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  • Author or Editor: M. Zaidi x
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Abstract  

The determination of Ce, Yb, Se and Cr has been carried out in the atmosphere of Lahore, Faisalabad, Rawalpindi, Islamabad, Wah Cantt and Khanispur (background area) by INAA. Ce and Cr are associated with anthropogenic activities, while Yb is mainly due to soil derived aerosols. Se represents both anthropogenic as well as soil derived aerosols.

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Abstract  

Industrial units play a significant role in atmospheric pollution. Industrial exhausts deteriorate the atmospheric quality causing unhygienic environment for the people working in the vicinity. This work presents a study of the longitudinal distribution of trace elements of the Sheikhupura industrial area. Three kinds of distribution patterns were observed and are discussed in detail. The results are based on the neutron activation analysis of 16 trace elements.

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Abstract  

Four commercial Saudi Arabian crude oils were characterized by thermogravimetry (TG) and differential thermal analysis (DTA). These crude oils, Arab Berri (AB), Arab Light (AL), Arab Medium (AM) and Arab Heavy (AH), were also subjected to the traditionally employed true boiling point (TBP) distillation and simulated distillation (SIMDIST). The TG/DTA data show that the hydrocarbons present in these crude oils fall into four groups: the volatiles, the low molecular weight, the medium molecular weight and the high molecular weight compounds. These four types of hydrocarbons were observed to display certain trends, such that the volatile and low molecular weight hydrocarbons increased, while the medium and high molecular weight hydrocarbons decreased with the lightness of the crude. The volatile contents of AB, AL, AM and AH crude oils up to 280�C were 50.1, 42.2, 42.3 and 38.5 mass percent, respectively. This confirms that AB is the lightest of these crude oils with maximum volatile content. The mass percentage loss from the TG results is in good agreement with the percentage distilled from TBP (ASTM D 2892) and SIMDIST. During evaporation, the TG mass loss follows a similar trend to those of the TBP and SIMDIST results and thus behaves like distillation. During the oxidative degradation, the TG curve shows a higher mass loss as compared to the distillation data. The higher deviation of the TG mass loss and percentage distilled at the higher-temperature end of the curve may be attributed to the higher content of asphaltenes and carbonaceous material present in AH as compared to the AB crude oil. At around 200�C, the TG mass loss curve intersects the TBP and SIMDIST curves and shows a derivation from distillation behaviour. This intersection temperature of the TG and distillation curves is observed to decrease with the heaviness of the crude and can be an indication of the onset of thermal degradation of hydrocarbons present in the crude oil. On the whole, the TG data closely resemble the distillation results.

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Abstract  

Due to the significance of industrial waste water pollution, which creates severe health hazards in humans, this study concentrates over the reduction and determination of the amounts of toxic metals/pollution parameters in the effluents leached from different processes of the textile industry. The concentrations of metal ions were measured by using neutron activation analysis (NAA) technique. The values of toxic metals such as As (49.1 ± 1.8 mg/L), Cu (42.7 ± 1.5 mg/L), Ni (41.1 ± 3.3 mg/L), Mn (51.1 ± 0.7 mg/L), Sb (1.89 ± 0.04 mg/L), Se (0.41 ± 0.01 mg/L), Co (7.5 ± 0.3 mg/L), Cr (8.5 ± 0.5 mg/L) and Cd (1.21 ± 0.08 mg/L) were found very high in crude textile’s effluents as compared to their standard recommended limits. The immense variation observed among the injurious pollutants of the effluents i.e. pH, temperature, electrical conductivity, turbidity, biological oxygen demands, chemical oxygen demands, total suspended solids, total dissolved solids, total solids etc. The toxic metals and injurious pollutants in the unprocessed effluents have been reduced in the post filtration effluents up to 98% and 96% respectively with the help of an ultra-filtration membrane therapy unit.

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Abstract  

The industrial pollution is exponentially growing in the developing countries due to the discharge of untreated effluents from the industries in the open atmosphere. This may cause severe health hazards in the general public. To reduce this effect, it is essential to remove the toxic and heavy metals from the effluents before their disposal into the biosphere. In this context, samples of the effluents were collected from the textile/yarn, ceramics and pulp/paper industries and the concentrations of the toxic metal ions were determined using neutron activation analysis (NAA) technique. The observed concentration values of the As, Cr and Fe ions, in the unprocessed industrial effluents, were 4.91 ± 0.8, 9.67 ± 0.7 and 9.71 ± 0.8 mg/L, respectively which was well above the standard recommended limits (i.e. 1.0, 1.0 and 2.0 mg/L, respectively). In order to remove the toxic metal ions from the effluents, the samples were treated with pea nut husk fence. After this treatment, 91.5% arsenic, 81.9% chromium and 66.5% iron metal ions were successfully removed from the effluents. Then the treated effluents contained concerned toxic metal ions concentrations within the permissible limits as recommended by the national environmental quality standards (NEQS).

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Abstract  

Due to the inadequate water sources, usually sewerage water and industrial effluents are being use for irrigation of the agricultural land around the industrial areas in Pakistan wherein crops and vegetables are cultivated. As untreated effluents contain heavy elements, toxic metals and organic pollutants that may find its way through food chain to general public and may cause health hazards. It is, therefore, mandatory to assess the toxic metals in such crops and vegetables. In this regard, samples of corn, millet, cabbage, spinach and potato were collected within the vicinity of industrial areas of the Faisalabad and Gujranwala regions. The food samples were analyzed using neutron activation analysis (NAA) technique. The highest concentration values of Arsenic (1.9 ± 0.1 μg/g) and Cobalt (0.85 ± 0.01 μg/g) were found in cabbage whereas Manganese (91.6 ± 0.2 μg/g), Antimony (0.15 ± 0.03 μg/g) and Selenium (1.1 ± 0.1 μg/g) were observed in spinach and Chromium (9.63 ± 1.3 μg/g) was found in millet crop. The observed concentrations of all the toxic and heavy metals in crops and vegetables are higher than those reported in the literature.

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Abstract  

Pakistan is an agricultural country, yet it is facing a serious threat due to the shortage of water resources and degradation of the agricultural land by the pollution of industrial effluents. A limited number of the current industries are equipped with proper operating treatment plants. Generally, the untreated effluents are disposed off to the open environment which is used for irrigation purposes. Therefore, vegetables and crops grown around the industrial areas is a major potential source of metal poisoning which pose a serious risk to the general public. Hence, study of the toxicity level in vegetables and crops is highly desirable. In this regard, systematic studies have been carried out to determine concentration levels of toxic elements in the samples of vegetables, crops, effluents and soil collected from the industrial areas of the Faisalabad. After processing, these samples were analyzed using neutron activation analysis and atomic absorption spectrometric techniques. The highest concentrations of toxic metals were observed for As (2.73 ± 0.34) in cabbage, Cd (1.5 ± 0.1), Ni (5.1 ± 0.9) and Pb (4.3 ± 0.2) in corn, Co (0.65 ± 0.02), and Sb (0.09 ± 0.01) in carrot, Cr (9.63 ± 1.3), Mn (46.5 ± 4.2) and Se (1.03 ± 0.1) in millet, Cu (11.3 ± 1.1) in tomato vegetables and crop samples. Although, the observed toxicity levels in vegetables and crop samples were higher than those grown in non-industrial areas, yet these toxicity levels are within the safe recommended limits.

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Summary  

The deposition of trace and major elements from the atmosphere to the ground is an important factor for plants, animals and humans as well. Total suspended particulate matter was measured by a standard gravimetric technique. A scanning electron microscope was used for the evaluation of the size distribution and morphological structures of the aerosol particulates trapped on the surface of filter paper. The aerosol particulates were studied by a scanning electron microscope at various magnification. The trace elemental composition in the atmosphere of Faisalabad was studied by using instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS). Concentrations of 23 trace elements and a major one were determined in samples of aerosol particulates collected during a longe sampling period in the atmosphere at Faisalabad, Pakistan. Their amount was two times higher than the limits adopted by the U.S. Environmental Protection Agency for the urban environment.

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Abstract  

The k 0 method has been introduced at the 30 kW miniaturized neutron source reactor (MNSR) at the Pakistan Institute of Nuclear Science & Technology (PINSTECH). It involved the full energy peak efficiency calibration of the HPGe detector for different counting geometries and the characterization of the neutron flux at four inner irradiation channels. The latter involved the determination of the thermal to the epithermal flux ratio, epithermal flux shape factor, the modified spectral index, Westcott’s g-factor, the Maxwellian neutron temperature and the fast flux. The method was validated by analyzing IAEA-SL1 (Lake Sediment) and NIST-SRM-1572 (Citrus Leaves) reference materials. All calculations were performed in Excel, including the optimization step. The results revealed that most of the elements were estimated with less than 10% relative deviation from the certified value.

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Abstract  

The indiscriminate discharge of untreated industrial effluents and solid wastes into the open environment poses a serious threat to the ecosystem. Gujranwala is an industrial city of Pakistan wherein a large number of different industries are situated and majority of them are not equipped with proper recycling or effluent treatment plants. Unfortunately, untreated industrial effluents are locally used for the irrigation purposes which may result in higher concentrations of toxic metals in the crops and vegetables. Therefore, prime objective of the present study was to determine concentrations of toxic metals in the polluted soils, vegetables and crops grown in the vicinity of industrial areas using neutron activation analysis technique. The results obtained showed higher values of toxic metals in the studied samples. The observed highest concentration of As (0.94 ± 0.06) in spinach, Br (69 ± 9) in turnip, Co (0.83 ± 0.01) in millet, Cr (51.7 ± 4.2) in wheat, Mn (76.2 ± 7.3) in tomato, Sb (0.5 ± 0.06) in rice, Cl (31698 ± 3921) and Se (3.4 ± 0.4) in carrot. These values are higher than those reported in the literature.

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