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  • Author or Editor: N. Siddique x
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Abstract  

Over a 1,000 pairs of coarse and fine filters were collected using Gent samplers and polycarbonate filters from three sites in Islamabad from the period 1998 to 2010. The black carbon in these samples was determined by reflectance measurement while their elemental composition were determined using the techniques of instrumental neutron activation analysis, ion beam analysis and X-ray fluorescence spectrometry. Islamabad is a well planned and relatively small city as compared to Lahore or Karachi therefore its air quality is better than the air quality of other major Pakistani cities. It was found that the new air quality standards being implemented by the Pakistani government on the 1st of January 2012 may not be attained even in Islamabad without the implementation of control and remedial measures. An overview of the elemental data obtained and calculation of enrichment factors shows that the particles in Islamabad originate from re-suspended soil, vehicular emissions and coal combustion. However further work is required for identification of pollution sources and their origin.

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Abstract  

Tuna fish flesh homogenate, IAEA-436, was received under the IAEA Analytical Quality Control Services (AQCS) intercomparison programme. Instrumental neutron activation analysis (INAA) was used to determine Al, As, Br, Ca, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hg, K, Mg, Mn, Na, Rb, Se, Sb, Sm, and Zn in this proposed reference material (RM). IAEA-407 (Fish Homogenate) and NIST-SRM-1572 (Citrus Leaves) were used for quality assurance (QA) purposes. Due to the very low levels of most elements in IAEA-436, large discrepancies were observed between our results for IAEA-436 and data cited by the IAEA.

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Summary  

A national intercomparison exercise was conducted to remove inconsistencies and improve analytical procedures in the measurement of hafnium and zirconium in zirconium ores. The ZH-A series of reference samples, prepared at the Pakistan Institute of Nuclear Science and Technology (PINSTECH), were used for this purpose. It was observed that measurement errors decreased with increasing Hf concentration (~298-17500 ppm) for most techniques, especially for AAS due to the sample preparation procedure required for this technique. Of all the tested techniques most reliable results were obtained with neutron activation analysis (NAA) for the measurement of Hf and Zr in such matrices.

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Abstract  

The rare earth elements (REEs) content of Kakul phosphate rock (PR) from different localities of the main Hazara deposits of Pakistan were determined using instrumental neutron activation analysis (INAA). 25 phosphorite samples were collected from different phosphorite sites and 6 samples representing different batches from the crushing plant near Kakul Mine. Concentrations of seven REEs (Ce, Eu, La, Lu, Sm, Tb and Yb) were determined in the PR samples. The highest amounts of Heavy and light rare earth elements (HREE and LREE) were quantified in the PR samples collected at the Phosphate Rock Crushing Plant while the lowest amounts of these REEs were measured in the Lambidogi Phosphorite deposit samples. Comparison with global data showed the REEs content of the studied PRs show lower range for all REEs and mostly comparable to the data reported by Israel and Syria. Calculated chondrite ratio for these elements depicts enrichment of LREEs in all phosphorite deposits.

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Abstract  

instrumental neutron activation analysis (INAA) has been employed to determine 19 essential and other trace elements of fourteen fruits harvested in Pakistan. Most of the fruits investigated contain substantial Ca, Cl, Fe, Mg, K and Na concentration levels. Fruits were found to be an adequate source of Co and Fe. Winter season provides a variety of fruits with highest adequacy for most of the essential elements while the fruits ingested in the summer season provide the minimum nutrient adequacy for these elements with the exception of Cl.

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Abstract  

Instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectroscopy methodology was developed to characterize the hazardous and other inorganic trace element constituents in new and used domestic plastic food containers. INAA due to its non destructive, highly sensitive, multielement and low detection limits characteristics was found to be a good technique for the characterization of polymeric products. Through the variation of irradiation, cooling and counting protocols Al, Ba, Br, Co, Cr, Eu, Fe, Hg, K, Mn, Na, Nd, Sb, Sc, Th, Ti, V and Zn were determined, while Atomic Absorption Spectroscopy was used as complementary technique to quantify toxic inorganic elements such as Cd, Pb and Cu. These elements are thought to originate from the polymer manufacturing processes. It was found that there was gradual increase in the concentration of most of these elements from new to used plastic samples. Moreover it was also observed that these inorganic elements are present in higher concentrations in the lower grade containers as compared to the high quality containers. It was also observed that the good quality containers even with the long usage do not degrade to such an extent as the low quality containers.

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Abstract  

Sensitive nondestructive instrumental neutron activation analysis (INAA) technique has been applied for the determination of rare earth elements (REEs) (Ce, Eu, La, Lu, Sm, Tb and Yb) in phosphate rocks (PR) and granulated single super-phosphate (GSSP) fertilizer samples from Hazara district of Pakistan. The comparison of the PR with product fertilizers shows that most of the quantified REEs were found to be in lower contents in the fertilizers. Six fertilizer samples with different N, P and K ratio for distinctive application to plants were also characterized. The REEs in these showed irregular patterns that can be attributed to difference in their manufacturing and chemical processes. The REEs contents of local phosphate fertilizer were found to be lower in comparison to the values cited in the literature; however Ce is relatively high. For quality assurance fair agreement was found between the results obtained for reference materials IAEA SL-1 (Lake Sediment) and GSJ-JR-1 (Rhyolite).

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Abstract  

INAA and AAS techniques have been employed to determine 40 elements in soil of a municipal waste dump in sector H-11, Islamabad. Background soil was also analyzed to study the extent of contamination of the dump site soil. Most of the major elements in these soils represented the geochemical composition of the soil in this area. The enrichment factors for quantified elements identified high Sb and Mg contents that could be attributed to the presence of PET and food materials in the waste. Geo-accumulation Index (I geo), Pollution Index (PI) and the Integrated Pollution Index (IPI) have also been calculated for all elements. The values for these indices show that municipal waste has distorted the soil ambiance and the soil of waste dump site is slightly to moderately polluted as compared to the background soil. The dump soil was found to be moderately polluted by the elements Ba, Br, Ga, Rb, Zn, Ni and Pb. Significantly high Cu, Mg and Sb contamination was observed for the waste soil that is likely to pose an environmental issue if current waste disposal procedures are continuously employed.

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Synthetic seed technology is an alternative to traditional micropropagation for production and delivery of cloned plantlets. Synthetic seeds were produced by encapsulating nodal segments of C. angustifolia in calcium alginate gel. 3% (w/v) sodium alginate and 100 mM CaCl2 · 2H2O were found most suitable for encapsulation of nodal segments. Synthetic seeds cultured on half strength Murashige and Skoog medium supplemented with thidiazuron (5.0 μM) + indole-3-acetic acid (1.0 μM) produced maximum number of shoots (10.9 ± 0.78) after 8 weeks of culture exhibiting (78%) in vitro conversion response. Encapsulated nodal segments demonstrated successful regeneration after different period (1–6 weeks) of cold storage at 4 °C. The synthetic seeds stored at 4 °C for a period of 4 weeks resulted in maximum conversion frequency (93%) after 8 weeks when placed back to regeneration medium. The isolated shoots when cultured on half strength Murashige and Skoog medium supplemented with 1.0 μM indole-3-butyric acid (IBA), produced healthy roots and plantlets with well-developed shoot and roots were successfully hardened off in plastic pots containing sterile soilrite inside the growth chamber and gradually transferred to greenhouse where they grew well with 85% survival rate. Growth performance of 2 months old in vitro-raised plant was compared with in vivo seedlings of the same age. Changes in the content of photosynthetic pigments, net photosynthetic rate (PN), superoxide dismutase and catalase activity in C. angustifolia indicated the adaptation of micropropagated plants to ex vitro conditions.

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