A first approximation kinetic model to predict methane generation from an oil sands tailings settling basin

A small fraction of the naphtha diluent used for oil sands processing escapes with tailings and supports methane (CH(4)) biogenesis in large anaerobic settling basins such as Mildred Lake Settling Basin (MLSB) in northern Alberta, Canada. Based on the rate of naphtha metabolism in tailings incubated in laboratory microcosms, a kinetic model comprising lag phase, rate of hydrocarbon metabolism and conversion to CH(4) was developed to predict CH(4) biogenesis and flux from MLSB. Zero- and first-order kinetic models, respectively predicted generation of 5.4 and 5.1 mmol CH(4) in naphtha-amended microcosms compared to 5.3 (+/-0.2) mmol CH(4) measured in microcosms during 46 weeks of incubation. These kinetic models also predicted well the CH(4) produced by tailings amended with either naphtha-range n-alkanes or BTEX compounds at concentrations similar to those expected in MLSB. Considering 25% of MLSB's 200 million m(3) tailings volume to be methanogenic, the zero- and first-order kinetic models applied over a wide range of naphtha concentrations (0.01-1.0 wt%) predicted production of 8.9-400 million l CH(4) day(-1) from MLSB, which exceeds the estimated production of 3-43 million l CH(4) day(-1). This discrepancy may result from heterogeneity and density of the tailings, presence of nutrients in the microcosms, and/or overestimation of the readily biodegradable fraction of the naphtha in MLSB tailings.     

Effect of air-borne heavy metals on the biochemical signature of tree species in an industrial region,with an emphasis on anticipated performance index

The present study demonstrates elevated concentrations of air-borne heavy metals (Fe, 4.791; Cr, 3.142; Pb, 1.718; Cd, 0.069 μg·m^?3) in an industrial region and their subsequent accumulation in tree species grown in that area. Lagerstomia speciosa showed the highest leaf metal concentrations, whereas the lowest metal concentration was observed in Acacia moniliformis. Air accumulation factors (AAF) for heavy metals were in the sequence Cd>Cr>Pb>Fe. Plants exposed to air-borne heavy metals showed a significant (p<0.01, p<0.05) decrease in total chlorophyll and soluble sugars content, with higher synthesis of cellular antioxidants compared with ascorbic acids, proline and thiols (NP-SH). Plants with higher air-borne metal accumulation factors (AAF) generally have a high air pollution tolerance index (APTI) value. Assessment of the anticipated performance index (API) gave Alstonia scholaris as the ‘best variety’ and A. moniliformis and Shorea robusta as ‘very good’ for plantation and greenbelt development in an industrial region.     

Comparison of 1-(2-naphthyloxymethylcarbonyl) pyrrolidine,PP-20/DPJ,newly synthesized compound with the nootropic drug piracetam in normal and aluminum-induced neurotoxic state

Nootropic drugs like piracetam, oxiracetam, and nifiracetam are used as memory enhancers. They are thought to directly influence the energetic processes in the brain and produce elevated acetylcholine levels, but they lack protecting therapeutic potentials. Thus, there is a continuing effort directed towards developing a new cognition-enhancing agent, which would be more effective than the currently available drugs, and 2-Naphthyloxy derivatives (PP-20/DPJ) were consequently developed. This in vivo study was designed to compare the memory enhancing potential of PP-20/DPJ with the known nootropic agent, piracetam, in aluminum (Al)-induced neurotoxic model. Results indicated that PP-20/DPJ improved the short-term memory and cognitive behaviors similar to piracetam. Further, both the compounds were equally effective in elevating the acetylcholinesterase and Mg⁺-ATPase enzyme activity in both the brain regions after Al treatment. Thus the current study suggests, that PP-20/DPJ acts as both a cognition-enhancing agent and as a metabolic enhancer.     

Impact of coal industries on the quality of Damodar river water

Increasing demand for water in domestic, agricultural, and industrial sectors necessitates exploitation of water either in the form of groundwater or from natural resources. To safeguard the long-term sustainability of water resources and their utilization, the quality of water has to be periodically monitored and determined for various characteristics, especially when the sources are polluted, such as Damodar river. Central Institute of Mining and Fuel Research (CIMFR), Dhanbad, is carrying out research work on coal and its utilization and associated environmental concerns. The blood stream of life for the whole Jharia Coalfield is none other than the river Damodar. CIMFR's campus also depends exclusively on river Damodar for meeting its demand of drinking water. This study is a general survey toward the characteristics of Damodar river water, with special emphasis on the pollutant parameters, and evaluation of the treatment process being carried out at the institute for potability. Damodar river water is indeed affected by the disposal of the wastes without any pre-treatment by different coal-based industries established in its basin. The quantity of dissolved and suspended solids, total hardness, chemical oxygen demand, and coliform bacterial count are higher in Damodar water due to the disposal of the waste/effluents from coal-washing plants, coke ovens, cement, and other industries, but well within the permissible limit which is probably attributable to the high-carrying capacity of the river. The river is still not that much affected as it is usually apprehended, and it can be well utilized for potable and domestic purposes after simple treatment.     

Development and validation of a spectrophotometric method for soil adsorption study of malathion on three Indian soils

In view of the widespread use of pesticides in agriculture and its associated toxic effects on environment and human beings, the fate of these chemicals in soil is of major concern. The pesticide adsorption process is one of the major factors affecting its persistence and movement in the soil. With a view of studying the fate of malathion in soil, the adsorption of this insecticide was studied on three Indian soils by using batch equilibrium method. To carry out the adsorption study, a new simple, sensitive, and rapid method was developed, based on microwave-assisted alkaline hydrolysis of insecticide to the dimethyl dithiophosphate and its subsequent reaction with copper(I) perchlorate in acetonitrile. On mixing the reagents, a yellow color developed, which was stable for 120?min and was measured at 419?nm. The adsorption of malathion was studied by using Freundlich's adsorption equation and n _f values were observed less than 1 in all the soils. The leaching behavior of the insecticide was studied in terms of ground ubiquity score, which was below 1.8, classifying malathion as non-leacher pesticide, and hence it is not hazardous.     

Accumulation of heavy metals in soil and paddy crop (Oryza sativa), irrigated with water of Ramgarh Lake,Gorakhpur, UP,India

Heavy metals, a highly polluting group of constituents known to exert adverse effects, tend to accumulate in living organisms. The objective of this study was to determine the accumulation and translocation of heavy metals in soil and in paddy crop irrigated with lake water compared to soil and paddy crop irrigated with bore-well water. The quantities of heavy metals (Cd, Cr, Cu, Pb, Zn, As, Mn, and Hg) were determined in different parts of rice plants (Oryza sativa). Results revealed that the mean levels of soil Cd, Cr, Pb, Zn, As, Mn, and Hg in experimental soil and in different parts of rice plant (root, straw, and grain) were higher than the control except for Cu. The content of eight toxic metals was significantly higher in root than in aerial parts of the rice (straw and grains). Rice roots were enriched in Cd, As, Hg, and Pb from the soil, while Cr, Cu, Zn, and Mn were hardly taken by the roots. Bioaccumulation factor for Hg was significantly higher than other heavy metals. Metal transfer factors from soil to rice plants were significant for Cd, Cr, Cu, Pb, Zn, As, Mn, and Hg. The concentrations of metals in lake water were found to be within the permissible limit of Indian standard prescribed by Central Pollution Control Board (2000), except for Hg and As, which were higher than the limit of Indian standard. However, the concentrations of heavy metals in soil and rice grains were still below the maximal levels, as stipulated by Indian Prevention of Food Adulteration Act (PFA, 1954) and World Health Organization (WHO, 1993) guidelines.     

Applications of natural polysaccharide-based beads for slow release herbicide formulation

This work deals with the use of polysaccharide-based beads for controlled release of the herbicide atrazine. This article discusses the release of the herbicide atrazine from neem-alginate-clay-based beads. Formulation characteristics such as entrapment efficiency, bead size, and diffusion mechanism for release of atrazine have been evaluated.     

Amelioration of acute mercury toxicity by a novel,non-toxic lipid soluble chelator N,N′bis-(2-mercaptoethyl)isophthalamide: effect on animal survival,health, mercury excretion,and organ accumulation

The toxic effects of mercury are known to be complex with specific enzyme inhibitions and subsequent oxidative stress adding to the damaging effects. There are likely other factors involved, such as the development of impaired metal ion homeostasis and depletion of thiol- and selenium-based metabolites such as cysteine and selenium. Much of the toxicity of mercury occurs at the intracellular level via binding of Hg²⁺ to thiol groups in specific proteins. Therefore, amelioration of mercury toxicity by the use of chelation would likely be enhanced by the use of a chelator that could cross the cell membrane and the blood brain barrier. It would be most favorable if this compound was of low toxicity, had appropriate pharmacokinetics, bound and rendered mercury cation non-toxic and had antioxidant properties. Herein we report on such a chelator, N,N′-bis(2-mercaptoethyl)isophthalamide (NBMI), and, using an animal model, show that it prevented the toxic effects associated with acute exposure induced by injected mercury chloride.     

Nondestructive characterization of municipal-solid-waste-contaminated surface soil by energy-dispersive X-ray fluorescence and low-Z (atomic number) particle electron probe X-ray microanalysis

The long-term environmental impact of municipal solid waste (MSW) landfilling is still under investigation due to the lack of detailed characterization studies. A MSW landfill site, popularly known as Dhapa, in the eastern fringe of the metropolis of Kolkata, India, is the subject of present study. A vast area of Dhapa, adjoining the current core MSW dump site and evolving from the raw MSW dumping in the past, is presently used for the cultivation of vegetables. The inorganic chemical characteristics of the MSW-contaminated Dhapa surface soil (covering a 2-km stretch of the area) along with a natural composite (geogenic) soil sample (from a small countryside farm), for comparison, were investigated using two complementary nondestructive analytical techniques, energy-dispersive X-ray fluorescence (EDXRF) for bulk analysis and low-Z (atomic number) particle electron probe X-ray microanalysis (low-Z particle EPMA) for single-particle analysis. The bulk concentrations of K, Rb, and Zr remain almost unchanged in all the soil samples. The Dhapa soil is found to be polluted with heavy metals such as Cu, Zn, and Pb (highly elevated) and Ti, Cr, Mn, Fe, Ni, and Sr (moderately elevated), compared to the natural countryside soil. These high bulk concentration levels of heavy metals were compared with the Ecological Soil Screening Levels for these elements (U.S. Environment Protection Agency) to assess the potential risk on the immediate biotic environment. Low-Z particle EPMA results showed that the aluminosilicate-containing particles were the most abundant, followed by SiO2, CaCO3-containing, and carbonaceous particles in the Dhapa samples, whereas in the countryside sample only aluminosilicate-containing and SiO2 particles were observed. The mineral particles encountered in the countryside sample are solely of geogenic origin, whereas those from the Dhapa samples seem to have evolved from a mixture of raw dumped MSW, urban dust, and other contributing factors such as wind, precipitation, weather patterns, farming, and water logging, resulting in their diverse chemical compositions and the abundant observation of carbonaceous species. Particles containing C and P were more abundant in the Dhapa samples than in the countryside soil sample, suggesting that MSW-contaminated soils are more fertile. However, the levels of particles containing potentially toxic heavy metals such as Cr, Mn, Ni, Cu, Zn, and/or Pb in the Dhapa samples were significant, corroborated by their high bulk concentration levels (EDXRF), causing deep concern for the immediate environment and contamination of the food chain through food crops.