Amir Waseem

Pollution Status of Pakistan: A Retrospective Review on Heavy Metal Contamination of Water, Soil, and Vegetables

Trace heavy metals, such as arsenic, cadmium, lead, chromium, nickel, and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. In addition to these metals, copper, manganese, iron, and zinc are also important trace micronutrients. The presence of trace heavy metals in the atmosphere, soil, and water can cause serious problems to all organisms, and the ubiquitous bioavailability of these heavy metal can result in bioaccumulation in the food chain which especially can be highly dangerous to human health. This study reviews the heavy metal contamination in several areas of Pakistan over the past few years, particularly to assess the heavy metal contamination in water (ground water, surface water, and waste water), soil, sediments, particulate matter, and vegetables. The listed contaminations affect the drinking water quality, ecological environment, and food chain. Moreover, the toxicity induced by contaminated water, soil, and vegetables poses serious threat to human health.

Flow‐injection determination of cysteine in pharmaceuticals based on luminol–persulphate chemiluminescence detection

A flow injection (FI) method is reported for the determination of l-cysteine, based on its enhancement on chemiluminescence (CL) emission of luminol oxidized by sodium persulphate in alkaline solution. The calibration graph was linear over the range 1.0 x 10(-9)-5.0 x 10(-7) mol/L (r(2) = 0.9992), with relative standard deviations (RSDs) in the range 1.1-2.3% (n = 4). The limit of detection (3 sigma blank) was 5.0 x 10(-10) mol/L with a sample throughput of 120/h. The method was applied to pharmaceuticals and the results obtained were in reasonable agreement with the amount labelled. The proposed method was also applied to cysteine in synthetic amino acid mixtures. Calibration graphs of N-acetylcysteine and glutathione over the range 1.0-50 x 10(-8) and 0.5-7.5 x 10(-7) mol/L were also established (r(2) = 0.998 and 0.9986) with RSDs in the range 1.0-2.0% (n = 4), and the limits of detection (3 sigma blank) were 5.0 x 10(-9) and 1.0 x 10(-8) mol/L, respectively.

Determination of thiram in natural waters using flow-injection with cerium(IV)-quinine chemiluminescence system.

A simple and rapid flow-injection chemiluminescence method has been developed for the determination of dithiocarbamate fungicide thiram based on the chemiluminescence reaction of thiram with ceric sulfate and quinine in aqueous sulfuric acid. The present method allowed the determination of thiram in the concentration range of 7.5-2500 ng/mL and the detection limit (signal-to-noise ratio = 3) was 7.5 ng/mL with sample throughput of 120/h. The relative standard deviation was 2.5% for 10 replicate analyses of 500 ng/mL thiram. The effects of foreign species including various anions and cations present in water at environmentally relevant concentrations and some pesticides were also investigated. The proposed method was applied to determine thiram in spiked natural waters using octadecyl bonded phase silica (C(18)) cartridges for solid-phase extraction. The recoveries were in the range 99 +/- 1 to 104 +/- 1%.

Water quality assessment of the River Kabul at Peshawar, Pakistan: Industrial and urban wastewater impacts

Untreated wastewater discharges may have significant short term and long term effects on the quality of a river system. Present study was undertaken to assess the present status of the water quality of the River Kabul near Peshawar in Pakistan. Seven sites were sampled upstream and downstream in the River Kabul in 2009. Samples were also taken from waste water channel (Budni Drain) that carries waste-water of Peshawar Industrial Estate as well as the domestic sewers to assess the pollution contribution of these sources to the River Kabul. Physico-chemical and microbiological parameters of the samples were analyzed during the study, as well as possible sources of contamination were investigated. The study showed that the pollution level in river is rising from upstream (at city entrance) to downstream (at city exit) due to discharge of domestic waste water effluents, agricultural activities, and solid waste dumping directly into the river.

Flow injection determination of thyroxine in pharmaceutical preparations using tris(2,2'-bipyridyl)ruthenium(III)-NADH chemiluminescence detection.

A flow injection (FI) method is reported for the determination of thyroxine based on its enhancement of chemiluminescence (CL) from the Ru(bpy)(3)(3+)-NADH system. The calibration graph was linear over the range 2.0-10x10(-8)mol L(-1) (r(2)=0.9989) with relative standard deviations (R.S.D.) in the range 2.0-4.5% (n=4). The limit of detection (3sigma blank) was 1.0x10(-9)mol L(-1) with sample throughput of 120h(-1). The effect of some organic compounds, anions and cations were studied for l-thyroxine determination. The method was applied to pharmaceutical preparations and the results obtained were in reasonable agreement with the amount labeled. The method was statistically compared with the results obtained by RIA; no significant disagreement at 95% confidence limit was observed. A calibration graph of NADH over the range 1.3x10(-8)-1.3x10(-6)mol L(-1) was also established (r(2)=0.9992) with R.S.D. in the range1.0-3.5% (n=4). The limit of detection (3sigma) was 1.0x10(-10)mol L(-1) NADH.

Quantitative estimation of dust fall and smoke particles in Quetta Valley

Tightening of air quality standards for populated urban areas has led to increasing attention to assessment of air quality management areas, where violation of air quality standards occurs, and development of control strategies to eliminate such violation of air quality standards. The Quetta urban area is very densely built and has heavy motorized traffic. The increase of emissions mainly from traffic and industry are responsible for the increase in atmospheric pollution levels during the last years. The dust examined in the current study was collected by both deposit gauge and Petri dish methods at various sites of Quetta Valley. Smoke particles were obtained by bladder method from the exhausts of various types of motor vehicles. The concentration of lead found in the smoke ranged from 1.5×10−6 to 4.5×10−6.

Determination of total iron in fresh waters using flow injection with potassium permanganate chemiluminescence detection

A flow injection method is described for the determination of iron in fresh water based on potassium permanganate chemiluminescence detection via oxidation of formaldehyde in aqueous hydrochloric acid. Total iron concentrations are determined after reducing Fe(III) to Fe(II) using hydroxylamine hydrochloride. The detection limit (three standard deviations of blank) is 1.0 nM, with a sample throughput of 120 h−1. The calibration graph was linear over the range (2–10) × 10−7 M (r2 = 0.9985) with relative standard deviations (n = 5) in the range 1.0–2.3%. The effect of interfering cations (Ca(II), Mg(II), Zn(II), Ni(II), Co(II), Fe(III), Mn(II), Pb(II), and Cu(II)) and common anions (Cl−, SO42−, PO43−, NO3−, NO2−, I−, F−, and SO32−) was studied at their maximum admissible concentrations in fresh water. The method was applied to fresh-water samples from the Quetta Valley, and the results obtained (0.04 ± 0.001–0.11 ± 0.01 mg/L Fe(II)) were in reasonable agreement with those obtained using the spectrophotometric reference method (0.05 ± 0.01–0.12 ± 0.02 mg/L Fe(II)).

Distribution of Natural Uranium in Surface and Groundwater Resources: A Review

Keeping in view the toxicity of uranium and to reduce exposure to uranium and avoid high doses, it is essential to examine on routine bases the concentration of natural radionuclide uranium (U) in surface and groundwater resources. In this approach, the concentrations of U (total U) were summarized in worldwide surface and groundwater resources. U(+6) is the major form of U in oxic surface waters, while U(+4) is the major form in anoxic waters. An efficient way of uranium measurement in all water sources must be utilized to obtain reliable results. For this purpose a summary of available analytical techniques for U determination has also been presented. On the basis of the available data, the chemical exposures from these contaminated water sources were specified and some important epidemiological cross-sectional, ecological, and case-control studies and influence of heavy metal mining on water quality were also included. The literature review results revealed that the concentrations of natural U are higher in many parts of the world than the prescribed limit of World Health Organization. Ground and surface water in different areas of the world is contaminated with U and available data is not enough regarding water-related diseases possibly due to the lack of diagnostic facilities. Regular surveys need to be conducted in various parts of the world to obtain a clear picture of water-linked diseases.

Determination of carbaryl by flow injection with luminol chemiluminescence inhibition detection

A flow-injection procedure is described for the determination of carbaryl based on its inhibition effect on luminol-cobalt(II) chemiluminescence reaction in alkaline medium in the presence of hydrogen peroxide. The calibration data over the range 5.0 × 10−7 to 20 × 10−6 M give a correlation coefficient (r 2) of 0.9972 with relative standard deviations (RSD; n = 4) in the range of 1.0–2.1% with a limit of detection (3 × blank noise) of 2.37 × 10−7 M for carbaryl. The sample throughput was 120 h−1. The effects of some carbamates, anions, and cations were studied on luminol CL system for carbaryl determination. The proposed method has been applied to determine carbaryl in natural waters.

Determination of Thyroxine Using Tris(2,2′‐Bipyridyl)Ruthenium(III)‐NADH Enhanced Electrochemiluminescence Detection

Abstract A low cost, single channel portable flow injection electrogenerated chemiluminescence (ECL) system is reported for the determination of l‐thyroxine based on its enhancement effect on Ru(bpy)3 3+‐NADH‐ECL intensity. The calibration graph was linear over the range 5.0×10−8–1.0×10−6 mol l−1 (R 2=0.9981) with relative standard deviations (RSD, n=4) in the range 0.11–1.5%. The limit of detection (3σ blank) was 5.0×10−8 mol l−1 with a sample throughput of 60 h−1. The method was applied to pharmaceutical preparations and the results obtained (51.2±1.23–52±1.14 µg l‐thyroxine per tablet) were in good agreement with the amount labeled (50 µg l‐thyroxine per tablet, sodium salt) and RIA method (50.2±1.25 µg l‐thyroxine per tablet) as the reference method. NADH calibration graph (in the range 5.0×10−8–1.8×10−6 mol l−1, R 2=0.9989) was also established with RSD (n=4) in the range 0.25–2.1% with a limit of detection (3σ blank) 5.0×10−8 mol l−1.