CIELAB color variables as indicators of compost stability

The composting process of different organic wastes both in laboratory and on a large-scale was characterized using CIELAB color variables to evaluate compost stability for the better application in agriculture. The time courses of the CIELAB variables of composting materials were determined directly from the bottom of a glass petri dish filled with dried and ground samples using a Minolta Color Reader (CR-13) calibrated with clean empty petri dishes placed on a white tile. To compare the proposed method with conventional methods, the same materials were also evaluated using commonly used compost stability evaluation indices. Most of the CIELAB variables of a compost made from a mixture of green tea waste and rice bran reached a plateau after 84 days of composting and showed strong relationships with the commonly used compost stability evaluation indices. The time needed for CIELAB variables, especially the L*and b* values, to stabilize at large-scale composting plants of cattle litter, farmyard manure, kitchen garbage and bark compost, were more or less similar to the times of maturation evaluated by the respective compost producers. The CIELAB color variable offers a new, simple, rapid and inexpensive means of evaluating compost stability and its quality prior to agricultural use.     

Black carbon aerosols in urban air in South Asia

We report data from a yearlong (2006–2007) study of black carbon concentrations ([BC]) measured at 5-min intervals with an Aethalometer in Karachi, Pakistan. Daily mean [BC] varied from about 1 to 15 μg m^?3. However, short-term spikes exceeding 40 μg m^?3 were common, occurring primarily during the morning and evening rush-hour periods. The [BC] values were highest during November through February, ～10 μg m^?3, and lowest during June through September, ～2 μg m^?3. Diurnal, seasonal, and day-of-the-week trends are discussed. It is demonstrated that these trends are strongly affected by meteorological patterns. A simple expression is applied to the concentration profiles to separate the effects of meteorological conditions and elucidate the underlying emissions patterns. Daily emissions varied from 14,000 to 22,000 kg of BC per day. When integrated over the year emissions for Karachi Proper were estimated at 6.7 kilometric tons per year and emissions for greater Karachi were 17.5 kilometric tons per year. Folding in the populations of each area yields BC emissions of 0.74 and 1.1 kg per person per year, respectively. Applying the model to previously collected data at Lahore, Pakistan yields emissions during November–January that are around a factor of two higher than those in Karachi, but because the BC measurements in Lahore covered only three months, no estimates of annual emissions were attempted. Given the large populations of these cities the local health impact from PM alone is expected to be severe but because of the high [BC] emissions the impact on the global climate may be equally significant.     

Influence of sub-lethal crude oil concentration on growth,water relations and photosynthetic capacity of maize (Zea mays L.) plants

Environmental Science and Pollution Research - Maize tolerance potential to oil pollution was assessed by growing Zea mays in soil contaminated with varying levels of crude oil (0, 2.5 and...     

Comparative efficacy of mitigation techniques for the detoxification of Prunus persica (L.) from selected pesticide residues

Environmental Science and Pollution Research - Fruits are the valuable and important components of human diet. Among them, Prunus persica is a rich source of different minerals and dietary fibers....     

Bacterial-mediated synthesis of silver nanoparticles and their significant effect against pathogens

Environmental Science and Pollution Research - Silver nanoparticles are potent antimicrobials and could be used as a promising alternative of conventional antibiotics. The aim of this study was to...     

Brain glutathione redox system significance for the control of silica-coated magnetite nanoparticles with or without mercury co-exposures mediated oxidative stress in European eel (Anguilla anguilla L.)

This in vitro study investigates the impact of silica-coated magnetite particles (Fe₃O₄@SiO₂/SiDTC, hereafter called IONP; 2.5 mg L^?1) and its interference with co-exposure to persistent contaminant (mercury, Hg; 50 μg L^?1) during 0, 2, 4, 8, 16, 24, 48, and 72 h on European eel (Anguilla anguilla) brain and evaluates the significance of the glutathione (GSH) redox system in this context. The extent of damage (membrane lipid peroxidation, measured as thiobarbituric acid reactive substances, TBARS; protein oxidation, measured as reactive carbonyls, RCs) decreased with increasing period of exposure to IONP or IONP + Hg which was accompanied with differential responses of glutathione redox system major components (glutathione reductase, GR; glutathione peroxidase, GPX; total GSH, TGSH). The occurrence of antagonism between IONP and Hg impacts was evident at late hour (72 h), where significantly decreased TBARS and RC levels and GR and glutathione sulfo-transferase (GST) activity imply the positive effect of IONP + Hg concomitant exposure against Hg-accrued negative impacts [vs. early (2 h) hour of exposure]. A period of exposure-dependent IONP alone and IONP + Hg joint exposure-accrued impact was perceptible. Additionally, increased susceptibility of the GSH redox system to increased period of exposure to Hg was depicted, where insufficiency of elevated GR for the maintenance of TGSH required for membrane lipid and cellular protein protection was displayed. Overall, a fine-tuning among brain glutathione redox system components was revealed controlling IONP + Hg interactive impacts successfully.     

Control of combustion-generated nitrogen oxides by selective non-catalytic reduction

Controlling nitrogen oxides (NO(x)) emissions is becoming a daunting technical challenge as increasingly strict emission limits are being imposed. The stringent regulations have prompted the innovation and characterization of NO(x) control technologies suitable for various applications. This paper presents a review on NO(x) removal techniques with particular reference to selective non-catalytic reduction (SNCR) technology. This includes initially how SNCR emerged as a technology along with a comparison with other relevant technologies. A review of various features related to selective non-catalytic gas phase injection of ammonia and ammonium salts (as reducing agent) is presented. The use of urea solution as a reducing agent and its performance in laboratory and pilot scale tests as well as large-scale applications is also discussed. Use of cyanuric acid as a potential reducing agent is also presented. The underlying reaction mechanisms have been reviewed for ammonia, urea and cyanuric acid for the explanation of various observations. Computational fluid dynamics (CFD) modeling as applied to SNCR is also presented. Subsequently the use of SNCR coupled with other in-combustion and post-combustion NO(x) control techniques is elaborated. Additionally, a two-stage NO(x) removal strategy to control un-reacted ammonia slip and to improve overall efficiency is discussed. At the end a summary is given which highlights various areas needing further research.     

Statistical apportionment and risk assessment of selected metals in sediments from Rawal Lake (Pakistan)

The present study was carried out in order to evaluate the statistical apportionment and risk assessment of selected metals (Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Pb, Sr, and Zn) in freshly deposited sediments in Rawal Lake, Pakistan. Composite sediment samples were collected, oven-dried, grounded, homogenized, and processed to assess the water-soluble and acid extractable concentrations of the metals in the water extract and acid extract of the sediments using flame atomic absorption spectrophotometer. Statistical methods were used to identify the possible sources of the metals. Sediment quality guidelines and potential acute toxicity were used to evaluate the ecotoxicological sense of selected metals. Non-carcinogenic health risk assessment was also carried out to determine the potential adverse health risks to the inhabitants. Relatively higher concentration was noted for Ca, Fe, Mg, Na, K, Mn, and Sr in the sediment samples. Principal component analysis and cluster analysis revealed anthropogenic contributions of Cd, Pb, Cr, Mn, Fe, and Li in the sediments. Enrichment factors of the metals in sediments showed severe to moderate enrichment of Cd, Pb, Ca, Fe, Li, Mn, and Sr. Geoaccumulation indices and contamination factors evidenced significant contamination by Cd and Pb, although, on the whole, low degree of contamination was noted. The levels of some metals exceeded the sediment quality guidelines, which revealed frequently adverse biological effects to the dwelling biota in the aquatic ecosystem. The sediments were found to be significantly contaminated by Cd, Pb, Cr, Mn, Fe, and Li.     

Studies on the effects of some organic pollutants on the heavy metal transport in an Indian soil

The translocation of some heavy metals, such as Hg, Cd, Cu, Co, Ni and Zn, as affected by organic pollutants, i.e. methanol, ethanol, propanol, formaldehyde, acetaldehyde, benzaldehyde, acetone, ethyl methyl ketone and cyclo-hexanone, was studied in an Indian red soil using soil thin layer chromatography. It was observed that an increase in the concentration of organic compounds in developer enhances the heavy metal mobility, except in the case of Cu and Hg which show a decreasing trend. The results are discussed in relation to the physico-chemical characteristics of the soil and adsorption/desorption phenomena.     

Genotoxicity of ferric oxide nanoparticles in Raphanus sativus: Deciphering the role of signaling factors, oxidative stress and cell death

We have studied the genotoxic and apoptotic potential of ferric oxide nanoparticles(Fe_2O_3-NPs) in Raphanus sativus(radish).Fe_2O_3-NPs retarded the root length and seed germination in radish.Ultrathin sections of treated roots showed subcellular localization of Fe_2O_3-NPs,along with the appearance of damaged mitochondria and excessive vacuolization.Flow cytometric analysis of Fe_2O_3-NPs(1.0 mg/m L) treated groups exhibited 219.5%,161%,120.4% and 161.4% increase in intracellular reactive oxygen species(ROS),mitochondrial membrane potential(ΔΨm),nitric oxide(NO) and Ca2+influx in radish protoplasts.A concentration dependent increase in the antioxidative enzymes glutathione(GSH),catalase(CAT),superoxide dismutase(SOD) and lipid peroxidation(LPO) has been recorded.Comet assay showed a concentration dependent increase in deoxyribonucleic acid(DNA) strand breaks in Fe_2O_3-NPs treated groups.Cell cycle analysis revealed 88.4% of cells in sub-G1 apoptotic phase,suggesting cell death in Fe_2O_3-NPs(2.0 mg/m L) treated group.Taking together,the genotoxicity induced by Fe_2O_3-NPs highlights the importance of environmental risk associated with improper disposal of nanoparticles(NPs) and radish can serve as a good indicator for measuring the phytotoxicity of NPs grown in NP-polluted environment.