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Karachi, Pakistan

Khan M.N.,University of Karachi | Sarwar A.,Fuel Research Center
Atmosfera | Year: 2014

Air pollution has been considered one of the most important environmental challenges because of its direct effect on ecosystems and human health. Temporal changes in the composition of 20 samples of rainwater in the arid region of Karachi, Pakistan during the southwest monsoon of 2009 have been monitored to carry out the indirect assessment of air quality. The study has been fulfilled with the aim of identifying the level of air pollution, and the relative contribution of possible anthropogenic activities. Metal ions were analyzed to predict health risks. Rain samples were found to be alkaline (pH 5.55-7.55) due to the influence of calcium and magnesium rich particles. Continuous rains in consecutive days showed a remarkable decline in air pollution while the dry season boosted up the level of pollution. Strong correlations of total dissolved solids with K+, Na+, Ca2+, Mg2+, and Cl- were observed. A relatively weak correlation of total suspended particles with metals showed the possibility of some other particulate matters being suspended in the air. Principal component analysis and analysis of means were used to predict the anthropogenic source of pollution. This study will be helpful to formulate strategic planning and policies for controlling the level of air pollution in the city. Source


Khan M.N.,University of Karachi | Wasim A.A.,University of Karachi | Sarwar A.,Fuel Research Center | Rasheed M.F.,University of Karachi
Environmental Monitoring and Assessment | Year: 2011

The assessment of the toxicants in roadside soil on regular basis has become extremely essential with the increase in awareness for the metal toxicity in the environment. The present study investigates the presence of toxic metals along National Highway (N-5), Pakistan. Averages of about 1.3 million per month of automobile vehicles ply on this route. Lead (Pb), zinc (Zn), copper (Cu), nickel (Ni), cadmium (Cd), cobalt (Co), manganese (Mn), mercury (Hg), and iron (Fe) were analyzed by atomic absorption spectrophotometry in roadside soil at the nine selected locations along the highway. Strong Pearson correlations (α = 0.05) were found between Pb and Zn (r 2 = 0.887), Fe and Mn (r 2 = 0.880), Hg and Cd (0.864), Cu and Zn (0.838), and Cu and Pb (0.814). The correlation between the elemental compositions of the main automobile components revealed vehicular traffic as the main non-point source of roadside soil pollution. Extremely high level of mercury, 144.05 mg kg -1, was found at S5. It was revealed that the unregulated incineration and dumping sites of hazardous waste material along N-5 were also responsible for these contaminations. Multivariate analysis on the obtained data also disclosed the same interpretation. Cluster analysis of the data grouped Pb, Zn, and Cu at 85.23% similarity, whereas, Cd, Hg, and Ni were grouped at 78.75% similarity basis. The findings need swift action against the root cause of soil pollution. © 2011 Springer Science+Business Media B.V. Source


Sarwar A.,Fuel Research Center | Khan M.N.,University of Karachi | Azhar K.F.,Scientific Information Center
Energy Sources, Part A: Recovery, Utilization and Environmental Effects | Year: 2014

The samples of Thar coalfield were characterized using a thermogravimetric analyzer, atomic absorption spectrophotometer, X-ray diffractometer, Fourier transform infrared spectra, and scanning electron microscopy-energy dispersive x-ray spectroscopy analysis. The samples were ranked as lignite and subbituminous according to American Society for Testing and Materials standard classification. Differential thermogravimetric analysis results specified chemical reactivity of coal at the primary devolatilization region (257-412°C) and secondary devolatilization region (741-900°C). The minerals identified were quartz, kaolinite, dikite, halloysite, gold copper indium, graphite hydrogen nitrate, and magnesium vanadium molybdenum oxide. X-ray diffraction study confirmed the presence of mineral constituents as indicated by microscopic investigation. Fourier transform infrared spectra identified C=C aromatic groups at 1,500-1,700 cm-1 as maturity indicator and 2,800-3,000 cm-1 and 2,300 cm-1 as aliphatic stretching regions. The peaks of quartz and kaolinite were observed at 900-1,100 cm-1. Strong correlations between mineral matter-SiO 2 (r 2 = 0.808) and Al2O3-SiO2 (r 2 = 0.957) indicates Al and Si as the dominant inorganic components. Cluster analysis appeared as an additional tool for coal ranking based on their physicochemical properties. © 2014 Copyright Taylor and Francis Group, LLC. Source


Khan M.N.,University of Karachi | Soherwardy R.,University of Karachi | Sarwar A.,Fuel Research Center
International Food Research Journal | Year: 2015

Since last few years, olive fruits consumption has been increased to many folds in the country. Shelves of superstores have been occupied by olive fruit products from different commercial presentations. Eight olive fruit samples of different cultivars were analyzed for physicochemical characterizations to assess their nutritional values. Water content was found higher in Jordanian Cipressino, French Atton Manzanilla, and Spanish Reding samples and lower in Egyptian sample. Several factors such as variety, maturation level, growing environment, mode of irrigation, and processing method may be responsible for this variation. Calorific values ranged from 3.87-7.32 Cal/g contributing significantly in daily energy intake. Olives were found to be a good source of K, Na, Ca, Mg, and Fe. Traces of Mn, Co, Ni, Cu, Zn, Pb and Cd were also found. Significant differences were observed for K (p=0.016), Na (p=0.032) Cu (p=0.049), and Mn (p=0.047) in green, ripe and brine olives. French Atton Manzanilla and Labanon Nevadillo were identified as good varieties in terms of Na/K, and Ca/Mg ratios. Chemometric technique was used to discriminate the samples between green, ripe, and brine on the basis of K, Na, Ca, and Mn. © All Rights Reserved. Source


Khan M.N.,University of Karachi | Sarwar A.,Fuel Research Center | Bhutto S.,Government of Pakistan | Wahab M.F.,NED University of Engineering and Technology
International Journal of Food Properties | Year: 2010

Six strawberry samples, commercially grown in Pakistan, were studied for physicochemical properties. All samples have high level of water and low contents of ash and volatile compounds. The berry was found to be a good source of potassium (1.14-1.93 g/kg), magnesium (0.12-0.15 g/kg), calcium (79.59-124.11 mg/kg) and sodium (23.51-36.03 mg/kg). The lead and cadmium contents were below the detection limits (1.0 ± 0.1 μg/l for lead and 0.1 ± 0.01 μg/l for cadmium). Principal component analysis and cluster analysis were found to be good statistical tools for the evaluation of the compositional variations with respect to geographical origin. Copyright © 2010 Taylor & Francis Group, LLC. Source

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