity during the sample period. For the industrial sectors overall and the light industrial sectors, the empirical results indicate that indigenous R&D and technology spillovers from FDI and imports are beneficial in curbing energy intensity. However, technology spillover through exports makes it harder to reduce energy intensity. In addition, not all technological factors have played a significant role in reducing energy intensity for the heavy industrial sectors.
Mostrar más [+] Menos [-]Field experiment on the effects of sepiolite and biochar on the remediation of Cd- and Pb-polluted farmlands around a Pb–Zn mine in Yunnan Province, China Texto completo
2019
Zhan, Fangdong | Zeng, Wenzeng | Yuan, Xingchao | Li, Bo | Li, Tianguo | Zu, Yanqun | Jiang, Ming | Li, Yuan
The effects of sepiolite and biochar on the contents of available nutrients (N, P, and K); the chemical forms and available contents of Cd and Pb in soils; the biomass and growth of maize; and the contents of nutrients, Cd, and Pb in maize were studied in situ in Cd- and Pb-polluted farmlands around the Lanping Pb–Zn mine in Yunnan Province, China. Results demonstrated that sepiolite did not influence the contents of available nutrients in soils, although it significantly increased the pH value and decreased available Cd (CaCl₂-extractable and exchangeable) contents and exchangeable and reducible Pb. Moreover, sepiolite increased the biomass in the aboveground part of maize, resulting in the reduction of Cd contents in maize plants and grains by 25.6–47.5%. Meanwhile, the biochar increased the contents of available nutrients in soils and decreased the contents of exchangeable Pb in soils and biomass in the aboveground part of maize plants and grains; decreased the Cd contents in maize stems and grains by 26.7% and 24.6%, respectively; and decreased the Pb content in roots by 16.2%. However, neither sepiolite nor biochar had considerable influence on the Pb content in maize grains. According to a correlation analysis, soil pH has extremely significant negative correlations with available Cd content in soils, which in turn have extremely significant positive correlation with the Cd content in maize plants and grains. These results revealed that sepiolite increases soil pH and decreases Cd bioavailability in farmland soils around the Pb–Zn mine. Furthermore, biochar increases the contents of available nutrients in farmland soils and the maize yield. Sepiolite and biochar both decrease the contents and transfer coefficients of Cd in maize plants and grains and are, thus, applicable to the immobilization remediation of Cd-polluted farmlands.
Mostrar más [+] Menos [-]Composting of municipal solid waste by different methods improved the growth of vegetables and reduced the health risks of cadmium and lead Texto completo
2019
Shah, Ghulam Mustafa | Tufail, Nadia | Bakhat, Hafiz Faiq | Ahmad, Iftikhar | Shāhid, Muḥammad | Hammad, Hafiz Mohkum | Nasim, Wajid | Waqar, Atika | Rizwan, Muhammad | Dong, Renjie
Reutilization of putrescible municipal solid wastes (MSW) in agriculture can provide valuable plant nutrients. However, it may pose serious noncarcinogenic health risks for a human when contaminants, especially the heavy metals in MSW, end up in plants through the waste-soil-plant continuum. This study examined the effects of composting methods viz. aerobically (AC), anaerobically (ANC), and aerobic-anaerobically (AANC) composted MSW material on (i) fertilizer value: vegetable yield, nitrogen (N) mineralization, and apparent N recovery (ANR); and (ii) associated health risks: selected heavy metal concentration, daily intake of metals (DIM), health risk index (HRI), hazard index (HI), and target hazard quotient (THQ) when applied to a loamy soil. All the aforementioned compost materials were incorporated into the sandy loam soil filled in pots and carrot and spinach were cultivated for 85 and 90 days, respectively. After soil application, between 51 and 56% of the applied organic N was mineralized from ANC material, while the values in case of AC and AANC were 26–31% and 34–40%, respectively. Consequently, dry matter yield and vegetable N uptake from composts were in the order ANC > AANC > AC (P < 0.05). Further, vegetable ANR was the highest from ANC (56 and 56%) than AANC (42 and 45%), and AC (30 and 33%) for spinach and carrot, respectively (P < 0.05). Interestingly, plant uptake of lead and cadmium was lowest from ANC as compared to AC or AANC (P < 0.05), irrespective of the vegetable type. Consequently, DIM, HRI, and THQ for these metals were substantially lower in the former as compared to the latter compost materials. Further, HI from ANC material was 50% lower over the unfertilized control indicating the absence of noncarcinogenic human health risks via vegetable intake. This all indicates that from viewpoint of sustainable waste recycling in agriculture, anaerobic composting is superior to the other composting methods.
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