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61.
Devi Prasad Mishra Patitapaban Sahu Durga Charan Panigrahi Vivekanand Jha R. Lokeswara Patnaik 《Environmental science and pollution research international》2014,21(3):2305-2312
This paper presents a comparative study of 222Rn emanation from the ore and backfill tailings in an underground uranium mine located at Jaduguda, India. The effects of surface area, porosity, 226Ra and moisture contents on 222Rn emanation rate were examined. The study revealed that the bulk porosity of backfill tailings is more than two orders of magnitude than that of the ore. The geometric mean radon emanation rates from the ore body and backfill tailings were found to be 10.01?×?10?3 and 1.03 Bq m?2 s?1, respectively. Significant positive linear correlations between 222Rn emanation rate and the 226Ra content of ore and tailings were observed. For normalised 226Ra content, the 222Rn emanation rate from tailings was found to be 283 times higher than the ore due to higher bulk porosity and surface area. The relative radon emanation from the tailings with moisture fraction of 0.14 was found to be 2.4 times higher than the oven-dried tailings. The study suggested that the mill tailings used as a backfill material significantly contributes to radon emanation as compared to the ore body itself and the 226Ra content and bulk porosity are the dominant factors for radon emanation into the mine atmosphere. 相似文献
62.
M. Yokesh Babu L. Palanikumar N. Nagarani V. Janaki Devi S. Ramesh Kumar C. M. Ramakritinan A. K. Kumaraguru 《Environmental science and pollution research international》2014,21(16):9604-9616
Marine macroalgae have evolved a different mechanism to maintain physiological concentrations of essential metal ions and non-essential metals. The objective of the present work was to evaluate the antioxidant response and DNA damage of copper and cadmium ions in three halophytes, namely, Acanthophora spicifera, Chaetomorpha antennina, and Ulva reticulata. Accumulation of copper was significantly higher (P?0.05) than that of cadmium. Biochemical responses showed that copper was considerably more toxic than cadmium (P?0.05). Decreases in glutathione content and fluctuations of super oxide dismutase, catalase, and glutathione peroxidase activities were observed corresponding to time and concentration of exposure. Interestingly, it was also observed that antioxidant levels decreased as a result of metal accumulation, which may be due to free radicals generated by copper and cadmium in seaweeds. The present study also showed that copper and cadmium increased oxidative stress and induced antioxidant defense systems against reactive oxygen species. The order of toxicity for metals in the studied seaweeds was U. reticulata > A. spicifera > C. antennina. DNA damage index analysis supported that copper was significantly (P?0.05) more toxic than cadmium. Bioaccumulation, biochemical responses, and DNA damage observed in the here analyzed marine macroalgae after exposure to selected metals indicate that these marine organisms represent useful bioindicators of marine pollution. 相似文献
63.
An experiment was conducted under laboratory conditions to investigate the effect of two systemic herbicides viz., pendimethalin
and quizalofop, at their recommended field rates (1.0 kg and 50 g active ingredient ha − 1, respectively) on the growth and activities of non-symbiotic N2-fixing bacteria in relation to mineralization and availability of nitrogen in a Typic Haplustept soil. Both the herbicides, either singly or in a combination, stimulated the growth and activities of N2-fixing bacteria resulting in higher mineralization and availability of nitrogen in soil. The single application of quizalofop
increased the proliferation of aerobic non-symbiotic N2-fixing bacteria to the highest extent while that of pendimethalin exerted maximum stimulation to their N2-fixing capacity in soil. Both the herbicides, either alone or in a combination, did not have any significant difference in
the stimulation of total nitrogen content and availability of exchangeable NH4
+ while the solubility of NO3
− was highly manifested when the herbicides were applied separately in soil. 相似文献
64.
Agafonov L. I. Gurskaya M. A. Kukarskih V. V. Bubnov M. O. Devi N. M. Galimova A. A. 《Russian Journal of Ecology》2021,52(5):349-357
Russian Journal of Ecology - It has recently become a matter of discussion whether it is correct to use regional tree-ring chronologies in spatiotemporal climate reconstructions, since natural and... 相似文献
65.
Distribution of detoxifying genes polymorphism in Maharastrian population of central India 总被引:1,自引:0,他引:1
Saravana Devi S Vinayagamoorthy N Agrawal M Biswas A Biswas R Naoghare P Kumbhakar S Krishnamurthi K Hengstler JG Hermes M Chakrabarti T 《Chemosphere》2008,70(10):1835-1839
The present study is aimed at evaluating the genotype frequency of detoxifying genes such as GSTM1, GSTT1 and NQO1 in Maharastrian population of central India. The study revealed about 64.6% of GSTM1-positive and 35.4% GSTM1-null population. GSTT1-positive genotype was found to be 87.5% and GSTT1-null showed 12.5%. The NQO1 genotype of Maharastrian population showed 52.3% of C/C, 42.48% C/T and 5.18% T/T. The NQO1 of this population does not deviate from the expected Hardy-Weinberg equilibrium. The genotype frequencies GSTM1 and GSTT1 of the population when compared with other ethnic groups of Asia and Caucasians show distinct nature of Maharastrian population from other Asian and Caucasian population. 相似文献
66.
Spatial distribution,source apportionment and ecological risk assessment of residual organochlorine pesticides (OCPs) in the Himalayas 总被引:1,自引:0,他引:1
67.
There is a growing interest in management of MSW through micro-treatment of organic fraction of municipal solid wastes (OFMSW)
in many cities of India. The OFMSW fraction is high (>80%) in many pockets within South Indian cities like Bangalore, Chikkamagalur,
etc. and is largely represented by vegetable, fruit, packing and garden wastes. Among these, the last three have shown problems
for easy decomposition. Fruit wastes are characterized by a large pectin supported fraction that decomposes quickly to organic
acids (becomes pulpy) that eventually slow down anaerobic and aerobic decomposition processes. Paper fraction (newsprint and
photocopying paper) as well as paddy straw (packing), bagasse (from cane juice stalls) and tree leaf litter (typical garden
waste and street sweepings) are found in reasonably large proportions in MSW. These decompose slowly due to poor nutrients
or physical state. We have examined the suitability of these substrates for micro-composting in plastic bins by tracking decomposition
pattern and physical changes. It was found that fruit wastes decompose rapidly to produce organic acids and large leachate
fraction such that it may need to be mixed with leachate absorbing materials (dry wastes) for good composting. Leaf litter,
paddy straw and bagasse decompose to the tune of 90, 68 and 60% VS and are suitable for composting micro-treatment. Paper
fractions even when augmented with 10% leaf compost failed to show appreciable decomposition in 50 days. All these feedstocks
were found to have good biological methane potential (BMP) and showed promise for conversion to biogas under a mixed feed
operation. Suitability of this approach was verified by operating a plug-flow type anaerobic digester where only leaf litter
gathered nearby (as street sweepings) was used as feedstock. Here only a third of the BMP was realized at this scale (0.18 m3 biogas/kg VS 0.55 m3/kg in BMP). We conclude that anaerobic digestion in plug-flow like digesters appear a more suitable micro-treatment option
(2–10 kg VS/day) because in addition to compost it also produces biogas for domestic use nearby. 相似文献
68.
Observations on the pattern of blood circulation in eggs and early larvae of Ambassis, Mugil, Dorosoma and Thrissocles species have been made. In the initial stages, the tubular heart lies on the left side, near the cephalic region. The anterior end of the heart lies near the snout. The posterior end is attached to a point mid-way between the orbits and auditory vesicles; the position of the anterior end is greatly influenced by the size of yolk. Initially, the tubular heart and dorsal aorta lie in a line. As a result of yolk absorption, the anterior end of the tubular heart gradually sinks to a position posterior to the attached end. Liquified yolk is circulated through the heart in early stages; blood corpuscles become apparent only in larvae. The heart-beat, which is initially irregular, gradually becomes regular as development progresses. In the initial stages the blood flows to the caudal and not to the cephalic region. The blood vessels are narrow, and the oval-shaped blood corpuscles must therefore pass through individually, with their long axes parallel to the passage. A definite capillary system is not evident. The blood vessels can dilate and contract when required. 相似文献
69.
Environmental Fluid Mechanics - Species specific hydrodynamic characterization is essential for assessing the suitability of various types of mangroves in coastal protection as the dissipation of... 相似文献
70.