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CONTENTS
Volume 6, Number 4, December 2017
 

Abstract
This study was conducted to investigate the levels of heavy metals in twelve species of vegetables and assessment of health risk. Samples were analyzed using inductively coupled plasma mass spectrometer (ICP-MS). The ranges of Cr, Ni, Cu, As, Cd and Pb in vegetables species were 0.37-5.4, 0.03-17, 0.35-45, 0.01-2.6, 0.001-2.2, and 0.04-8.8 [mg/kg, fresh weight (fw)], respectively. The concentrations of As, Cd and Pb in most vegetable species exceeded the maximum permissible levels, indicating unsafe for human consumption. Health risks associated with the intake of these metals were evaluated in terms of estimated daily intake (EDI), and carcinogenic and non-carcinogenic risks by target hazard quotient (THQ). Total THQ of the studied metals from most of the vegetables species were higher than 1, indicated that these types of vegetables might pose health risk due to metal exposure. The target carcinogenic risk (TR) for As ranged from 0.03 to 0.48 and 0.0004 to 0.025 for Pb which were higher than the USEPA acceptable risk limit (0.000001) indicating that the inhabitants consuming these vegetables are exposed to As and Pb with a lifetime cancer risk. The findings of this study reveal the health risks associated with the consumption of heavy metals through the intake of selected vegetables in adult population of Bangladesh.

Key Words
toxic metals; vegetables species; health risk; Bangladesh

Address
Md. S. Islam: 1.) Department of Soil Science, Patuakhali Science and Technology University, Dumki, Patuakhali-8602, Bangladesh

2.) Graduate School of Environment and Information Sciences, Yokohama National University, Japan

Md. K. Ahmed: Department of Oceanography, Dhaka University, Dhaka-1000, Bangladesh

Ram Proshad: Department of Soil Science, Patuakhali Science and Technology University, Dumki, Patuakhali-8602, Bangladesh

Saad Ahmed: Department of Soil Science, Patuakhali Science and Technology University, Dumki, Patuakhali-8602, Bangladesh

Abstract
This work investigated the use of sugarcane bagasse ash (SCBA) generated by an energy co-generation process in sugarcane mill as an alternative raw material in soil-cement brick. The SCBA obtained from a sugarcane mill located in southeastern Brazil was characterized with respect to its chemical composition, organic matter content, X-ray diffraction, plasticity, and pozzolonic activity. Soil-cement bricks were prepared by pressing and curing. Later, they were tested to determine technical properties (e.g., volumetric shrinkage, apparent density, water absorption, and compressive strength), present crystalline phases, and microstructural evolution. It was found that the SCBA contains appreciable amounts of silica (SiO2) and organic matter. The results showed that the SCBA could be used in soil-cement bricks, in the range up to 30 wt. %, as a partial replacement for Portland cement. These results suggest that the SCBA could be valorized for manufacturing low-cost soil-cement bricks.

Key Words
sugarcane bagasse ash; soil-cement brick; building material; recycling

Address
Mateus C. Amaral: Department of Engineering, Fluminense Federal University, Rua Recife, s/n,
Rio das Ostras-RJ 28895-532, Brazil

José N. F. Holanda: Laboratory of Advanced Materials, State University of Northern Fluminense, Av. Alberto Lamego 2000, Campos dos Goytacazes-RJ 28013-602, Brazil

Abstract
The climate change has made adverse effects on land surface temperature for many regions of the world. Several climatic studies focused on different downscaling techniques for climatological parameters of different regions. For statistical downscaling of any hydrological parameters, conventional Neural Network Models were used in common. However, it seems that in any modeling study, uncertainty is a vital aspect when making any predictions about the performance. In this paper, Gamma Test is performed to determine the data length selection for training to minimize the uncertainty in model development. Another measure to improve the data quality and model development are wavelet transforms. Hence, Gamma Test with Wavelet decomposed Feedforward Neural Network (GT-WNN) model is developed and tested for downscaled land surface temperature of Patna Urban, Bihar. The results of GT-WNN model are compared with GT-FFNN and conventional Feedforward Neural Network (FFNN) model. The effectiveness of the developed models is illustrated by Root Mean Square Error and Coefficient of Correlation. Results showed that GT-WNN outperformed the GT-FFNN and conventional FFNN in downscaling the land surface temperature. The land surface temperature is forecasted for a period of 2015-2044 with GT-WNN model for Patna Urban in Bihar. In addition, the significance of the probable changes in the land surface temperature is also found through Mann-Kendall (M-K) Test for Summer, Winter, Monsoon and Post Monsoon seasons. Results showed an increasing surface temperature trend for summer and winter seasons and no significant trend for monsoon and post monsoon season over the study area for the period between 2015 and 2044. Overall, the M-K test analysis for the annual data shows an increasing trend in the land surface temperature of Patna Urban.

Key Words
gamma test; downscaling; wavelet decomposition; neural network; temperature

Address
Thendiyath Roshni and Nandini Kumari: Department of Civil Engineering, National Institute of Technology Patna, Patna, India

Remesan Renji: School of Water Resources,Indian Institute of Technology Kharagpur, Kharagpur, India

Jayakumar Drisya: Department of Civil Engineering, National Institute of Technology Calicut, Calicut, India

Abstract
Single (0.005 M DTPA), sequential (six-step) and kinetic (0.05 M EDTA) extractions were performed to assess Cd, Cr, Cu, Ni, Pb, and Zn mobilization and their potential ecological risks in Abuja (Nigeria) water (WTS) and wastewater (WWTS) treatment sludges. Total metal levels (mg/kg) in WTS and WWTS, respectively were: Cd(3.67 and 5.03), Cr(5.70 and 9.03), Cu(183.59 and 231.53), Ni(1.33 and 3.23), Pb(13.43 and 17.87), Zn(243.45 and 421.29). DTPA furnished metal extraction yields (%) in WTS and WWTS, respectively as: Cd(11 and 6), Cr (15 and 7), Cu(17 and 13), Ni(23 and 3), Pb(11 and 12), and Zn(37 and 33). The metals were associated with the soluble/exchangeable, carbonate, Mn/Fe-oxide, organic matter and residual forms to varying degrees. Kinetic extractions cumulatively leached metal concentrations akin to the mobilizable fractions extracted sequentially and the leaching data fitted well into the Elovich model. Metal mobilities were concordant for the three leaching procedures and varied in the order:WTS>WWTS. Calculated ecological risk indices suggested moderate and considerable metal toxicity in WTS and WWTS, respectively with Cd as the worst culprit. The findings may be useful in predicting heavy metals bioavailability and risks in the sludges to guide their disposal and use in land applications.

Key Words
heavy metal; single extraction; sequential extraction; kinetic extraction; ecological risk; industrial sludge

Address
Raymond A. Wuana, Ishaq S. Eneji and Ezekiel C. Ugwu: Department of Chemistry and Centre for Agrochemical Technology, Federal University of Agriculture, Makurdi 970001, Nigeria

Abstract
An Amberlite XAD-4 resin impregnated with di(2-ethylhexyl)phosphoric acid was prepared and its adsorption-desorption behaviors with Sr(II) ions under various conditions was examined. The resin was characterized by fourier transform infrared and thermal analysis techniques. The effects contact time, temperature, pH, interfering ions and eluants were studied. Results showed that adsorption of Sr (II) well fitted with pseudo-second-order kinetic model. The equilibrium adsorption data of Sr (II) on the impregnated resin were analyzed by Jossens, Weber-van Vliet, Redlich-Peterson and Fritz-Schlunder models to find out desirable equilibrium condition. Among them, the Fritz-Schlunder model best fitted to the experimental data. The maximum sorption capacity of impregnated resin amounted to 0.45 mg/ g at pH 8.0 and 20oC.

Key Words
strontium removal; Amberlite XAD-4; di (2-ethylhexyl) phosphoric acid; isotherm study

Address
Hossein Sid Kalal , Ali Reza Khanchi, Mojtaba Nejatlabbaf,
Mohammad Reza Almasian, Kamal Saberyan and Mohammad Taghiof: Materials and Nuclear Fuel Research School, Nuclear Science and Technology Research Institute, AEOI, P.O. Box 11365-3486, Tehran, Iran


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