Sediments deposition due to soil erosion in the watershed region of Mangla Dam

Soil erosion is the most important reason of sedimentation load of water reservoirs in the world. In Pakistan, Mangla dam is one of the most important water reservoirs used for the production of electricity and for the supply of water for irrigation purposes. However, the capacity of Mangla dam reservoir has reduced by more than 20% since its construction. This study highlights the impact of rainfall on soil erosion and consequently on sedimentation deposition in Mangla dam reservoir. Sedimentation, annual rainfall, and normal rainfall data of 39 years were used in this study. Shuttle Radar Topographic Mission data were used to calculate the total drainage area of the Mangla watershed region. The sedimentation data of Mangla reservoir from 1967 to 2005 were retrieved from Water and Power Development Authority in Pakistan. The meteorological observatories in the Mangla watershed region are identified. Annual rainfall data from 1967 to 2005 for the meteorological observatories in the Mangla watershed regions were retrieved from Pakistan Meteorological Department (PMD). In addition, normal rainfall data for the years 1949 to 1978 and for the years 1979 to 2008 were also retrieved from PMD. The impact of annual rainfall is observed on sedimentation load in Mangla dam. The correlation coefficient between annual rainfall and sedimentation load is 0.94. This study shows that with an increase in rainfall, the soil erosion of the area increases which subsequently is responsible for the increase in the rate of sedimentation load in Mangla dam. This study further demonstrates that better soil management can reduce the sedimentation load in the Mangla reservoir.     

Bioavailability and toxicity to rats of bound residues of 14C-pirimiphos-methyl in stored wheat.

Wheat grains were treated with 14C-pirimiphos-methyl to generate bound residues for testing their bioavailability to rats. Bound residues accounted for 25% of the applied dose (50 ppm) at the end of one year. When the grain bound residues were fed to rats for 48 hours the animals eliminated 30 and 40% of the administered dose in urine and feces respectively, after 5 days. Radioactivity in some selected organs and blood accounted for 37% of the administered dose after 2 days, which gradually declined to 1% after 5 days. These data indicate that wheat-bound pirimiphos-methyl residues are moderately bioavailable to rats. In a 90-day feeding study, inhibition of plasma cholinesterase and brain acetylcholinesterase strongly suggest that the bound residues possess a toxicological potential.     

Remediation of 4-nonylphenol in aqueous solution by using free radicals generated by the oxidative reactions

Introduction

This study relates to use of zerovalent iron to generate hydroxyl free radicals and undergo subsequent oxidation to destroy 4-nonylphenol (NP) by mild process in aqueous solution and activation of oxygen gas (O₂) at room temperature. This technology is based on a novel oxidative mechanism mediated by zerovalent iron rather than commonly used reduction mechanism.

Materials and methods

A laboratory scale device consisting of a 250?ml pyrex serum vials fixed to a Vortex agitator was used. Different amounts of zerovalent iron powder (ZVI; 1, 10, and 30?g/l) at pH?4 and room temperature with bubbling of oxygen gas were investigated.

Results and conclusion

Experiments showed an observed degradation rate k _(obs) directly proportional to the amount of iron. 4-Nonylphenol degradation reactions demonstrated first-order kinetics with a half-life of about 10.5?±?0.5 and 3.5?±?0.2?min when experiments were conducted at [ZVI]?=?1 and 30?g/l respectively. Three analytical techniques were employed to monitor 4-nonylphenol degradation and mineralization: (1) spectrofluorimetry; (2) high-performance liquid chromatography; (3) total organic carbon meter (TOC meter). Results showed a complete disappearance of 4-nonylphenol after 20?min of contact with ZVI. The intermediate by-products of the reaction were not identified but the disappearance of NP was monitored by the three above-mentioned techniques.     

Sub-chronic effect of neem based pesticide (Vepacide) on acetylcholinesterase and ATPases in rat.

Acetylcholinesterases (AChE), Na(+)-K+, Mg2+ and Ca(2+)-ATPases were monitored in rat brain when treated orally with 80, 160 and 320 mg/kg of Vepacide, an active ingredient from neem seed oil, daily for 90 days. Brain AChE, Na(+)-K+ and Ca(2+)-ATPases were inhibited whereas Mg(2+)-ATPase levels were enhanced in both the sexes after 45 and 90 days of treatment. The relative sensitivities of these ATPases to Vepacide indicated that Ca(2+)-ATPase being more sensitive than Na(+)-K(+)-ATPase in both the sexes. The magnitude of Ca(2+)-ATPase inhibited by this compound was higher than that of brain AChE. It appears to be sexual dimorphism in the alterations of brain AChE, Na(+)-K+ and Mg(2+)-ATPases by Vepacide with females being significant when compared with males. After 28 days of post treatment the alterations observed were approached to those of controls both in male and female rats showing reversal of the toxicity. These results indicated that the ATPases were potently inhibited by Vepacide and seemed to be its precise target among the enzyme studied. This can be used as biochemical marker of exposure to this neem derived product.     

Recent Progress in Silane Coupling Agent with Its Emerging Applications

Journal of Polymers and the Environment - This paper presents the effects of silane coupling agent, which includes interfacial adhesive strength, water treatment, polymer composites and coatings...     

Experimental and Monte Carlo simulation studies of open cylindrical radon monitoring device using CR-39 detector

There are several methods of measuring radon concentrations but nuclear track detector cylindrical dosimeters are widely employed. In this investigation, the consequence of effective volumes of the dosimeters on the registration of alpha tracks in a CR-39 detector was studied. In a series of experiments an optimum radius for a CR-39-based open cylindrical radon dosimeter was found to be about 3 cm. Monte Carlo simulation techniques have been employed to verify the experimental results. In this context, a computer code Monte Carlo simulation dosimetry (MOCSID) was developed. Monte Carlo simulation experiments gave the optimum radius of the dosimeters as 3.0 cm. The experimental results are in good agreement with those obtained by Monte Carlo design calculations. In addition to this, plate-out effects of radon progeny were also studied. It was observed that the contribution of radon progeny (218Po and 214Po) plated-out on the wall of the dosimeters increases with an increase of dosimeter radii and then decrease to 0 at a radius of about 3 cm if a point detector has been installed at the center of the dosimeter base. In the code MOCSID different types of random number generators were employed. The results of this research are very useful for designing an optimum size of radon dosimeters.     

Noise pollution in textile,printing and publishing industries in Saudi Arabia

A study of 20 factories belonging to textile, printing, publishing and paper products industries in Jeddah was conducted.Data on Leq, Maximum and Minimum SPL at different octave bands, as well as dBA, were collected. It has been found that textile,publishing and paper products industries are the most noisy industries. The paper is concluded with suitable recommendationfor noise control and worker protection.     

Stimulating environmental performance via green human resource management,green transformational leadership,and green innovation: a mediation-moderation model

Environmental Science and Pollution Research - This study aims to evaluate the environmental performance of small and medium-sized enterprises (SMEs) through green human resource...     

Pb-induced changes in roots of two cultivated rice cultivars grown in lead-contaminated soil mediated by smoke

Environmental Science and Pollution Research - Nowadays, public concerns regarding deleterious effect of lead (Pb) is on rise due to its abundance and toxic effect on plants and other living...