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161.
Sen Ruchira Malhotra Kunika Gupta Manisha Kaur Rajbir Bawa Divya Duhan Meghna Sandhi Sonia Songara Pratibha Nain Deepak Raychoudhury Rhitoban 《Die Naturwissenschaften》2022,109(3):1-5
The Science of Nature - Leaf-cutting ants are highly successful herbivores in the Neotropics. They forage large amounts of fresh plant material to nourish a symbiotic fungus that sustains the... 相似文献
162.
Male albino rats were administered Cd and HCH daily for six weeks to study the effect of Cd on storage and metabolism of HCH. The results indicated a marked inhibition of the metabolism of HCH in the group dosed with HCH + Cd. The metabolic rate of HCH in the group dosed with HCH + Cd was also significantly lower than that in the group dosed with HCH alone. The hepatic content of Cd and Zn was significantly increased whereas a marked depletion of Cu and Fe was observed in the groups exposed to Cd and HCH + Cd. A high level of free Cd and Zn or a low level of Fe and Cu in liver seemed to play an important role in the metabolic inhibition observed in this study. 相似文献
163.
This study attempted to determine the effects of heavy metals on the photosynthetic blue-green algae for their potential to use as a biosensor. The bioaccumulation of metals and its effects on pigments of Nostoc muscorum and Synechococcus PCC 7942 were assessed. The culture was grown in BG 11 liquid medium supplied with different metals like mercury (Hg), lead (Pb), and cadmium (Cd) and incubated (µM 20 concentrations) for 10 days under optimal conditions. The accumulated amounts of metals were determined by atomic absorption spectroscopy (AAS). The stress effects on photosynthetic pigment chlorophyll a (Chl a) were monitored by laser-induced fluorescence (LIF). Bio-concentration factor (BCF) reached a peak in cells on the 2nd day of incubation followed by a gradual reduction. The highest reduction in the pigment concentrations (Chl a and β carotene) was observed at 20?µM?L?1 Hg treatment. The results indicate that, cyanobacteria may serve as both potential species to be used as a biosensor and used to clean up heavy metals from contaminated water. These changes were analyzed with the long-term goal of exploiting cyanobacterial cells as biosensors. 相似文献
164.
Sayan Bhattacharya Kaushik Gupta Sushanta Debnath Uday Chand Ghosh Dhrubajyoti Chattopadhyay Aniruddha Mukhopadhyay 《毒物与环境化学》2013,95(3):429-441
Arsenic (As) is a metalloid that poses serious environmental threats due to its behemoth toxicity and wide abundance. The use of arsenic-contaminated groundwater for irrigation purpose in crop fields elevates arsenic concentration in surface soil and in the plants. In many arsenic-affected countries, including Bangladesh and India, rice is reported to be one of the major sources of arsenic contamination. Rice is much more efficient at accumulating arsenic into the grains than other staple cereal crops. Rice is generally grown in submerged flooded condition, where arsenic bioavailability is high in soil. As arsenic species are phytotoxic, they can also affect the overall production of rice, and can reduce the economic growth of a country. Once the foodstuffs are contaminated with arsenic, this local problem can gain further significance and may become a global problem, as many food products are exported to other countries. Large-scale use of rainwater in irrigation systems, bioremediation by arsenic-resistant organisms and hyperaccumulating plants, and the aerobic cultivation of rice are some possible ways to reduce the extent of bioaccumulation in rice. Investigation on a complete food chain is urgently needed in the arsenic-contaminated zones, which should be our priority in future researches. 相似文献
165.
Fluorosis is a serious public health problem in many parts of the world. The generation of reactive oxygen species and lipid peroxidation has been considered to play an important role in the pathogenesis of chronic fluoride toxicity. The present study was undertaken to evaluate the protective effect of Tamarindus indica fruit pulp extract on the collagen content and oxidative stress in liver and kidney of fluoride-exposed rats. The first group served as control. The second group received 200 mg L?1 of sodium fluoride through drinking water. The third and fourth groups received T. indica fruit pulp extract (200 mg kg?1 body weight) alone and along with fluorinated drinking water respectively, daily by gavage for a period of 90 days. At the end of the experiment, blood samples were collected from all groups, and liver and kidney samples were taken concurrently. Levels of malondialdehyde and glutathione and the activities of superoxide dismutase and catalase were evaluated in the liver and kidney of experimental rats. Furthermore, level of hydroxyproline and histological examination of liver and kidney along with serum biochemical parameters were evaluated. In conclusion, fluoride was determined to cause adverse effects in rats, and the supplementation of tamarind to these animals alleviated the adverse effects of fluoride. 相似文献
166.
Partitioning of native or anthropogenic heavy metals in solid and solution phases of soil is a result of network of several physico‐chemical reactions. The attainment of equilibrium between two phases is also regulated by biochemical processes. For practical purposes, the bioavailability of metal present in soil is predominantly regulated by the soil solution phase which is in dynamic equilibrium with the solid phase. The results of a model laboratory and greenhouse growth experiments have been used to investigate the effect of Cd‐ion concentrations (either in soil solution or in nutrient solution) on the growth and activities of microorganisms. The soil solution has been simulated by preparing a suspension of soil with 0.1 M NaNO3 (1: 2.5) equilibrated for two hours. Important conclusions are as follows: Increase in Cd‐ion concentration in soil solution or in nutrient solution induces corresponding adverse effect on the growth and activities of microorganisms. Thus, it seems that Cd‐ion concentration is a more sensitive indicator for assessing the effect of metal pollution upon the growth and activities of soil microorganisms in comparison to total Cd contents. During active microbial growth phase, a large part of the organically bound Cd was released in the soil solution which is largely bioavailable. This process is termed as mobilisation. There was momentary increase of Cd‐ion concentration in soil solution which intoxicated the growing organisms. After this stage, the Cd ions from the solution phase were removed by the newly formed solid phase (nonviable biomass) and were transformed in non‐available form. This process is termed as immobilisation. The consequences and importance of these results for practical agriculture and in deciding the limits or guidelines on the maximum tolerable metal load in soils are discussed. 相似文献
167.
Poddar Nanda Das Susmita Dhar Subham Mondal Kajal Kumar 《Environmental Fluid Mechanics》2021,21(5):1069-1090
Environmental Fluid Mechanics - Predicting the evolution of environmental dispersion of settling particles in wetland flows has a wide range of applications in ecological engineering. In the... 相似文献
168.
Biodegradation is an attractive approach for the elimination of synthetic polymers, pervasively accumulated in natural environments and generating ecological problems. The present work investigated the degradation of low‐density polyethylene (PE) by three Bacillus sp., that is, ISJ36, ISJ38, and ISJ40. The degree of biodegradation was assessed by measuring hydrophobicity, viability, and total protein content of bacterial biofilm attached to the PE surface. Although all three bacterial strains were able to establish an active biofilm community on the PE surface, ISJ40 showed better affinity toward PE degradation than the other two. Bacterial colonization and physical changes on the PE surface were visualized by scanning electron microscopy. Fourier transform infrared spectroscopy analysis revealed alteration in the intensities of functional groups along with an increase in the carbonyl bond indexes. The study results suggest that the Bacillus strain ISJ40 can be used as a potential degrader for the eco‐friendly treatment of PE waste. 相似文献
169.
Kanha Gupta Nitin Khandelwal Gopala Krishna Darbha 《Frontiers of Environmental Science & Engineering》2020,14(1):15
170.
B.R. Gurjar A. Jain A. Sharma A. Agarwal P. Gupta A.S. Nagpure J. Lelieveld 《Atmospheric environment (Oxford, England : 1994)》2010,44(36):4606-4613
This study evaluates the health risks in megacities in terms of mortality and morbidity due to air pollution. A new spreadsheet model, Risk of Mortality/Morbidity due to Air Pollution (Ri-MAP), is used to estimate the excess numbers of deaths and illnesses. By adopting the World Health Organization (WHO) guideline concentrations for the air pollutants SO2, NO2 and total suspended particles (TSP), concentration-response relationships and a population attributable-risk proportion concept are employed. Results suggest that some megacities like Los Angeles, New York, Osaka Kobe, Sao Paulo and Tokyo have very low excess cases in total mortality from these pollutants. In contrast, the approximate numbers of cases is highest in Karachi (15,000/yr) characterized by a very high concentration of total TSP (~670 μg m?3). Dhaka (7000/yr), Beijing (5500/yr), Karachi (5200/yr), Cairo (5000/yr) and Delhi (3500/yr) rank highest with cardiovascular mortality. The morbidity (hospital admissions) due to Chronic Obstructive Pulmonary Disease (COPD) follows the tendency of cardiovascular mortality. Dhaka and Karachi lead the rankings, having about 2100/yr excess cases, while Osaka-Kobe (~20/yr) and Sao Paulo (~50/yr) are at the low end of all megacities considered. Since air pollution is increasing in many megacities, and our database of measured pollutants is limited to the period up to 2000 and does not include all relevant components (e.g. O3), these numbers should be interpreted as lower limits. South Asian megacities most urgently need improvement of air quality to prevent excess mortality and morbidity due to exceptionally high levels of air pollution. The risk estimates obtained from Ri-MAP present a realistic baseline evaluation for the consequences of ambient air pollution in comparison to simple air quality indices, and can be expanded and improved in parallel with the development of air pollution monitoring networks. 相似文献