Degradation of 14C-glyphosate and aminomethylphosphonic acid (AMPA) in three agricultural soils

Glyphosate (N-phosphonomethyl glycine) is the most used herbicide worldwide. The degradation of 14C-labeled glyphosate was studied under controlled laboratory conditions in three di erent agricultural soils: a silt clay loam, a clay loam and a sandy loam soil. The kinetic and intensity of glyphosate degradation varied considerably over time within the same soil and among di erent types of soil. Our results demonstrated that the mineralization rate of glyphosate was high at the beginning of incubation and then decreased with time until the end of the experiment. The same kinetic was observed for the water extractable residues. The degradation of glyphosate was rapid in the soil with low adsorption capacity (clay loam soil) with a short half-life of 4 days. However, the persistence of glyphosate in high adsorption capacity soils increased, with half-live of 19 days for silt clay loam soil and 14.5 days for sandy loam soil. HPLC analyses showed that the main metabolite of glyphosate, aminomethylphosphonic acid (AMPA) was detected after three days of incubation in the extracts of all three soils. Our results suggested that the possibility of contamination of groundwater by glyphosate was high on a long-term period in soils with high adsorption capacity and low degrading activities and/or acid similar to sandy loam soil. This risk might be faster but less sustainable in soil with low adsorption capacity and high degrading activity like the clay loam soil. However, the release of non-extractable residues may increase the risk of contamination of groundwater regardless of the type of soil.     

Isolation of Cr(Ⅵ) reducing bacteria from industrial effluents and their potential use in bioremediation of chromium containing wastewater

The present study is aimed at assessing the ability of Bacillus sp.JDM-2-1 and Staphylococcus capitis to reduce hexavalent chromium into its trivalent form.Bacillus sp.JDM-2-1 could tolerate Cr(Ⅵ) (4800 μg/mL) and S.capitis could tolerate Cr(Ⅵ) (2800 μg/mL).Both organisms were able to resist Cd2+ (50 μg/mL),Cu2+ (200 μg/mL),Pb2+ (800 μg/mL),Hg2+ (50 μg/mL) and Ni2+ (4000 μg/mL).S.capitis resisted Zn2+ at 700 μg/mL while Bacillus sp.JDM-2-1 only showed resistance up to 50 μg/mL.Bacillus sp.JDM-2-1 and S.capitis showed optimum growth at pH 6 and 7,respectively,while both bacteria showed optimum growth at 37℃.Bacillus sp.JDM-2-1 and S.capitis could reduce 85% and 81% of hexavalent chromium from the medium after 96 h and were also capable of reducing hexavalent chromium 86% and 89%,respectively,from the industrial effluents after 144 h.Cell free extracts of Bacillus sp.JDM-2-1 and S.capitis showed reduction of 83% and 70% at concentration of 10 μg Cr(Ⅵ)/mL,respectively.The presence of an induced protein having molecular weight around 25 kDa in the presence of chromium points out a possible role of this protein in chromium reduction.The bacterial isolates can be exploited for bioremediation of hexavalent chromium containing wastes,since they seem to have the potential to reduce the toxic hexavalent form to its nontoxic trivalent form.     

Tualang honey supplementation improves oxidative stress status among chronic smokers

Free radicals induced by cigarette smoking have been linked to an increase in oxidative stress resulting in smoking-related cardiovascular diseases. However, the possible effect of honey that has antioxidant property in improving oxidative stress status among smokers has not yet been reported. Hence, this study was to determine the effects of 12-week Tualang honey supplementation on F₂-isoprostanes, superoxide dismutase, glutathione peroxidase, catalase, and total antioxidant status among chronic smokers. A total of 32 non-smokers and 64 chronic smokers were recruited from Quit Smoking Clinic and Health Campus, Universiti Sains, Malaysia. Smokers were randomized into two groups (n = 32/group) namely smokers without supplementation and smokers with honey supplementation (20 g/day) for 12 weeks. Blood was obtained from non-smokers and smokers at pre-intervention and from smokers at post-intervention. During pre-intervention, the levels/activity of F₂-isoprostanes, total antioxidant status, and catalase were significantly higher while superoxide dismutase and glutathione peroxidase were lower in smokers than non-smokers. During post-intervention, in supplemented smokers, there were significant decrease in F₂-isoprostanes and increase in total antioxidant status, glutathione peroxidase and catalase levels/activities compared with pre-intervention. This study indicates that honey supplementation improves oxidative stress status suggesting a beneficial role of honey in reducing the risk of cardiovascular diseases.     

Determinants of privatized solid waste management service provision in Lagos

The growing popularity of privatized solid waste management service in least developed countries warrants an exploration of factors that are likely to impact on its sustainability. This study takes integrated solid waste management approach by analyzing relevant issues on both market sides. We use a three step theme development sequence to analyze the data obtained on service providers through library research, observations and interviews. This was followed by an opinion survey on the demand side to elicit households’ support for service improvement. Findings show that source-separation issues, government enforcement, market segmentation, financial issues and waste disposal issues are key factors influencing improved service provision. Meanwhile, on the demand side, we found that households are willing to support proposed regulatory improvement in service provision. Thus, we suggest industrial stakeholders to consider the aforementioned supply side issues in designing future service improvements that will take advantage of existing demand side feasibility.     

Lead Content of Petrol and Diesel and its Assessment in an Urban Environment

Pakistan is one of the few countries in Asia thatcontinues to use only leaded-petrol as vehicular fuel. Theconcentration of Pb in its petrol reported in 1991 was thehighest (1.5 – 2.0 g Pb L^-1) of all produced by the various Asiancountries and far exceeded the WHOs guideline of 0.15 g Pb L^-1. We have undertaken a study to trace and quantify this toxicelement in the environs of Karachi, Pakistans major metropolis,having more than 30% of the nations total number of vehicles.In this article we report the Pb contents of petrol and dieselcurrently manufactured and marketed in the city. Samples of`Regular petrol collected in 1999 was found to contain 0.363 gPb L^-1 (range: 0.335 – 0.390 g Pb L^-1), a factor of 5 lower than thatmarketed prior to 1991. Its concentration in diesel fuel was muchlower (0.017 g Pb L^-1). Based on the available statistical data onthe type and volume of vehicular traffic, we assessed that thecurrent lead emission from vehicular traffic into the atmosphereis 391 metric tons a year, which is a factor of 2.7 lower thanthat estimated for 1989.     

Seasonal Variation in Bacterial Flora of the Wastewater and Soil in the Vicinity of Industrial Area

Environmental pollution is one of the major problems being facedtoday due to the advent of extensive industrialization. Heavy metals are the most important contaminants in wastewater that are present in abundance and are toxic. Heavy metal contentsof sewage in the industrial estate of Aligarh (U.P.) have beendetermined by atomic absorption spectrophotometry. The analysisof samples collected from six different locations revealedsignificantly high levels of Fe, Zn, Cu, Cr and Ni. Certainbacteriological (Total bacterial count, Total coliform, Fecal coliform, and Fecal Streptococci) parameters of domestic and industrial sewage as well as soils were monitored from March1990 to January 1993. Total bacterial count, total coliform,fecal coliform and fecal streptococci were found to be lowestin all the samples of industrial wastewater compared to thosein domestic sewage and soil systems. The soil however, contained highest total culturable bacterial population. In view of the common practice of the application of sewage to agricultural land in the neighbouring area, the discharge ofindustrial wastewater without proper treatment into public sewers should be strictly prohibited.     

Photocatalytic degradation of Chicago Sky Blue 6B and Benzopurpurin 4B using titanium dioxide thin film

Aqueous solutions of azo dyes undergo degradation to form harmless intermediates and colorless products following irradiation by visible light in the presence of titanium dioxide thin films. The dyes that were studied in this work are： Chicago Sky Blue 6B and Benzopurpurin 4B. Results obtained indicated that complete mineralization of the dyes took place under the experimental conditions. There was an increase in conductivity after the complete mineralization experiments possibly indicating the formation of ions such as NO3^- and SO4^2-. Chemical oxygen demand（COD） measurements show a decrease in organic matter for both dyes following complete degradation. The effect of how changing experimental conditions such as pH, temperature and starting concentrations of dyes affected the rate of dye degradation was measured. There was an increase in the rate of disappearance of the dye color at lower pH. High concentrations of dye solutions reauired Iona dearadation time.     

Polybrominated diphenyl ethers (PBDEs) in soils along a rural-urban-rural transect: sources, concentration gradients, and profiles

This study reports concentrations of PBDEs in surface soil samples collected along a 140 km transect across Kuwait to assess the role of urban centers as sources of persistent organic pollutants to the surrounding environment. The ΣPBDE concentrations varied by a factor of ∼250 and ranged from 289 to 80,078 pg g⁻¹ d.w. The concentrations of PBDEs in Kuwait City were significantly higher (p < 0.01) than those collected from sites outside the city supporting the hypothesis that urban centers are sources of PBDEs. The congener profiles were dominated by BDE-209, accounting for 93% of the PBDEs in the soil samples. The concentrations of all congeners (except BDE-209) were highly correlated with percent organic carbon (%OC) (p > 0.05) when the data from Kuwait City was omitted from the analysis. These findings suggest that soil concentrations outside the urban centers were close to equilibrium with the atmosphere.     

Expert System for Terrestrial Vegetation Distribution, Potential Impact and Mitigation Abatement Measures

The tropical rainforest of Malaysia holds one of the richest flora in the world. The favourable climate has produced flora of amazing richness and variety. Terrestrial vegetation of tropical rainforests is an important feature of the environment. Plants play a major role in the environment and conservation of a particular environment depends fundamentally on the maintenance of existing plants and their communities and hierarchies. Interference in the balance of the ecosystem may produce radical changes that lead to progressive deviations from the original situation. Therefore, the application of a computer technology in the form of an expert system (ES) will be able to help in the analysis and management of the EIA information. The ES is named VEGEVIC. Application of the system will lead to greater consistency in the application of EIA through implementation of a standard approach.     

Combustion in porous media and its applications – A comprehensive survey

The rapid advances in technology and improved living standard of the society necessitate abundant use of fossil fuels which poses two major challenges to any nation. One is fast depletion of fossil fuel resources; the other is environmental pollution. The porous medium combustion (PMC) has proved to be one of the technically and economically feasible options to tackle the aforesaid problems to a remarkable extent. PMC has interesting advantages compared with free flame combustion due to the higher burning rates, the increased power dynamic range, the extension of the lean flammability limits, and the low emissions of pollutants. This article provides a comprehensive picture of the global scenario of research and developments in PMC and its applications that enable a researcher to decide the direction of further investigation. The works published so far in this area are reviewed, classified according to their objectives and presented in an organized manner with general conclusions. A separate section is devoted for the numerical modeling of PMC.