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951.
Manasi Mukherjee Vettath Raghavan Suresh Ranjan Kumar Manna 《Environmental monitoring and assessment》2018,190(11):689
Microplankton population of Asia’s largest coastal lagoon Chilika was studied for five major groups, bacillariophyceae, cyanophyceae, chlorophyceae, dinophyceae, rotifera, and tintinninae. The study reported presence of 233 species of microplankton whose average annual abundance was 1631 cells/l. The physicochemical parameters contributing to the spatio-temporal fluctuations in microplankton diversity, abundance, and community structure were identified as salinity, pH, DO, nitrate, and silicate. Salinity, transparency, depth, and silicate most explained the abundance of bacillariophyceae; nitrate, pH, and DO influenced cyanophyceae; salinity, transparency, and chlorophyll concentration influenced chlorophyceae; salinity, depth, and water temperature influenced dinophyceae; salinity, free CO2, and nitrate-influenced rotifers, whereas salinity, pH, DO, and depth influenced tintinnids. Biotic-abiotic relationships revealed particular preference of environmental conditions at species level in groups like bacillariophyceae, cyanophyceae, and dinophyceae. Although the lagoon is shallow, bacillariophyceae-environment interaction showed depth can be a critical factor for species like Aulocoseira sp., Amphipleura sp., and Rhophalodia sp. Species of dinoflagellates like Dinophysis caudata, Noctiluca scintillans, and Protoperidinium proliferated in lower level of silicate. Unlike other cyanophyceae species Streptococcus sp., Chroococcus sp., Diplococcus sp., Aphanocapsa sp., and Gloeocapsa sp. were negatively influenced by nitrate concentration. The study provides better scope for ecological management of the lagoon with respect to conserving biodiversity and hydrological quality of the ecosystem. 相似文献
952.
Atul Kumar Jatinder Paul Singh Gill Jasbir Singh Bedi Amit Kumar 《Environmental science and pollution research international》2018,25(34):34005-34016
Honey has multifaceted beneficial properties, but polluted environment and unapproved apicultural practices have led to its contamination. In this study, QuEChERS method followed by chromatographic analysis by GC-μECD/FTD and GC-MS was validated and used for determination of 24 pesticides in 100 raw honey samples from various floral origins of Northern India. Matrix-matched calibrations showed that the method was selective and linear (r2?>?0.99) with detection limit <?9.1 ng g?1 for all the studied pesticides except for monocrotophos (21.3 ng g?1). The average recoveries at different fortification levels ranged from 86.0 to 107.7% with relative standard deviation <?20%. Pesticide residues were detected in 19.0% samples, and most prevalent compounds detected were dichlorvos in 6.0% samples followed by monocrotophos (5.0%), profenofos (5.0%), permethrin (4.0%), ethion (3.0%), and lindane (3.0%) with concentrations ranging from 58.8 to 225.5, from 96.0 to 430.1, from 14.6 to 43.2, from 27.8 to 39.6, from 25.6 to 28.0, and from 19.6 to 99.2 ng g?1, respectively. Honey samples originating from cotton, sunflower, and mustard crops (33.3%) that tested positive for pesticide residues were found to be significantly higher (p?<?0.05) than the honey originating from natural and fruity vegetation (13.5%). Therefore, considering the contamination of environmental compartments due to extensive application of pesticides in the study area and their potential for subsequent transfer to honey by the expeditious bees, the results of present study proclaim that honey may be used as an indicator of environmental pollution. Further, estimated daily intakes of all contaminants were found to be at levels well below their acceptable daily intakes suggesting that consumption of honeys at current levels does not pose deleterious effects on human health. However, precautionary measures should always be taken considering the customary honey feeding in infants and cumulative effect of these chemicals in the foreseeable future. 相似文献
953.
Dhanya Vishnu Gerard Neeraj Ramachandran Swaroopini Ravi Shobana Vaidyanathan Vinoth Kumar Hubert Cabana 《Environmental science and pollution research international》2017,24(22):17993-18009
In this study, a tailor-made biocatalyst consisting of a co-immobilized lignolytic enzyme cascade on multi-functionalized magnetic silica microspheres (MSMS) was developed. Physical adsorption was the most promising strategy for the synthesis of individual immobilized laccase (IL), immobilized versatile peroxidase (IP), as well as co-immobilized laccase (Lac) and versatile peroxidase (VP) with an enzyme activity recovery of about 79, 93, 27, and 27.5%, respectively. Similarly, the biocatalytic load of 116, 183, 23.6, and 31 U/g was obtained for IL, IP, and co-immobilized Lac and VP, respectively. The co-immobilized enzyme system exhibited better pH stability than the free and individual immobilized system by retaining more than 100% residual activity at pH 7.0 after a 150-h incubation; whereas, the thermal stability and kinetics of the co-immobilized biocatalyst were not much improved. IL and IP could be recycled for 10 cycles after which they retained 31 and 44% of their initial activities. Co-immobilized Lac and VP were reused for ten consecutive cycles at the end of which Lac activity was depleted, and 37% of VP activity was left. Free enzymes, IL, IP, co-immobilized Lac, and VP were applied to biorefinery wastewater (BRW) in a batch study to investigate the transformation of phenolic contaminants over a period of 5 days. The major classes of phenolic constituents in terms of their order of removal in a Lac-VP system was phenol >2-chlorophenol > trichlorophenol > dichlorophenol > cresols > dimethylphenol >2 methyl- 4, 6-dinitrophenol > 4-nitrophenol > tetrachlorophenols > pentachlorophenol. The free enzymes and individually immobilized enzymes resulted in 80% dephenolization in 5 days. By contrast, the co-immobilized biocatalyst provided rapid dephenolization yielding the same 80% removal within 24 h and 96% removal of phenols in 60 h after which the system stabilized, which is the major advantage of the co-immobilized biocatalyst. 相似文献
954.
Muthukkumar Thillainayagam Krishnamoorthy Venkatesan Rana Dipak Saravanan Subramani Balaji Sethuramasamyraja Rajesh Kumar Babu 《Environmental science and pollution research international》2017,24(20):16725-16734
In the Indian agricultural sector, millions of diesel-driven pump-sets were used for irrigation purposes. These engines produce carcinogenic diesel particulates, toxic nitrogen oxides (NOx), and carbon monoxide (CO) emissions which threaten the livelihood of large population of farmers in India. The present study investigates the use of n-propanol, a less-explored high carbon bio-alcohol that can be produced by sustainable pathways from industrial and crop wastes that has an attractive opportunity for powering stationary diesel engines meant for irrigation and rural electrification. This study evaluates the use of n-propanol addition in fossil diesel by up to 30% by vol. and concurrently reports the effects of exhaust gas recirculation (EGR) on emissions of an agricultural DI diesel engine. Three blends PR10, PR20, and PR30 were prepared by mixing 10, 20, and 30% by vol. of n-propanol with fossil diesel. Results when compared to baseline diesel case indicated that smoke density reduced with increasing n-propanol fraction in the blends. PR10, PR20, and PR30 reduced smoke density by 13.33, 33.33, and 60%, respectively. NOx emissions increased with increasing n-propanol fraction in the blends. Later, three EGR rates (10, 20, and 30%) were employed. At any particular EGR rate, smoke density remained lower with increasing n-propanol content in the blends under increasing EGR rates. NOx reduced gradually with EGR. At 30% EGR, the blends PR10, PR20, and PR30 reduced NOx emissions by 43.04, 37.98, and 34.86%, respectively when compared to baseline diesel. CO emissions remained low but hydrocarbon (HC) emissions were high for n-propanol/diesel blends under EGR. Study confirmed that n-propanol could be used by up to 30% by vol. with diesel and the blends delivered lower soot density, NOx, and CO emissions under EGR. 相似文献
955.
Ramesh Ramachandran Ajith Kumar Kolla S. Gopi Sundar Ravinder Singh Bhalla 《Ambio》2017,46(5):613-620
The relative impacts of hunting and habitat on waterbird community were studied in agricultural wetlands of southern India. We surveyed wetlands to document waterbird community, and interviewed hunters to document hunting intensity, targeted species, and the motivations for hunting. Our results show that hunting leads to drastic declines in waterbird diversity and numbers, and skew the community towards smaller species. Hunting intensity, water spread, and vegetation cover were the three most important determinants of waterbird abundance and community structure. Species richness, density of piscivorous species, and medium-sized species (31–65 cm) were most affected by hunting. Out of 53 species recorded, 47 were hunted, with a preference for larger birds. Although illegal, hunting has increased in recent years and is driven by market demand. This challenges the widely held belief that waterbird hunting in India is a low intensity, subsistence activity, and undermines the importance of agricultural wetlands in waterbird conservation. 相似文献
956.
Biswajit Kamila Anup Kumar Sadhukhan Prabir Basu Bharat Regmi Animesh Dutta 《International Journal of Green Energy》2017,14(13):1119-1129
A two-dimensional (2-D) model is developed to predict the torrefaction behavior of a large wet biomass particle. Although one-dimensional (1-D) model is found to be adequate for L/D ≥ 6, the necessity of using 2-D model at lower L/D ratios and higher torrefaction temperature is established. Errors up to 18% are observed in predicted mass fractions between 1-D and 2-D models. The center temperatures differed more, up to 96%, between z = 0 and z = L/2 in 2-D model which is not captured by the 1-D model. The model predictions agree well with the experimental results of the present authors and others. The evolution of the temperature profile is found to govern the mass fraction profile. At higher reactor temperature, three distinct zones are visible in the contour plots: peripheral fully torrefied zone, intermediate torrefying zone, and core with unreacted virgin biomass zone. Simulation studies show the formation of two symmetric annular hot spots at the ends, which move inward axially and subsequently merge at the center, the rate being faster for smaller L/D ratio. However, 1-D model does not provide such insight. The effects of reactor temperature, particle size, the residence time, and the initial moisture content on the torrefaction behavior are investigated. 相似文献
957.
This paper aims at analyzing the feasibility of a waste heat recovery power generation plant based on parametric optimization and performance analysis using different organic Rankine cycle configurations and heat source temperature conditions with working fluid R-12, R-123, R-134a, and R-717. A parametric optimization of turbine inlet temperature(TIT) was performed to obtain the irreversibility rate, system efficiency, availability ratio, turbine work output, system mass flow rate, second-law efficiency, and turbine outlet quality, along the saturated vapor line and also on superheating at an inlet pressure of 2.50 MP in basic as well as regenerative organic Rankine cycle. The calculated results reveal that selection of a basic organic Rankine cycle using R-123 as working fluid gives the maximum system efficiency, turbine work output, second-law efficiency, availability ratio with minimum system irreversibility rate and system mass flow rate up to a TIT of 150°C and appears to be a choice system for generation of power by utilizing the flue gas waste heat of thermal power plants and above 150°C the regenerative superheat organic Rankine cycle configuration using R 123 as working fluid gives the same results. 相似文献
958.
Nunn Patrick D. Runman John Falanruw Margie Kumar Roselyn 《Regional Environmental Change》2017,17(4):959-971
Regional Environmental Change - The characterization of Pacific Islands as especially vulnerable to climate change often undervalues the cultural resilience of their inhabitants. On many... 相似文献
959.
The effect of 24-epibrassinolide seed soaking on imidacloprid residues in green pods and mature seeds of Brassica juncea L. plants was investigated. The activities of the antioxidative enzymes glutathione-S-transferase, glutathione peroxidase, glutathione reductase, ascorbate peroxidase and guaiacol peroxidase, and the content of glutathione were determined. Imidacloprid residues in green pods were analyzed and quantified by gas chromatography-mass spectrometry, revealing that 24-epibrassinolide treatment resulted in a decrease of residues by almost 30%. In mature seeds, no pesticide residues were detected. Activities of all the antioxidative enzymes and glutathione content were found to be high in plants grown in soil amended with 300 mg imidacloprid kg?1 soil, but pre-soaking with 100 nmol L?1 24-epibrassinolide further enhanced the activities of all these enzymes and the glutathione content. 相似文献
960.
Chugh Priya Kaur Jaspreet Soni Raman Sharma Apurav Soni Sanjeev Kumar 《Journal of Material Cycles and Waste Management》2023,25(1):359-375
Journal of Material Cycles and Waste Management - The study deals with the management of deoiled rice bran by converting it into ethanol using a multi-enzyme preparation produced in-house... 相似文献