Statistical and Geospatial Assessment of Groundwater Quality in the Megacity of Karachi

Inserting Groundwater quality variability and sources potentially contributing to aquifer recharge was evaluated in metropolitan Karachi. Selected sampling sites were characterized by large waste dumping sites, industrial zones, and the presence of open streams receiving heavy loads of industrial and domestic wastes. Levels of pH, electrical conductivity (EC), fluoride (F-), chloride (Cl-), bromide (Br-), nitrate-N (NO-3-N), sulfate (SO2-4), sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), and ammonium (NH+4) were determined and compared with the WHO permissible limits. Concentrations of the measured ions were in the order of Cl- > Na+ > SO2-4 > Mg2+ > Ca2+ > NO-3-N > K+ > F- > Br-. EC values were above the WHO guidelines, representing the presence of high ionic concentration in the groundwater. The health risk index (HRI) for indicated that inhabitants of Karachi are at risk of high exposure. Ingestion of high concentrations of NO-3-N in water can cause methemoglobinemia and birth defects. Results of multivariate statistical analysis, principal component analysis (PCA), cluster analysis (CA), and geographic information system (GIS) map analysis revealed that human activities are leading to adverse effects on the existing groundwater quality in Karachi.

Monitoring of Environmental Mercury Exposure Using Hair as Bioindicator and the Study of Potential Factors Affecting on It in Karachi

The World Health Organization (WHO), Environmental Protection Agency (EPA), and International Atomic Energy Agency (IAEA) have recommended the use of hair for worldwide environmental monitoring. Mercury exposure to the inhabitants of Karachi was assessed by using hair as bioindicator. Hair samples of 200 residents of Karachi were collected and analyzed through cold vapor atomic absorption spectroscopy (CVAA) technique for mercury concentration. The effects of age, gender, working status, location, food and smoking habit were investigated. Control region showed a positive correlation between HHg and age of donor while no such correlation was observed for polluted regions. Mercury exposure through cosmetic usage in female was only pronounced in control region. These results indicate that environmental pollution dominates other potential factors. Age and smoking habit were not found to be the influencing factors while an elevated mean level of mercury was noticed for regular fish consumers than rarely fish consumers. 95.33% of the samples contained HHg greater than the permissible level of 2 μg?g?1 set by WHO. An apparently healthy male donor had HHg concentration (28.24 μg?g?1) closer to the high risk concentration of 30 μg?g?1 based on WHO criteria. Whereas, two female donors of the age group of 41-50 years had HHg concentrations (10.82 and 11.84 μg?g?1) higher than the NOAEL (no observed adverse affects level) value (10 μg?g?1) for females which is associated with fetus neurotoxicity. However, no symptoms of mercury toxicity were visible. The results indicate the alarming condition of pollution in the city which should be taken into further consideration.

Coal Chemistry and Morphology of Thar Reserves,Pakistan

The surface of Thar coal has been characterized by spectroscopic, microscopic and chemical methods using atomic absorption spectroscopy, fourier transform infrared analysis, X-ray diffraction, scanned electron microscopy and pH titration. The samples contained high moisture, low volatile and low to moderate sulfur content and ranked as lignite (heating value 2541 - 4289 btu/lb on moist, mineral-matter-free basis). Scanned electron micrographs show porous matrix with calcium, potassium or sodium minerals. Fourier transform infrared analysis confirmed the presence of aluminum, silica and hydrate mineral constituents also. The spectra showed C=C aromatic groups at 1604 - 1609 cm-1. Phenolic ester and carboxylic acid are identified by C=O stretching vibration peaks at 1702 cm-1. The peaks of quartz and kaolinite were observed at 900 - 1100 cm-1. Point of zero charge of Thar coal has been estimated as 6.00 to 6.27 through adsorption of H+ and OH- ions by suspending coal particles in aqueous electrolyte solution. Oxygen containing functional groups, mineral matter, and metal oxides are found to have a remarkable impact on point of zero charge. The surface characterization study will be helpful in the separation of hydrophilic impurities during coal preparation processes considering pzc as the controlling

Study of Physicochemical Parameters of Rainwater: A Case Study of Karachi, Pakistan

The urban centers of developing countries like Karachi city in Pakistan are facing the menace of air pollution and atmospheric wet deposition can be used as a tool for monitoring the quality of air. In this study, rainwater samples from eighteen different towns of Karachi were collected during monsoon season (July to September, 2013) in triplicate and analyzed. Their pH (range 6.2 - 7.9), electrical conductivity (range 0.02 - 0.21 m·S/cm), total dissolved solids (range 32 - 159 mg/l), dissolved oxygen (range 6.3 - 8.2 mg/l) and hardness (23 - 89 mg/l) were immediately monitored within next twenty four hours of sample collections. The samples were then acidified and analyzed for the presence of major cations ammonium, sodium, potassium, magnesium and calcium by flame atomic absorption spectroscopy and flame emission spectroscopy. The anions fluoride, chloride, nitrate, carbonate and sulphate were analyzed by ion chromatography. The results of the analysis were compared with the values provided by WHO guidelines in order to access the quality of water. Most of the rainwater samples were completely free from considerable pollution and meet the WHO standard values. However, in Lyari, Gulshan, Shah Faisal, Landhi, Malir and Gadap town the concentration of Mg2+ and in North Nazimabad, Korangi, Gulshan, Saddar, Lyari, SITE and Keamari town the concentration of?N3- is above the WHO standards, indicating their presence from air pollution.

Hollow fiber-based liquid phase microextraction followed by analytical instrumental techniques for quantitative analysis of heavy metal ions and pharmaceuticals

Hollow-fiber liquid-phase microextraction(HF-LPME)and electromembrane extraction(EME)are miniaturized extraction techniques,and have been coupled with various analytical instruments for trace analysis of heavy metals,drugs and other organic compounds,in recent years.HF-LPME and EME provide high selectivity,efficient sample cleanup and enrichment,and reduce the consumption of organic sol-vents to a few micro-liters per sample.HF-LPME and EME are compatible with different analytical in-struments for chromatography,electrophoresis,atomic spectroscopy,mass spectrometry,and electrochemical detection.HF-LPME and EME have gained significant popularity during the recent years.This review focuses on hollow fiber based techniques(especially HF-LPME and EME)of heavy metals and pharmaceuticals(published 2017 to May 2019),and their combinations with atomic spectroscopy,UV-VIS spectrophotometry,high performance liquid chromatography,gas chromatography,capillary elec-trophoresis,and voltammetry.

Cure Characteristics, Mechanical and Swelling Properties of Marble Sludge Filled EPDM Modified Chloroprene Rubber Blends

In the present study, attempts have been made to modify Marble Sludge (MS) filled Ethylene-propylene-diene monomer (EPDM) with Chloroprene rubber (CR). Compounding was carried out on a two-roll mill and vulcanized at 155℃. The modified blend of MS filed EPDM/CR was characterized on the basis of the effect of blend ratio on cure characteristics, mechanical and swelling properties of blends were investigated. The effect of thermal aging on mechanical and swelling behavior in aromatic, aliphatic and chlorinated solvents of cured MS filled EPDM/CR blend was also examined. The minimum torque and maximum torque of the blend first increased and then slightly decreased after the increasing of CR content in MS filled EPDM/CR blends. Scorch time, cure time, cure rate index, tensile strength, tear strength, hardness increased with increasing CR content in the MS filled EPDM compound, but elongation at break, resilience, abrasion loss, mole % uptake, swelling index and percentage of soluble fraction decreased, resilience, abrasion loss, mole % uptake, swelling index and percentage of soluble fraction decreases. Accelerated aging performance of cured composites also influenced by increasing CR content in MS filled EPDM compound.

Optimization of Quantitative Analysis of Naproxin Sodium Using UV Spectrophotometery in Different Solvent Mediums

A new rapid, simple and reproducible UV spectrophotometric method was developed and validated for the estimation of Naproxen Sodium (NpSd) in bulk and pharmaceutical formulation. The quantification of NpSd was done at 230 nm in methanol and in buffer of pH 6.8 and 9. Beer’s law was obeyed in the concentration range of 4 - 36 (r2 = 0.999) in methanol and 5 - 25 μgmL﹣1 in buffer of pH 6.8 and 9 (r2 = 0.988 and 0.997) respectively. The apparent molar absorptivity values were also calculated in all mediums. All parameters according to ICH guideline were tested and validated. The detection and quantitation limits were found to be 0.054, 0.083, 0.073 and 0.181, 0.251, 0.211 μgmL﹣1 respectively. These methods were applied directly to the analysis of the pharmaceutical tablet preparations (Anex? tablet 250 mg). The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation 3%), while being simple, cheap and less time consuming and hence can be suitably applied for the estimation of NpSd in dosage forms and dissolution studies.

Kinetics and mechanisms of oxidation of d-fructose and d-lactose by permanganate ion in acidic medium

The oxidations of D-fructose and D-lactose were monitored spectrophotometrically by potassium permanganate in acidic medium at λmax 545 nm. Reaction demonstrated that the two oxidative species of permanganate were involved in an acidic oxidation of the sugars. It was established that respective acids of sugars as well as arabinonic and formic acid were the oxidation products. Respective acids of sugars were the results of reactive oxygen species of permanganate ions in acidic conditions while arabinonic and formic acids due to the cleavage of C__C bond through MnO-4 species. It was first order kinetics with respect to [MnO-4 ], [fructose], [lactose] and [H+]. Hg was used to accelerate the slow oxidation of lactose. Effect of varying salt electrolyte concentration was insignificant showing that the molecular species was involved in the rate determining step. Formic and arabinonic acids and respective acids were analyzed through spot and spectroscopic studies respectively. Reaction was monitored at different temperatures and thermodynamics activation parameters were determined. A mechanism consistent with kinetic studies, spectral evidences, stoichiometry of the reactions and product analysis has been proposed for the oxidation of fructose and lactose in absence and presence of catalyst respectively.

TGA-DSC: A Screening Tool for the Evaluation of Hydrocracking Catalyst Performance

DSC-TGA was used for screening of commercially available and synthesized catalyst for the degradation of polypropylene (PP). In this study, all the runs were performed with 50% load of the catalyst and the results were compared with those of PP + 50% pure silica having no catalytic activity. The degradation behavior of PP using catalyst Zeolyst-713 exhibited much higher degradation activity among the other catalysts used in this study. Moreover, it contributed to lowering of initial stage temperature showing a shape-selective effect. DSC-TGA tools such as Ton, Tmax, T99%, activation energy, enthalpy change in the process and coke content were used for screening. It was concluded that the pore construction and unique acid properties of the Zeolyst-713 as well as proper reaction temperatures were significant influential factors to fully exert this effect. In this work, kinetics of catalytic thermogravimetric degradation of PP used for domestic purposes was investigated using Alumino-silicate catalyst. Zeolyst-713 was observed to lower activation energy and enhances degradation activity in comparison with thermal degradation without a catalyst.

Simultaneous Determination of Amlodipine with H₁-Receptor Antagonists by Reversed Phase High Performance Liquid Chromatography and Application to Interaction Studies

A rapid, fast and precise method has been developed and validated for the simultaneous determination of amlodipine with H1-receptor antagonists (cetirizine, fexofenadine, and buclizine) from dosage forms. The chromatography was performed on a Purospher? Star, C18 (5 mm, 250 × 4.6 mm) column using acetonitrile: buffer (0.01 mM) (40:60, v/v, pH adjusted to 3.0), as a mobile phase. The mobile phase was pumped at a flow rate of 1.0 mL·min-1 and UV detection was performed at 240 nm. The method was validated for linearity, accuracy, precision and specificity. The method was applied to study the interaction between amlodipine and H1-receptor antagonists. These interactions were carried out in simulated gastric juice (pH 1), simulated full stomach (pH 4), blood pH (pH 7.4) and simulating GI (pH 9). The interacting drugs were heated at 37℃ with intermit-tent shaking and the samples were withdrawn every thirty minutes for three hours and drug contents were analyzed by RP-HPLC techniques. In most cases the in vitro availability of amlodipine was decreased. It was observed that the change in in vitro availability was pH dependent.

An Ultra-sensitive LC Method for the Simultaneous Determination of Paracetamol, Carbamazepine, Losartan and Ciprofloxacin in Bulk Drug, Pharmaceutical Formulation and Human Serum by Programming the Detector

An ultra-sensitive LC method for the simultaneous quantitation of paracetamol, carbamazepine, losartan and ciprofloxacin have been developed and validated following the ICH guidelines at isobestic point and by programming the detector at individual wavelength of each component. The components were eluted by 50:50 v/v acetonitrile-water (pH 3.0) using a Bondapak, C18 (10 μm, 25 × 0.46 cm) column at flow rate of 1.0 mL·min-1 with detection wavelength 240 nm at isobestic point and 245, 230, 206 and 272 nm for paracetamol, carbamazepine, losartan potassium and ciprofloxacin respectively by programming the detector. Linearity was found to be 0.5 - 24, 0.25 - 8.0, 0.4 - 12 and 0.75 - 10 μg·mL-1 (R2 > 0.999) with detection limits 99, 20, 30 and 6.0 ng·mL-1 respectively. Comparison study with time program method showed more sensitivity with calibration range of 0.4 - 12, 0.2 - 6.0, 0.1 - 3.0 and 0.25 - 8.0 μg·mL-1 (R2 > 0.999) and LOD values 29, 11, 2.0 and 5.0 ng·mL-1 respectively. Percent recoveries >98.37% from pharmaceutical formulation and human serum samples and RSD 2% for inter-day and intra-day assay were obtained. The method was found to be robust and can be successfully applied for the determination of studied drugs in, pharmaceutical formulations and human serum without interference of excipients or endogenous components of serum.

The Role of Trace Metals and Environmental Factors in the Onset and Progression of Schizophrenia in Pakistani Population

Exposure to toxic chemicals appears to be one of the major factors in the onset of Schizophrenia. Present study was designed to find out the association of socio-economic, clinical and heavy metals such as chromium (Cr), lead (Pb) copper (Cu), zinc (Zn), iron (Fe), manganese (Mn) selenium (Se) and arsenic (As) as the principle environmental factors that appear to impact schizophrenic condition in Pakistani population. In this study we have tried to expose some factors such as drug abuse, marital status, education, monthly income that could be related to the disease. These parameters were not investigated before in Pakistani subjects. A self-made questionnaire was developed to collect and record the history of patient’s social and economical status. The level of transition metals in the whole blood was also measured by using Inductive couple plasma optical emission spectroscopy (ICP-OES). Present study has found higher levels of Cr, Pb, Zn, Se, As and Cu and lower levels of Fe and Mn in the blood of newly diagnosed (ND) patients when compared to the controls. While comparing ND with the patients who were on medication (Old Diagnosed) we, found lower level of these metals except for copper in ND. However no significant differences were observed between any trace metal levels between the studied groups. The survey concludes that economic status, marital status and illegal drugs are significantly associated with schizophrenia. Pakistani men who use cannabis are significantly higher in numbers when compared to women in acquiring the psychiatric symptoms.

Investigation of Iron Complex Formation of Anti-Hypertensive Drug: Methyldopa

The drug administered for any disease may play an unwanted function in biological system. They may have multiple counter effects, one of which is their interaction to bioactive metals. Iron is most common bio essential metal and is reported to interact with antihypertensive drug methyldopa. In the present study, above said complex is analyzed by UV-Visible spectrophotometry. Formation constant of the complex is calculated by using mole ratio method and single point statistical method which is in the range of 1010, values are also calculated which are independent of pH like formation constant. Absorbance maxima were found to be dependent on pH. At lower pH complex shows two broad bands centered at 430 nm and 730 nm. With the rise in pH later peak shifts toward lower wavelength, so 615 nm is selected for further studies. Molar extinction coefficient of the complex is explored by serial dilution method. At all wavelengths it increases with increase in pH. Mole ratio and slope ratio methods are used for exploring stoichiometry. Metal to ligand combining ratio in the complex is 1:2 at pH 4.0 and pH 4.5 while 1:3 at pH 5.0 and pH 5.5.

Optimization of Electrocoagulation Process for the Removal of Binary Dye Mixtures Using Response Surface Methodology and Estimation of Operating Cost

The study was useful for the treatment of Reactive red 223 (R223) and Coomassie brilliant blue R250 (CBBR250) binary dye system by electrocoagulation process (EC). Moreover, the Al and Fe electrode were used as an anode and cathode, respectively. The response surface methodology (RSM) was adopted by utilizing central composite design to plan the experimental runs. The EC process was preceded under the effect of operating parameters including pH, NaCl, voltage and electrolysis time. The % color and COD removals were examined as response variables. The removal efficiency of RR223 and CBBR250 dye at optimum values was 89% and 94% and COD removal was 100%. The kinetic study was performed to determine the rate and rate constant. First and second order kinetic models were studied to figure out the exact mechanism of the dye removal using EC process. The estimated cost of the experimental design about 4.486 US$/dm3 was also determined. This study showed that EC process is an economical way for the treatment of waste water.

Simple Quantitation of Flucytosine in Low Volume Serum Samples and Evaluation of Common Endogenous Interferences by HPLC-UV

5-Fluorocytosine (5-FC) is used for the treatment of several infections. It is extremely important to monitor blood level concentration for maximum activity to avoid its side effects. A simple, faster, and more accurate analytical method is developed and validated using high-performance liquid chromatography with UV detection in a very low-volume serum sample. Exactly 50 μL of serum was precipitated with 5% trichloroacetic acid. After mixing and centrifugation, 20 μL of supernatant was injected into the HPLC column. Detection was performed at 280 nm. The method is very specific and free from interfering substances due to different drugs and their different circulating metabolites. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.50 μg/L and 1.0 μg/L, respectively. The method was linear in the range of 5 - 150 μg/L in the serum sample. In method comparison, the correlation coefficient r2 was 0.999 and the percentage recovery was 90% - 105% on four levels of the quality control samples. Within run and between run precision was found to be less than 2.2% at four different concentrations (5, 25, 50, and 100 μg/L). A simple, faster, and more accurate HPLC-UV method is developed which is very useful for monitoring 5-FC concentration in low volume serum samples without evaporation step and ion exchange chromatography within minutes.

Synthesis and antibacterial studies of ciprofloxacin-metal complexes

Metal complexes of ciprofloxacin were synthesized to study the effect of the drug on the metals present in the body or metals co-administered as multivitamin therapy. These complexes were then characterized by IR, UV, 1 H NMR, CHN and AA analyses. It was found that the metals coordinated through the β-keto carboxylic group, forming four coordinated complexes having square planar geometry. The effect of the antibacterial activity of these complexes with respect to parent drug was also studied against 14 different Gram + ve and Gram – ve organisms by the disk susceptibility technique. Some complexes showed improve activity as compared with the stated drug.

Kinetics of Reduction of Thionine with Ribose and the Structural Properties of the Dye at Different pH Using DFT Method

The reaction between the thionine （Th） and the ribose was observed spectrophotometrically and changes in absorbance of Th were recorded at variable concentration of dye, reductant and pH. A pseudo first order rate of reaction was found to establish the reduction kinetics of the dye, studied at a pH range of 0.34 to 12.8. Absorption spectrum of Th at different pH, with ribose showed a pH （12.8） dependent introversion. The reduction most probably took place with enediol intermediate of the sugar at high pH. A full geometry optimization of predominant species of Th namely, mono-deprotonated, di-deprotonated Th, and LTh （leuco thionine） respectively, at low and high pH, was performed at B3LYP level of theory. The data obtained from the energy minimization were in excellent agreement with other experimental and theoretical observations. The calculated enthalpies of formation for both reduction reactions （mono-deprotonated Th＋H＋→leucothionine and di-deprotonated Th＋2H＋→leucothionine） provided evidences for maximum reduction of the dye at high pH.

Spectrokinetics study of probable effects of diverse inorganic ions on bleaching of dye

Toluidine blue(TB)is an important anticoagulant metachromasia molecule showing a pronounced variation in the visible spectrum due to the aggregation phenomenon and electrostatic interaction with the charged synthetic and biologic polymers.The current study describes the interactive role of diverse inorganic material ions on the bleaching of toluidine blue(tolonium chloride)(TB^(+))with urea in acidic and basic media using the spectrophotometric technique.The spectra of TB and urea with different cations and anions were monitored and their characteristic features are presented here.The negative effect of added cations on reduction may be the result of altered electron pathways which led to suppression of the reduction/bleaching of TB,while a slight decrease in dye reduction by added anions may be due to the scavenging of the OH*radical.It has been observed in the case of Co^(2+)that in addition to the electron-transfer reaction,other processes like layer and precipitate formation also appear to be taking place.The dye bleaching process followed pseudo first order kinetics with respect to TB,urea,and H^(+)ion,whereas significant decoloration in the presence of urea proved that reductants control the redox reaction.No decoloration in acidic medium with diverse ions was seen compared to alkaline media,showing that water pH played an important role in the bleaching of dye.The reduction/bleaching of dye was investigated at different temperatures,and energy parameters were evaluated for a TB^(+)-Urea reaction,including the energy of activation(Ea=39.60 kJ·mol^(–1)),enthalpy of activation(ΔH#=34 kJ$mol^(–1)),entropy of activation(ΔS#=146.5 kJ mol^(–1)·K^(–1)),and free energy of activation(ΔG*=–52.35 kJ·mol^(–1)).A mechanism of interaction of diverse ions in dye bleaching and a mechanism of reduction based on the above findings is proposed.

The kinetics study of the reduction of Fast Green dye with cetylpyridinum chloride as cationic surfactant

The kinetics of the reaction of Fast Green dye(FG)with cetylpyridinum chloride was studied in alkaline medium by UV-Visible spectrophotometer.Reduction of Fast Green dye was carried out by varying the fast green dye concentration,cetylpyridinum chloride concentration and concentration of sodium hydroxide.In the present study the reduction of dye was carried out in order to reduce the color content.The interaction of dye was carried out with reducing analyte(cetylpyridinum chloride).The rate of the reaction was determined by varying the above parameters at different temperatures.It was observed that the reduction followed pseudo first-order kinetics with respect to dye,surfactant,OH–ion concentration according to the following reaction pathway.reaction like entropy of activation(ΔS)and free energy of activation(ΔG)showed the extremely solvated states of transient complex which was less disorderly arranged than the oxidized form of dye,whereas Ea values reflects a high amount of energy required for the reduction of dye with cetylpyridinum chloride.

Effect of foreign ions for the determination of metal ion in the presence of surfactants

Aluminum is the third most abundant metal in the Earth’s crust.Despite its ubiquitous nature it is present in small amount in living organisms.Aluminum toxicity has been implicated in the pathogenesis of renal distinct clinical syndromes,including progressive and fatal encephalopathy and bone diseases.In the present study,Al was selected for the analysis by complexometric method.This method was based on the formation of a red colored ternary complex by the reaction of Aluminum with Aluminon(Aurin tricarboxylic acid triammonium salt)in the presence of micellar medium.The ternary complex of Aluminum with the surfactant Triton X-100 shows a maximum absorbance at 530 nm wavelength at pH 4.0 while with the sodium dodecyl sulfate it shows a maximum absorbance at 525 nm and at pH 5.0.The reaction was proceeded by the variation in pH and concentrations of surfactants,aluminon,aluminum.Their effects on the reaction of aluminum with aluminon complex in micellar media were recorded by UV-visible spectrophotometer.The reaction was found to be extremely rapid at room temperature.The system obeys Lambert Beer’s law between 0.24 and 21.74μg/mL concentrations with Triton X-100.The values of slope,intercept and correlation coefficients were 0.07,0.348 and 0.989,respectively.The concentration varied between 0.24 and 24.14μg/mL with sodium dodecyl sulfate and the values of slope,intercept and correlation coefficients were 0.029,0.148 and 0.962,respectively.The foreign ion effect was also tested by keeping the constant concentration of metal ion and determining its concentration in the presence of different foreign ions.The method was also applied for the determination of Al(III)in pharmaceutical formulations and water samples,which showed an excellent resemblance between reported and obtained results.