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431.
Deepak Kumar A. Rajeshwari Pradeep Singh Jadon Gouri Chaudhuri Anita Mukherjee Natarajan Chandrasekaran Amitava Mukherjee 《环境科学学报(英文版)》2015,38(12):150-157
The current study evaluates the cytogenetic effects of chromium (III) oxide nanoparticles on the root cells of Allium cepa. The root tip cells of A. cepa were treated with the aqueous dispersions of Cr2O3 nanoparticles (NPs) at five different concentrations (0.01, 0.1, 1, 10, and 100 μg/mL) for 4 hr. The colloidal stability of the nanoparticle suspensions during the exposure period were ascertained by particle size analyses. After 4 hr exposure to Cr2O3 NPs, a significant decrease in mitotic index (MI) from 35.56% (Control) to 35.26% (0.01 μg/mL), 34.64% (0.1 μg/mL), 32.73% (1 μg/mL), 29.6% (10 μg/mL) and 20.92% (100 μg/mL) was noted. The optical, fluorescence and confocal laser scanning microscopic analyses demonstrated specific chromosomal aberrations such as—chromosome stickiness, chromosome breaks, laggard chromosome, clumped chromosome, multipolar phases, nuclear notch, and nuclear bud at different exposure concentrations. The concentration-dependent internalization/bio-uptake of Cr2O3 NPs may have contributed to the enhanced production of anti oxidant enzyme, superoxide dismutase to counteract the oxidative stress, which in turn resulted in observed chromosomal aberrations and cytogenetic effects. These results suggest that A. cepa root tip assay can be successfully applied for evaluating environmental risk of Cr2O3 NPs over a wide range of concentrations. 相似文献
432.
Kumar A Miglani P Gupta RK Bhattacharya TK 《Journal of environmental biology / Academy of Environmental Biology, India》2006,27(1):61-66
A study was conducted on anaerobic digestion of potato waste and cattle manure mixture, inoculated with 12% inoculum and diluted to 1:1 substrate water ratio at 37 +/- 1 degrees C. Initially pH of substrate was found to be 4.5 to 5.0. Lime and sodium bicarbonate solutions were employed to adjust the pH to 7.5. Biogas production continued up to 10 and 7 days, when lime and sodium bicarbonate solutions were used to adjust the pH, respectively. Biogassification potential was studied in response to different ratio of waste and cattle manure. Biogas production rate was higher when potato waste and cattle manure were used in 50:50 ratio. Effect of two different concentrations (2.5 and 5.0 ppm) of three heavy metals viz. (Ni (II), Zn (II) and Cd (II)) on anaerobic digestion of substrate (potato waste--cattle manure, 50:50) was studied. At 2.5 ppm, all the three heavy metals increased biogas production rate over the control value. The percentage increase in biogas production over the control was highest by Cd, followed by Ni and Zn. In all the treatments, methane content of biogas increased with increase in time after feeding. Various physico-chemical parameters viz. total solids, total volatile solids, total organic carbon and chemical oxygen demand considerably declined after 7 days of digestion and decline was greater in presence of heavy metals as compared to control. The physico-chemical parameters revealed maximum decrease in the presence of 2.5-ppm concentrations of heavy metals with the substrate. Among all the three heavy metals employed in the study, Cd++ at 2.5 ppm was found to produce maximum biogas production rate. The use of three heavy metals to enhance biogas production from potato and other horticultural waste is discussed. 相似文献
433.
Compost was prepared from wheat straw enriched with Rajasthan rock phosphate and Aspergillus awamori. The resulting phospho-compost along with phosphorus enriched FYM, mineral fertilizer (rock phosphate) and super phosphate were evaluated for their individual contribution in improving organic matter status, P availability, and enzymatic activities of soil under wheat crop grown in a micro plot. The results showed that total organic carbon, nitrogen, microbial biomass, and humus content (an index of organic matter status of soil) of soil was highest when farm yard manure (FYM) after its enrichment with 12.5% rock phosphate was applied. Microbial enriched phospho-compost was the product yielding highest soil available phosphorus, phosphorus uptake, urease, and cellulase activities. However, FYM amended with 25% rock phosphate resulted in the greatest enhancement of beta- glucosidase. Measured parameters indicated a sure improvement of chemical and biological activities of soil after the application of phosphorus enriched organic amendments compared to the commercial fertilizer commonly used by the Indian farmers. 相似文献
434.
Photodegradation of alphacypermethrin ((RS)-alpha cyano-3-phenoxy benzyl (1RS) cis-3-(2,2,dichlorovinyl)-2,2-dimethyl cyclopropane carboxylate) was studied as a thin film on glass surface and on black and red soil surfaces. A number of photoproducts from glass surfaces have been isolated, characterized and identified by gas chromatography-mass spectroscopy (GC-MS). However, only two of them viz. 3-phenoxy benzyl alcohol and [2,2-dichlorovinyl-3(2,2,dimethyl) cyclopropane carboxylate] could be identified from both the soil. Rate of photodegradation on glass and soil surface under UV and sunlight followed first order kinetics with significant correlation coefficients. The rate of photodegradation was greater on black than on red soil. 相似文献
435.
436.
Harish Kumar Jeswani Adisa Azapagic Philipp Schepelmann Michael Ritthoff 《Journal of Cleaner Production》2010,18(2):120-127
Life Cycle Assessment (LCA) has matured over the past decades and become part of the broader field of sustainability assessment. To strengthen LCA as a tool and eventually increase its usefulness for sustainability decision-making, it is argued that there is a need to expand the ISO LCA framework by integration and connection with other concepts and methods. This paper explores the potential options for deepening and broadening the LCA methodologies beyond the current ISO framework for improved sustainability analysis. By investigating several environmental, economic and social assessment methods, the paper suggests some options for incorporating (parts of) other methods or combining with other methods for broadening and deepening the LCA. 相似文献
437.
Koustubh M. Vaze Nisha N. Kannan L. Abhilash Vijay Kumar Sharma 《Die Naturwissenschaften》2012,99(11):967-971
Morning and evening chronotypes of sleep/wake cycles in humans are often metaphorically termed as ‘larks’ and ‘owls’. We derived Drosophila populations early and late, displaying lark- and owl-like emergence chronotypes by imposing selection for adult emergence during morning and evening hours. Preference for morning and evening emergence in these populations was accompanied by divergence in their circadian period (τ) and photic phase response curve. To test if lark- and owl-like emergence chronotypes displayed by these flies under weak environmental cycles of the laboratory would also persist in nature where several zeitgebers are present in the strongest form, we examined the emergence rhythm of early and late flies under semi-natural conditions. The early and late flies not only continued to exhibit divergent emergence waveforms under semi-natural conditions, the differences became even more prominent. However, phases of early and late emergence waveforms did not match natural morning and evening transitions, unlike that observed under laboratory conditions. These results thus provide evidence consistent with the notion that chronotypes are the result of interactions between circadian clocks and natural environmental cycles. 相似文献
438.
The need for environmental and urban planning reached a critical point in the year 2007, when one-half of the world's population
could be defined as living in cities. Urbanisation in India is also increasing at a fast rate. Urban chaos in India, emanating
from the continuous ignorance of fragile ecosystems, calls for the reshaping of existing cities as ‘eco-cities’. The ‘eco-city’—a
well-known concept in the western world—is new to the Indian context. While western connotations of eco-cities should not
be discarded outright in the context of India, core concerns vary significantly for obvious reasons. Recognising two facts—firstly,
eco-city development is altogether a fresh approach to human settlement development in India, and, secondly, the manifold
increase in the vulnerability of cities—this paper discusses documented good practice, reinforcing evolution towards the eco-city
vision. Lessons drawn from the examples cited are further deconstructed in the light of their contribution to urban risk reduction,
which provides direction to appreciating the ‘disaster-resilient eco-community’ concept in Puri, a coastal city in India.
Further, this paper attempts to unravel existing community-based practices in Puri, which are boon to the local environment
and invariably reduce disaster risk. These seemingly modest neighbourhood initiatives symbolise immense societal wealth, which
can be calibrated appropriately for reducing urban environmental risk as well. This paper also illustrates how a ‘disaster
resilient eco-community’ approach is inevitable in the present and future contexts not only to preserve sustainable development
gains but also to secure human well-being. 相似文献
439.
Phosphorus removal in vegetated filter strips 总被引:5,自引:0,他引:5
Abu-Zreig M Rudra RP Whiteley HR Lalonde MN Kaushik NK 《Journal of environmental quality》2003,32(2):613-619
Vegetated filter strips (VFS) are used recently for removal, at or near the source, of sediment and sediment-bound chemicals from cropland runoff. Vegetation within the flowpath increases water infiltration and decreases water turbulence, thus enhancing pollutant removal by sedimentation within filter media and infiltration through the filter surface. Field experiments have been conducted to examine the efficiency of vegetated filter strips for phosphorus removal from cropland runoff with 20 filters with varying length (2 to 15 m), slope (2.3 and 5%), and vegetated cover, including bare-soil plots as control. Artificial runoff used in this study had an average phosphorus concentration of 2.37 mg L(-1) and a sediment concentration of 2700 mg L(-1). The average phosphorus trapping efficiency of all vegetated filters was 61% and ranged from 31% in a 2-m filter to 89% in a 15-m filter. Filter length has been found to be the predominant factor affecting P trapping in VFS. The rate of inflow, type of vegetation, and density of vegetation coverage had secondary influences on P removal. Short filters (2 and 5 m), which are somewhat effective in sediment removal, are much less effective in P removal. Increasing the filter length beyond 15 m is ineffective in enhancing sediment removal but is expected to further enhance P removal. Sediment deposition, infiltration, and plant adsorption are the primary mechanisms for phosphorus trapping in VFS. 相似文献
440.
Microbial degradation of pyridine using Pseudomonas sp. and isolation of plasmid responsible for degradation 总被引:11,自引:0,他引:11
Mohan SV Sistla S Guru RK Prasad KK Kumar CS Ramakrishna SV Sarma PN 《Waste management (New York, N.Y.)》2003,23(2):167-171
Pseudomonas (PI2) capable of degrading pyridine was isolated from the mixed population of the activated sludge unit which was being used for treating complex effluents, the strain was characterized. Aerobic degradation of pyridine was studied with the isolated strain and the growth parameters were evaluated. Pyridine degradation was further conformed by chromatography (HPLC) analysis. The process parameters like biomass growth and dissolved oxygen consumption were monitored during pyridine degradation. In order to conform with the plasmid capability to degrade pyridine, the requisite plasmid was isolated and transferred to DH 5alpha Escherichia coli. The subsequent biodegradation studies revealed the ability of the transformed plasmid capability to degrade the pyridine. 相似文献