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Comparative assessment of the effects of meso-2,3-dimercaptosuccinic acid and salinomycin on spleen function of cadmium-exposed mice
2019
Kamenova, Kalina | Gluhcheva, Yordanka | Dorkov, Petar | Ivanova, Juliana
In this study, we present experimental data on the effects of meso-2,3-dimercaptosuccinic acid (DMSA) and tetraethylammonium salt of salinomycinic acid (Sal) on cadmium-induced spleen dysfunction and altered essential metal balance in mice. Sixty-day-old male mice (ICR line) were randomly divided into four groups: untreated control group (Ctrl)—obtained distilled water for 28 days, toxic control group (Cd)—exposed to cadmium acetate dihydrate at average daily dose of 20mg/kg body weight (BW) for 14 days, Cd + DMSA group—obtained cadmium acetate dihydrate as the toxic control group followed by treatment with 20mg/kg BW DMSA for 2 weeks, and Cd + Sal group—mice exposed to cadmium acetate dihydrate at average daily dose of 20mg/kg BW for 2 weeks followed by administration of Sal at an average daily dose of 20mg/kg BW for 2 weeks. The compounds were administered orally via the drinking water of the animals. We found that cadmium exposure caused splenomegaly and reduced the hemoglobin and hematocrit levels and total red blood cell count compared with untreated controls. Cadmium intoxication of mice induced accumulation of the toxic metal ion in the blood and spleen. Alterations in the endogenous levels of calcium (Ca) and iron (Fe) in the spleen of cadmium-exposed mice compared with those in untreated controls were observed. Treatment of cadmium-exposed mice with DMSA or Sal recovered the spleen weight and hematological parameters to normal control values, decreased cadmium concentration in the blood and spleen, and improved splenic architecture. The results prove that Sal is a potential antidote for treatment of Cd-induced spleen dysfunction.
Mostrar más [+] Menos [-]Monitoring metal pollution on coastal lagoons using Cerastoderma edule—a report from a moderately impacted system in Western Portugal (Óbidos Lagoon)
2019
Veiga, Kelly | Pedro, Carmen A. | Ferreira, Susana M. F. | Gonçalves, Sílvia C.
The main goal of this monitoring program was to evaluate the contamination in the intertidal environment of Óbidos Lagoon by the metals Cd, Pb, and Ni on water, sediments, and on biological samples, using the bivalve Cerastoderma edule (common name: cockle) as a biomonitor. Since C. edule is an edible mollusc, the risk of their consumption by humans from this lagoon was also evaluated. The study was performed in a restricted area of the lagoon—the ML station—where human activities, such as shellfish harvesting, intersect with the natural processes occurring in this system. The results obtained revealed that the water samples were polluted with Cd and Pb with concentrations (0.00025 mg l⁻¹ and 0.0072 mg l⁻¹) above the maximum legislated on the Directive 2008/105/EC, while for Ni, this occurred only on one of the seasons sampled (summer 2010: 0.029 mg l⁻¹). The sediments were not contaminated with Cd and Ni, and the contamination detected for the metal Pb, allowed the classification of this station as an unpolluted site ([Pbmin] = 7.477 mg.kg⁻¹ and [Pbmax] = 19.875 mg.kg⁻¹). On biological samples, comparing the results of metal contaminations with the values of the maximum levels fixed by European Commission Regulation (EC) No 1881/2006 and USFDA, all the results were below the legal value. Therefore, during the period of study, the consumption of this bivalve by humans was safe. Also, BAF and CF calculations suggest that C. edule can be used as a biomonitor to determine the source of the contaminations. This study supported the use of C. edule as a biomonitor to assess the contamination by the metals Pb and Ni at the Óbidos Lagoon and allowed to predict the potential transfer of metals to higher trophic levels with potential impacts on the natural and human communities.
Mostrar más [+] Menos [-]Comparison of drought indices in the analysis of spatial and temporal changes of climatic drought events in a basin
2019
Li, Xue | Sha, Jian | Wang, Zhong-Liang
The standardized precipitation index (SPI) and the standardized precipitation evapotranspiration index (SPEI) based on two different methods were calculated using monthly meteorological data from the Yangtze River Basin. According to the completeness and length of dataset, the monthly data of 35 meteorological stations from 1959 to 2017 were applied in this study. The results revealed that the SPEI calculated by the Penman-Monteith (PM) method performed better than the SPI and the SPEI based on the Thornthwaite (TH) method. Since SPEI_PM considered more meteorological factors and detailed physical processes, it obtained the most reasonable and accurate results of drought trends. Using the variations of SPEI_PM to analyze the decadal changes of drought characteristics in the basin, it could be found that 1980–1989 and 1990–1999 were the most humid periods in the basin, while the drought events became more frequent and severe in the recent decade. The spatial distributions of drought trend, duration and frequency indicated that the stations located in the midstream of the river were most prone to drought events, followed by the upper reaches. Our results provided more information for the regions where severe droughts occurred frequently and last longer, and more attention should be paid to these regions in future catchment management.
Mostrar más [+] Menos [-]Experimental investigation of diesel engine performance fuelled with the blends of Jatropha curcas, ethanol, and diesel
2019
Kavitha, Kutuva Rajaraman | Beemkumar, Nagappan | Rajasekar, Rajendiran
Nonrenewable fossil fuels show increased demand and with fossil fuels at a rapid depleting stage, there seems to be an increase in requirement for alternative fuels too. Biofuels and blended fossil fuels are one of a kind. Nonedible jatropha (Jatropha curcas) oil-based methyl ester was produced and mixed with ethanol and blended with conventional diesel in various compositions. Jatropha biodiesel is used because of its great blending capacity with diesel. Sodium hydroxide is used as a catalyst which allows miscibility between ethanol and diesel. In present epoch, the paucity of fossil fuels and its adverse impact have driven researchers to focus on alternative fuels. Biodiesel is one of the most favorable and promising alternatives in the application of automobiles, boilers, gas turbines, etc. This study targets at finding the engine performance and emission characteristics under various load conditions on Kirloskar single-cylinder VCR research engine by blending both jatropha biodiesel and ethanol with base diesel at various compositions. Both jatropha biodiesel and ethanol have high calorific value which is a most important factor for engine power production. The performance analysis showed that the biodiesel blend of 98% diesel with 1.5% jatropha biodiesel and 0.5% (D98J1.5E0.5) of ethanol had a significant improvement in the engine performance than the conventional diesel.
Mostrar más [+] Menos [-]A pro-environmental behavior model for investigating the roles of social norm, risk perception, and place attachment on adaptation strategies of climate change
2019
Yu, Tai-Kuei | Chang, Yu-Jie | Chang, I-Cheng | Yu, Tai-Yi
Today’s climate change is a major problem and challenge for the global environment and human civilization, and it can lead to dramatical floods over specific regions. As climate change intensifies, climate change adaptation strategies, such as flood insurance, energy taxes, and other risky financial strategies, have drawn worldwide attention and discussion. Risk control methods have been widely used to mitigate the impact of climate change on past flood losses, but past risk control strategies on climate change have not focused on the exploration of the relationship between environment, society, and humans. Based on the theoretical model of pro-environmental behavior, this study compares and analyzes four theoretical models and proposes a modified competitiveness model to effectively predict the pro-environmental behavior of college students with partial least squares (PLS) manner. Social norm could play a dominant role of mediator between risk perception, place attachment, and pro-environmental behavior. Although risk perception and local attachment are positively related to risk financial strategy, the promotion of social norms will increase the intention of risk financial strategy. For intention of risk financial strategies within pro-environmental behavior, the efficiency of enhancing local attachment was higher than that of risk perception.
Mostrar más [+] Menos [-]Pilot-scale application of a single-stage hybrid airlift BioCAST bioreactor for treatment of ammonium from nitrite-limited wastewater by a partial nitrification/anammox process
2019
Saborimanesh, Nayereh | Walsh, David | Yerushalmi, Laleh | Arriagada, Esteban Castillo | Mulligan, Catherine N.
This paper presents the treatment of a nitrite-limited wastewater by partial nitrification/anammox process under different dissolved oxygen (DO) concentrations of < 1.2 mg/L, < 0.5 mg/L, and 0 mg/L, and at temperatures of 35 to 27 °C in a pilot-scale single-stage hybrid bioreactor (BioCAST). The effect of operational parameters on microbial community structure and composition has also been investigated during the 1-year experimental period. Ammonium removal efficiencies of 73 ± 19% at 35–32 °C and 87 ± 9% at 29–27 °C were obtained from a synthetic nitrite-limited wastewater with ammonium concentration of 350–500 mg/L (175–250 g m⁻³ d⁻¹). The adaptation of bacteria to a lower temperature (27 °C) and lower free ammonia concentrations at 27 °C was showed to be key factors leading to the optimal nitrite production by aerobic ammonium-oxidizing bacteria (AOB). No nitrite accumulation was observed due to the effective distribution and transfer of nitrite produced by the AOB in the aerobic zone to the microaerophilic/anoxic zones. The fast enrichment of Candidatus species in the suspended biomass in the anoxic zone at temperatures of 35–30 °C and in the attached biofilm in the microaerophilic zone (DO < 0.5 mg/L) at 29–27 °C suggests that the growth media (e.g., suspended biomass vs attached biofilm) had a minor effect on the diversity of microbial community in this bioreactor. This study supports the effective treatment of nitrite-limited wastewater with ammonium concentrations of < 500 mg/L by partial nitrification/anammox process at 35–27 °C in a single-stage hybrid bioreactor by adjusting the DO concentration to < 0.5 mg/L and by providing longer retention times for aerobic (AOB) and anammox bacteria in the biofilm, which resulted in the long-term suppression of nitrite-oxidizing bacteria (NOB).
Mostrar más [+] Menos [-]The applicability of compost, zeolite and calcium oxide in assisted remediation of acidic soil contaminated with Cr(III) and Cr(VI)
2019
Radziemska, Maja | Wyszkowski, Mirosław | Bęś, Agnieszka | Mazur, Zbigniew | Jeznach, Jerzy | Brtnický, Martin
The effect of soil amendments, i.e., compost, zeolite, and calcium oxide, on the chemical properties of soil contaminated with Cr(III) and Cr(VI) and the uptake of selected heavy metals by spring barley (Hordeum vulgare L.) and maize (Zea mays L.) was determined in a pot experiment. The content of all investigated heavy metals in the tested plants varied significantly in response to the tested soil amendments and increasing concentrations of Cr(III) and Cr(VI). Compost, zeolite, and calcium oxide contributed to an increase in the average yield of the aerial parts of maize plants only in treatments contaminated with Cr(III). The concentrations of Cr, Zn, and Ni in the aerial parts of spring barley and maize were higher in treatments contaminated with Cr(III) than in treatments contaminated with Cr(VI). Calcium oxide induced a significant increase in soil pH relative to the control treatment. In treatments without soil amendments, the average Cr content of soil was higher in pots contaminated with Cr(VI). The concentrations of Zn and Cu in non-amended treatments were negatively correlated with increasing doses of Cr(III) and Cr(VI). Calcium oxide decreased the average content of Cr, Cu, and Ni in all experimental variants. Compost increased the average content of Zn in treatments contaminated with Cr(III) and Cr(IV) relative to non-amended soil.
Mostrar más [+] Menos [-]Rural solid waste—characteristics and leachate pollution assessment for different precipitation levels, China
2019
Yang, Huiyuan | Yue, Bo | Liu, Yanjun | Wu, Xiaohui | Gao, Hong | Zhang, Zhibin | Yan, Zhuoyi
Open dumping adversely affects the environment and remains the most widely used method for waste disposal in many developing rural areas in China. Information regarding the impact of rural solid waste (RSW) on the environment remains limited. The objectives of this study are to investigate the characteristics of RSW and the impact of different precipitation rates, and to evaluate the contamination potential of RSW using a leachate pollution index (LPI). The study showed that leachate concentration was significantly influenced by precipitation rates at the initial precipitation stages. Precipitation rates of 42.00 mm/day appeared to have the largest dilution effects. In contrast, the concentrations of leachate at rainfall rates of 24.00 mm/day and soaking were steady, and no similar trends were observed. The highest amounts of pollutants in leachate were the result of soaking. In the first week of our experiment, the LPI value for each rural area waste sample rapidly increased with rising precipitation rates from soaking to 42.00 mm/day. However, no significant change in LPI was observed thereafter (after 5 weeks) even with increasing precipitation rates. The values of chemical oxygen demand, biochemical oxygen demand, total nitrogen, and NH₃-N in the leachate after 10 weeks were 4.00, 7.34, 1.87, and 2.21 times higher, respectively, than those of the prescribed leachate quality standards in China. The results of our study suggest the following course of action for the three dump sites investigated: in Banqiao, given the size of the population and the size of the waste amount, landfill might be a suitable way for disposing of RSW. In Machen, building a standardized waste collection site would be an economical solution for reducing potential pollution risks. In Jiuduhe, increasing the transportation rate of solid waste might be an effective solution. The results of this study can help to improve the understanding of leachate pollution in Chinese rural areas.
Mostrar más [+] Menos [-]Assessing young consumers’ awareness and participation in sustainable e-waste management practices: a survey study in Northwest China
2019
Ramzan, Sidra | Liu, ChenGuang | Munir, Hina | Xu, Yan
The massive generation of electronic waste (e-waste) and the informal recycling of e-waste are serious concerns in China. As a hazardous waste stream, e-waste calls for sustainable management practices to avoid adverse effects on environment and health. However, consumers’ awareness and active participation are needed to make e-waste management successful. Therefore, this study is an exploratory attempt to investigate young consumer awareness, knowledge, and participation in sustainable e-waste management practices. Meanwhile, the study reviews the current situation of e-waste recycling, its related legislative framework, and practices in China. The survey revealed that the respondents have keen environmental consciousness, while they have low awareness about e-waste-related rules and regulations, recycling programs, and the formal and informal recycling sector. The findings provide valuable insights for practitioners in order to promote environmental awareness and sustainable e-waste management practices among young consumers in China.
Mostrar más [+] Menos [-]Climate change in different geographical units and its impact on land production potential: a case study of Shaanxi Province, China
2019
Fei, Li | Meijun, Zhou | Min, Hu
Land production potential (LPP) was the maximum grain yield in one year that can be produced by land under the limitations of climate conditions and in the absence of pests and diseases and other factors. Whether climate change was increasing or reducing the LPP in a given region was uncertain. Therefore, Shaanxi Province was selected to analyze the regional differences in climate change and its effects on LPP change and to identify the main climatic factor restricting LPP in different regions by combining Global Agro-Ecological Zone (GAEZ) model with the Geodetector model. Results showed that the temperature in Shaanxi Province showed an upward trend in 2000–2015; the rise in temperature to the north of Qinling Mountain (QM) was less than that to the south of QM. However, rising temperature had a yield-improving effect to the north of QM and a yield-decreasing effect to the south of QM. There was a precipitation increase in Arid Sandy (AS) area and Loess Plateau (LP), and the precipitation reduced in all other geographical units. The increase in LPP of Shaanxi mostly was caused by increasing precipitation. However, precipitation was declined and reduced LPP to the south of QM; that is, precipitation decline was the dominated climatic factor for LPP decrease in QM, Hanjiang Basin (HB), and Daba Mountain (DM). To the north of QM, LPP in AS, LP, and Guanzhong Plain (GP) both dramatically increased, mainly improved by rising temperature, increasing precipitation, and rising temperature, respectively.
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