Separation and determination of trace levels of aromatic amines by HPLC

Aromatic amines were analysed by normal phase and reverse phase high performance liquid chromatography employing silica gel and octadecyl silane (ODS) columns, respectively. A number of mobile phases were used. The results obtained on silica gel column were compared with those achieved on reverse phase column. Excellent results were obtained on ODS and shoulder peaks were eliminated when a mixture of methyl alcohol and sodium perchlorate was used as mobile phase.     

Reforming the National Framework for Environmental Policies in Saudi Arabia

The current framework for national environmental policies in Saudi Arabia suffers from overlapping authority, a slow decision-making process, gaps in legislation and implementation difficulties. The paper gives a brief assessment of the existing framework including: political culture; environmental decision making process; environmental institutions; and environmental awareness. This is followed by a proposal for reforming the current framework.The proposalcovers four main sectors: political culture and the public role; environmental decision making; environmental policies and laws; and institutional structure.     

Application of association rules in Iranian Railways (RAI) accident data analysis

The demand to travel by rail is ever increasing because it benefits both passengers and freight; therefore it is of utmost importance for railway administrators to carry passengers and freight safely to their destinations. Undergoing safety procedures and developing safety systems require awareness of what is causing unsafe conditions. This can be accomplished by learning from the past. This research has been performed to analyze the data from past accidents of the Iranian Railway (RAI) by applying association rules data mining techniques in order to discover and reveal unknown relationships and patterns among the data. By the application of CRISP-DM as the data mining methodology and utilizing Clementine 12.0 as the software tool, the mentioned objectives of this paper were fulfilled. For this research some 6500 accident records were selected from the accidents database from 1996 to 2005. The ultimate relationships and patterns extracted can been utilized to develop regulations and rules. This research considers accident conditions and relationships discovered among the most common accident factors (human error, wagon and track) with other fields of the database in order to prevent them from occurring in the future.     

Visible-light-driven photocatalytic dual-layer hollow fibre membrane ameliorates the changes of bisphenol A exposure in gastrointestinal tract

Environmental Science and Pollution Research - Various treatments of choice are available to overcome contamination of bisphenol A (BPA) in the environment including membrane technologies; however,...     

Improvements in the stability of biodiesel fuels: recent progress and challenges

Environmental Science and Pollution Research - Fewer fossil fuel deposits, price volatility, and environmental concerns have intensified biofuel-based studies. Saccharification, gasification, and...     

A quantitative investigation of methane gas and solid waste management in mountainous Srinagar city-A case study

Journal of Material Cycles and Waste Management - Methane has tremendous potential for energy production, and enormous amounts of energy can be produced using suitable technology. To address this...     

Release,deposition and elimination of radiocesium (137Cs) in the terrestrial environment

Radionuclide contamination in terrestrial ecosystems has reached a dangerous level. The major artificial radionuclide present in the environment is ¹³⁷Cs, which is released as a result of weapon production related to atomic projects, accidental explosions of nuclear power plants and other sources, such as reactors, evaporation ponds, liquid storage tanks, and burial grounds. The release of potentially hazardous radionuclides (radiocesium) in recent years has provided the opportunity to conduct multidisciplinary studies on their fate and transport. Radiocesium’s high fission yield and ease of detection made it a prime candidate for early radio-ecological investigations. The facility setting provides a diverse background for the improved understanding of various factors that contribute toward the fate and transfer of radionuclides in the terrestrial ecosystem. In this review, we summarize the significant environmental radiocesium transfer factors to determine the damaging effects of radiocesium on terrestrial ecosystem. It has been found that ¹³⁷Cs can trace the transport of other radionuclides that have a high affinity for binding to soil particles (silts and clays). Possible remedial methods are also discussed for contaminated terrestrial systems. This review will serve as a guideline for future studies of the fate and transport of ¹³⁷Cs in terrestrial environments in the wake of the Fukushima Nuclear Power Plant disaster in 2011.     

High photocatalytic decomposition of the air pollutant formaldehyde using nano-ZnO on bone char

Air pollution is a major issue leading to many serious illnesses. Exposure to formaldehyde may occur by breathing contaminated indoor air, tobacco smoke, or ambient urban air. Exposure to formaldehyde has been associated with lung and nasopharyngeal cancer. Therefore, there is a need for methods to degrade formaldehyde. Here, we studied the photocatalytic decomposition of gaseous formaldehyde over nanosized ZnO particles on bone char. The conditions were UV/bone char, UV/ZnO nanoparticles, and UV/ZnO-bone char in continuous flow mode. We investigated the effects of humidity, initial formaldehyde concentration, and residence time on decomposition of formaldehyde. Agglomeration of ZnO particles in the bone char pores was characterized by Brunauer, Emmett, and Teller surface area, and scanning electron micrograph. Results show that maximum decomposition efficiency of formaldehyde was 73 %. The optimal relative humidity was by 35 %. Findings also indicated that immobilization of ZnO nanoparticles on bone char has a synergetic action on photocatalytic degradation. This is explained by the strong adsorption of formaldehyde molecules on bone char, resulting in higher diffusion to the catalytic ZnO and thus a higher rate of photocatalysis.     

Inhibitory effect of arachidonic acid on venom acetylcholinesterase

The venom of krait (Bungarus sindanus), an Elapidae snake, contains high level of acetylcholinesterase (AChE) activity. The effect of arachidonic acid on krait (Bungarus sindanus) venom AChE (acetylcholine hydrolase, EC 3.1.1.7) was studied using kinetic methods. This study evaluated for the first time whether arachidonic acid acts as potential AChE inhibitor of krait venom. Kinetic studies, using Line-Weaver Burk and Dixon plots, indicated that the inhibition produced by arachidonic acid was non-competitive, i.e., both k_m and V _max fell with increase in the concentration of arachidonic acid. The concentration of arachidonic acid required to inhibit 50% of enzymatic activity was found to be 1.9?µM while the inhibitory constant (K_i ) was 1.4?µM. The present results suggest that essential fatty acid (arachidonic acid) may also be used as an inhibitor of snake venom AChE.     

Toxicity of metals to tadpoles of the common Sunda toad,Duttaphrynus melanostictus

Tadpoles of the common freshwater Sunda toad, Duttaphrynus melanostictus (Amphibia, Bufonidae), were exposed for a 4-day period under laboratory conditions to copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminum (Al), and manganese (Mn) at various concentrations. Mortality was assessed and median times of death (LT₅₀) and lethal concentrations (LC₅₀) were calculated. LT₅₀ and LC₅₀ increased with the decrease in mean exposure times and concentrations for all metals. LC₅₀ (96?h) for Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.03, 0.3, 4.2, 1.5, 8.8, 0.4, 1.9, and 39?mg?L^?1, respectively. Cu was the most toxic to D. melanostictus, followed by Cd, Fe, Al, Pb, Zn, Ni, and Mn (Cu?>?Cd?>?Fe?>?Al?>?Pb?>?Zn?>?Ni?>?Mn). Duttaphrynus melanostictus is similarly sensitive to these metals as other amphibian tadpoles.