Уточнить поиск
Результаты 2501-2510 из 4,896
Biomonitoring of Water Bodies in Metro Manila, Philippines Using Heavy Metal Analysis and Erythrocyte Micronucleus Assay in Nile Tilapia (Oreochromis niloticus)
2019
Zeba F. Alam, Charilen Kei V. Concepcion, Johnray D. Abdulrahman and Miguel Alvaro S. Sanchez
Environmental biomonitoring of water bodies is routinely done to assess the ecological state of aquatic systems by detecting the hazardous and genotoxic pollutants. In this study, a combination of atomic absorption spectroscopy and the fish micronucleus assay was used to determine and compare the genotoxic potential of water bodies specifically the two Esteros namely, Estero de Vitas and Estero de Paco, which are part of the Pasig River System, Philippines. As part of the strategy, the Esteros are being rehabilitated to control pollution in the river systems whereby Estero de Paco was recently rehabilitated, whereas, Estero de Vitas is still largely neglected. The elevated levels of micronuclei and nuclear abnormalities were observed in the erythrocytes of the genetic model, the Nile tilapia (Oreochromis niloticus) exposed to water samples from the two sources tested when compared to a control group indicating the presence of genotoxic and hazardous pollutants in the water bodies of Estero de Paco and Estero de Vitas. Further, the water samples from Estero de Vitas were found to be far more genotoxic as compared to the water samples from Estero de Paco (p<0.05). The observed genotoxic effects of the water samples appeared to be related to the physico-chemical characteristics studied using atomic absorption spectroscopy, which showed the presence of heavy metals in the water samples from both the sources. The AAS results also confirm the presence of heavy metals in the fish tissue exposed to the water samples from the two locations. Hence, the tilapia fish (a component of Filipino diet) should be consumed with precautions as it can absorb the heavy metals present in ecosystems. The results establish that the fish micronucleus test is an effective assay for environmental biomonitoring. The lower genotoxicity potential of Estero de Paco clearly demonstrates that the restoration of the Esteros can be an effective approach to control pollution of the water bodies, especially the Pasig river system.
Показать больше [+] Меньше [-]Forecasting of Heavy Metal Contamination in Coastal Sea Surface Waters of the Karachi Harbour Area by Neural Network Approach
2019
Muhammad Ayaz and Nasir-Uddin Khan
The major and overriding factors affecting water quality and the aquatic ecosystems in the coastal areas are sewage and nutrient inputs from municipal and industrial wastewater, depletion of seaside contrivances, risks of public health as well as loss of biodiversity. The coastal area of the Karachi harbour is most heavily polluted due to these reasons. In this study, we proposed the artificial neural network (ANN) models to monitor and control the sea surface water quality of the Karachi coastal area along the harbour. Recently, various types of ANN have been successfully applied in hydrological fields. In this study, Nonlinear Auto Regressive eXogenous Neural Network (NARX-NN) shall be applied to predict the concentration of heavy metals in coastal sea surface water of the Karachi harbour area. This method provides significant insight into the comparative study of two different training functions of NARX-NN, namely, Levenberg-Marquardt (LM) and Scale Conjugate Gradient (SCG). The physical parameters like sea surface temperature (SST), salinity, tides and pH are taken as an input and the chemical parameters chromium, copper, lead, nickel and zinc are taken as output individually for all six locations. The performance of the model was evaluated by statistical criteria that include a correlation coefficient (r) and mean square error (MSE). The prediction results indicated that the LM training function is superior to SCG training function. Hope this study is helpful for local authorities and policy makers to develop a new infrastructure and install a water treatment plant to reduce the water pollution of the harbour area.
Показать больше [+] Меньше [-]Land Evaluation by Integrating Remote Sensing and GIS for Rainfed Agriculture in Koranahalli Subwatershed
2019
D. Ravikumar and Govindaraju
In the present study, an assessment of land suitability potential for agriculture in the Koranahalli subwatershed area has been conducted through a close examination of the different indicators of land characteristics and qualities. The objective of this study is to assess the land resource and generate a potential map of the study area. The database on soil resources and land use/land cover data was generated by using remote sensing satellite data and soil survey to perform an integrated analysis in the GIS environment. Fourteen series were identified after detailed soil survey based on the soil characteristics. About 150 soil mapping units were grouped into good and moderate and fairly good cultivable land. Soil site suitability evaluation for different crops revealed that, about 4.36 percent of area is highly suitable for sorghum, followed by 36.92, 35.20, 34.89, 33.60, 31.75 percent and 31.11 percent of area is moderately suitable for chilli, chickpea, ragi, pomegranate, sorghum and sunflower respectively. About 37.44, 31.33, 30.07, 29.81 and 29.76 percent of area is marginally suitable for cultivating tomato, redgram, ragi, sunflower and sorghum or chickpea. However, 30.94, 25.39, 5.89 and 4.95 percent of the area is not suitable for cultivating castor, sapota, pomegranate and redgram or sunflower due to the limitation of soil depth and gravelliness or stoniness.
Показать больше [+] Меньше [-]Influence of Tourism Industry Development on Environmental Pollution and EcoCompensation Measures in Chongqing City, China
2019
Jixia Zhou
Ecological environment is not only the basis for human survival and development but also the carrier of tourism industry development. However, such a basis for survival and development of the tourism industry is damaged given the excessive pursuit of economic benefits and neglect of ecological environmental protection in tourist attractions. Eco-compensation measures protect the tourism ecosystem and coordinate the contradiction between tourism industry development and ecological protection. Thus, the sustainable development of the tourism industry can be facilitated. In this study, research on environmental pollution caused by the tourism industry in Chongqing City, China, and relevant eco-compensation measures were first reviewed. Second, an empirical study on the relations of total tourism revenues with waste gas emission, wastewater discharge, and industrial solid waste emission in Chongqing City was conducted using a vector autoregression model. The study findings show that tourism industry development can influence environmental pollution slightly and that an eco-compensation mechanism coordinates the relationship between tourism and ecological environment. Tourism economic growth has long-term equilibrium relations and mutual Granger causality with waste gas emission, wastewater discharge, and industrial solid waste emissions. The conclusions provide a reference to understand the dynamic relations between tourism industry development and environmental pollution, construct a guarantee system for tourism eco-compensation mechanism, and achieve sustainable development of tourism industry and environmental protection.
Показать больше [+] Меньше [-]Simultaneous Removal of Cu(II) and 1-Naphthol in Wastewater by Magnetic Nanoparticle-Graphene Oxide Composites
2019
Jie Luo, Donglin Zhao, Linxia Wang, Abdullah M. Asiri and Khalid A. Alamry
A graphene-based magnetic composite (Fe3O4/GO) was prepared and used for simultaneous removal of Cu(II) and 1-naphthol. The composite was characterized by SEM, TEM, XRD, FT-IR and Raman. Electron microscopy reflected that Fe3O4 spheres were dispersed on graphene layers. The pseudo-second-order kinetic and Langmuir isotherm models could best describe the sorption kinetics and isotherms. The sorption of Cu(II) and 1-naphthol increased with increasing temperature, and thermodynamic parameters calculated from temperature dependent sorption revealed that sorption of Cu(II) and 1-naphthol on Fe3O4/GO was spontaneous and endothermic. The results indicated that Fe3O4/GO can be utilized as potential adsorbents for purification of co-contaminated water systems.
Показать больше [+] Меньше [-]Microbial Fuel Cells as Source of Clean Energy - Potential and Pitfalls
2019
Tabassum-Abbasi, Tasneem Abbasi and S. A. Abbasi
Microbial fuel cell (MFC) is one among several other technologies which are being vigorously explored on the assumption that they can achieve pollution control with concomitant generation of ‘clean’ energy. In this study, the techno-economical problems associated with MFCs have been identified and catalogued in the context of the fuel cell technology in general and MFCs in particular. It is shown that even as the attention of the supporters of MFCs is riveted on the ability of MFCs to generate electricity directly from organic waste, the high costs and the pollution that the making, operation, decommissioning, and disposal of MFCs entails, is not taken into account. Once this is done, MFCs prove not only prohibitively costly but environmentally incompatible as well. In this respect MFCs are one among numerous other waste-to-wealth technologies whose promise was never fulfilled because the energy they generated might have been clean but the process of that generation was very unclean as well as expensive. The study underscores the harm caused by the expectations associated with MFCs and other similar, perpetually ‘likely to succeed’, technologies because in the vain hope that such options will one day enable ‘clean’ treatment of waste we keep generating ever larger quantities of waste instead of focusing on what is viable: waste reduction and conservation of resources.
Показать больше [+] Меньше [-]Effects of a Novel Soil Remediation Agent on Cadmium Contaminated Soil
2019
Chuang Ma, Bin Hu, Fu-Yong Liu, Chang-Chang Jia, Ming-Bao Wei and Hong-Zhong Zhang
A novel type of NH2-functionalized carbon-coated Fe3O4 core-shell nanoparticles (Fe3O4@C-NH2) soil remediation agent was prepared. The effects of the Fe3O4@C-NH2 application rate, pH, water content, soil conductivity, soil organic matter (SOM) and solidification time on the solidification efficiency of cadmium (Cd) in Cd-contaminated soils were investigated. The results showed that the structure of Fe3O4@C-NH2 had a hollow core-shell, the carbon shell was well dispersed, the -NH2 bonding was obvious and the adsorption of Fe3O4@C-NH2 to Cd2+ in water quickly reached equilibrium within 20 min, with a saturated adsorption capacity of 78.83 mg.g-1. The Fe3O4@C-NH2 application rate and soil organic matter (SOM) had a great influence on solidification efficiency. SOM mainly affected the transition from weak acidity to reducible and oxidizable state, while solidification time affected the transition from oxidizable state to residual state. The optimal conditions for Fe3O4@C-NH2 solidification of Cd are: application rate of 3%-4% (3.3%), pH of 6-10 (7.33), moisture content of 40%-60% (50%), conductivity of 90-400 µS.cm-1 (142.6 µS.cm-1), SOM of 45.00-65.00 g.kg-1 (63.04 g.kg-1) and solidification time of no less than 10 days. Under the optimal conditions, the solidification efficiency of Fe3O4@C-NH2 for Cd was 42.95±1.89%, which significantly reduced the leaching and migration of Cd and achieved the goal of remediation.
Показать больше [+] Меньше [-]Comparative Study on the Treatment of Landfill Leachate by Coagulation and Electrocoagulation Processes
2019
C. Ramprasad, Karthik Sona, Mohammed Afridhi, Ram Kumar and Naveenatha Gopalakrishnan
Landfill leachate is a complex mixture of organic and inorganic compounds and their concentration level highly depends on the type of waste dumped, age of the landfill, etc. Last few decades, the researchers are exploring the feasibility of treating landfill leachate using physicochemical, biological, advanced processes and combination of these methods. The current study focused on the comparison of two commonly adopted technologies for landfill leachate treatment, chemical coagulation/flocculation and electrocoagulation process. The leachate samples were collected from two different places and examined for the following parameters: pH, turbidity, chemical oxygen demand, chlorides, alkalinity, hardness, solids and nutrients. The current study focused on studying the effect of different inorganic coagulants (alum and ferric chloride), coagulant dosages, different electrode material (titanium coated with platinum/stainless steel and aluminium/stainless steel), electrolysis time and current intensity on the removal of pollutants from leachate and reuse for non-potable applications. The raw leachates collected from the two sites were found to be significantly different in their characteristics due to the age of landfill and physiognomies of wastes dumped. The batch treatment studies showed that both the treatment systems are nearly displaying a similar kind of removal efficiency (more than 74%). Amongst that, the coagulation/flocculation process showed a better removal efficiency and cost effectiveness compared to electrocoagulation process. Additionally, the treated water was found to be not meeting the Indian Standard for inland disposal. Therefore, an additional post treatment like reed bed process or sand filtration will be a viable option for non-potable applications.
Показать больше [+] Меньше [-]Development Performance and Influencing Factors of Environmental Protection Industry in China
2019
Ming Wei
As a strategic emerging industry, environmental protection industry is important in the development of national economy. However, few empirical studies on the performance of environmental protection industry are carried out. In order to explore development performance and influencing factors of environmental protection industry in China, the selection of development data of China’s 31 provincial regions under the environmental protection industry was conducted based on industrial efficiency, economic contribution, industrial scale, and development speed. Development performance of environmental protection industry was qualitatively analysed and influencing factors were explored by using the method of factor analysis. Results show that the factor score of the eastern region is positive in both industry scale and pollution treatment. Factor score of industry scale, industry contribution and pollution treatment in the central region is positive. Development of environmental protection industry in the western region lags far behind other areas, and only factor score of industry contribution are positive and significantly higher than other areas. Factor score of industrial scale, industrial contribution, and pollution treatment in the northeast region is lower than that in the eastern and central region. Suggestions and countermeasures are proposed to promote the development of the environmental protection industry.
Показать больше [+] Меньше [-]Biofuel from Bryophyta as an Alternative Fuel for Future
2019
Sandeep Sirohi, Chitra Yadav and Debjyoti Banerjee
Today’s growing demand for energy has emphasized the need for the search for renewable resources. This demand can be met with by using alternative resources such as biofuel, rather than just depending on non-renewable resources. Therefore, the present study has been undertaken to extract lipid from a species of Bryophyta, i.e. Marchantia polymorpha. 0.044 g of lipid was extracted from 8 g of the bryophyte. Bligh and Dyer method was used for the extraction of lipid. It is a multi-step process in which methanol, chloroform, and NaCl play an important role in the extraction of bioproduct in the form of oily bodies. This small step taken towards energy utilization and conservation will open the new vista to mitigate the problem of energy crisis.
Показать больше [+] Меньше [-]