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1.
Extensive and indiscriminate use of synthetic compounds and natural compounds obtained from plant sources have resulted in serious threats to the aquatic ecosystem and human health. Aqueous extract of the root of the plant, Milletia pachycarpa Benth, is currently used for killing fish in the state of Manipur, India. Moreover, this plant is also used as traditional medicine in this region. Although it is widely used in traditional medicine, there is limited information available regarding the adverse effects and mechanism underlying its toxicity. This study examined the effects of exposure to aqueous extract of M. pachycarpa (AEMP) on early embryonic development of zebrafish embryos and mechanisms underlying toxicity. Zebrafish embryos treated with different concentrations of the AEMP produced embryonic lethality and developmental defects. The 96-hr-LC50 of AEMP was found to be 4.276 µg/mL. Further, multiple developmental abnormalities such as pericardial edema, yolk sac edema, spinal curvature, swim bladder deflation, decreased heart rate, and delayed hatching were also observed in a dose-dependent manner. Zebrafish embryo showing moderate-to-severe developmental defects following AEMP exposure cannot swim properly. Further, this study examined oxidative stress and apoptosis in embryos exposed to AEMP. Enhanced production of ROS and apoptosis was found in brain, trunk, and tail of zebrafish embryos treated with AEMP. Data suggest that oxidative stress and apoptosis are associated with AEMP-induced embryonic lethality and developmental toxicity in zebrafish embryos. 相似文献
2.
Assessment of petroleum hydrocarbon in a tropical brackish water lagoon: Chilika,India 总被引:1,自引:0,他引:1
Bita Mohanty Alaya Tarak Behera Debasish Mahapatro Saroja Kumar Barik Subir Kumar Nag 《Chemistry and Ecology》2016,32(7):653-668
Assessment of petroleum hydrocarbon (PHC) in the Chilika Lagoon, India, revealed a significant spatio-temporal variation in surface water (analysis of variance: n?=?120, p?.01), whereas insignificant variation in sediment samples. The lagoon exhibited the highest PHC concentration during summer, attributed to higher boat activity and mixing of PHC from bottom sediment. For PHC in both the water of the lagoon and regions adjacent to jetties, the northern sector exhibited highest concentrations, followed by the southern, outer channels and central sectors, in order. The highest PHC level was due to the highest density of fishing boat operations and maintenance activities, as well as the resuspension of lake sediments across the shallowest region of the lagoon. The PHC found in the water and sediment in the jetty regions were relatively high in comparison to the rest of the lagoon, again attributed to the maintenance and operational activities of the motorised boats in the jetties. The sediment PHC concentration was ~1000 times higher than the respective value for water, which could result from long-term deposition. The overall PHC concentration in the lagoon and jetties was found to be under the threshold limit and hence there is no risk to the existing biodiversity of the Chilika Lagoon. 相似文献
3.
A study on abundance and distribution of mangrove species in Indian Sundarban using remote sensing technique 总被引:1,自引:0,他引:1
Sandip Giri Anirban Mukhopadhyay Sugata Hazra Sandip Mukherjee Deborupa Roy Subhajit Ghosh Tuhin Ghosh Debasish Mitra 《Journal of Coastal Conservation》2014,18(4):359-367
Conservation and management of Sundarban mangrove forest is difficult chiefly due to inaccessibility and hostile condition. Remote sensing serves as an important tool to provide up-to date baseline information which is the primary requirement for the conservation planning of mangroves. In this study, supervised classification by maximum likelihood classifier (MLC) has been used to classify LANDSAT TM and LANDSAT ETM satellite data. This algorithm is used for computing likelihood of unknown measurement vector belonging to unknown classes based on Bayesian equation. Image spectra for various mangrove species were also generated from hyperspectral image. During field visits, GPS locations of five dominant mangrove species with appreciable distribution were taken and image spectra were generated for the same points from hyperion image. The result of this classification shows that, in 1999 total mangrove forest accounted for 55.01 % of the study area which has been reduced to 50.63 % in the year 2010. Avicennia sp. is found as most dominating species followed by Excoecaria sp. and Phoenix sp. but the aerial distribution of Avicennia sp., Bruguiera sp. and Ceriops sp. has reduced. In this classification technique the overall accuracy and Kappa value for 1999 and 2010 are 80 % and 0.77, 85.71 % and 0.81 respectively. 相似文献
4.
Soumen Maji Debasish Pal Prashanth R. Hanmaiahgari Umesh P. Gupta 《Environmental Fluid Mechanics》2017,17(4):853-877
This present study reports the results of an experimental study characterizing thorough variation of turbulent hydrodynamics and flow distribution in emergent and sparsely vegetated open channel flow. An emergent and rigid sparse vegetation patch with regular spacing between stems along the flow and transverse directions was fixed in the central region of the cross-section of open channel. Experiments were conducted in subcritical flow conditions and velocity measurements were obtained with an acoustic Doppler Velocimetry system. Large variations of the turbulence intensities, Reynolds shear stress, turbulent kinetic energy and vortical motions are found in and around the vegetation patch. At any cross-section through the interior of the vegetation patch, streamwise velocity decreases with increase in streamwise length and the velocity profiles converge from the log-law to a linear profile with increasing slope. Time-averaged lateral and vertical velocities inside the vegetation patch increase with increasing streamwise distance and converge from negative values to positive values. Turbulence intensities interior of the sparse vegetation patch are more than those of without the vegetation patch. Similar to the trend of streamwise velocity profiles inside the vegetation, turbulence intensities and longitudinal-normal Reynolds shear stress profile decreases with streamwise direction. In the interior of the vegetation patch and downstream of the trailing edge, turbulent kinetic energy profiles are exhibiting irregular fluctuations and the maximum values are occurring in the outer layer. Analysis of flow distribution confirms sparse vegetation patch is inducing a serpentine flow pattern in its vicinity. At the leading edge, flow is rushing towards the right hand sidewall, and at the trailing edge, flow is turning to the left hand sidewall. In between the leading and trailing edges, the streamlines are following a zig-zag fashion at varied degree along the streamwise and lateral directions. Immediate upstream of the leading edge and in the interior of the vegetation patch, vortex motion is clearly visible and the vortices are stretched along the width of the channel with streamwise direction. 相似文献
5.
Das Debasish Kumar Islam Md. Sariful Hadiujjaman Sheikh Dutta Champa Bati Morshed Md. Manjur 《Environmental Economics and Policy Studies》2019,21(3):371-397
Environmental Economics and Policy Studies - This study estimates health cost of salinity contamination in drinking water in the severe salinity affected three south-western districts of... 相似文献
6.
Here we propose a theoretical model to compute the suspended grain-size distribution in fluvial environment. We derive the model based on the Reynolds averaged Navier–Stokes equation and the continuity equation of sediment phase. The model includes the effects of secondary current and stratification which are the cause of complex interaction between turbulence and grain-size distribution in the sediment-laden flow. Due to an immense importance of particle–particle and particle-turbulence interactions near the channel bed, we include their impacts in the boundary condition of the model. The present model has noteworthy contribution to demonstrate the phenomena of suspended grain-size distribution in the real world. Reported experimental data in literature shows well agreement with the numerical solution computed from the suggested model. The better computational accuracy of the present model is ascertained when the upper bound of calculated error between observed experimental data and computed values is found to be lowest for our model in comparison to a large number of existing models developed from different mathematical viewpoints. 相似文献
7.
The present work deals with the As(Ⅴ) removal from an aqueous medium by calcined refractory grade bauxite (CRB) as a function of solution pH, time, As(Ⅴ) concentration and temperature. The residual As(Ⅴ) was lowered from 2 mg/L to below 0.01 mg/L in the optimum pH range 4.0-7.0 using a 5 g/L CRB within 3 h contact time. The adsorption data fits well with Langmuir isotherm and yielded Langmuir monolayer capacity of 1.78 mg As(Ⅴ)/g of CRB at pH 7.0. Presence of anions such as silicate and phosphate decreased As(Ⅴ) adsorption efficiency. An increase temperature resulted a decrease in the amount of As(Ⅴ) adsorbed by 6%. The continuous fixed bed column study showed that at the adsorbent bed depth of 30 cm and residence time of 168 min, the CRB was capable of treating 340 bed volumes of As(V) spiked water (C0 = 2 mg/L) before breakthrough (Ce = 0.01 mg/L). This solid adsorbent, although not reusable, can be considered for design of adsorption columns as an efficiency arsenic adsorption media. 相似文献
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Debasish Paul J.C. Majumdar Debasis Ghose R.C. Sastri 《Environmental geochemistry and health》2002,24(4):321-325
Limestone is an item most commonly consumed by the people in the Barak Valley area of Assam along with betel leaves. Also limestone chips are extensively used for water treatment in filter beds of these areas. A preliminary investigation on the activity of the samples of limestone, collected from the local market at Silchar, Assam, indicated the presence of beta and gamma-ray activity, prompting further investigations for the presence of alpha particle emitting radionuclides. Also the study of the ionising emissions from these samples using solid state nuclear track detector (SSNTD) has revealed the presence of spontaneous fission fragments along with alpha particles. This paper presents an account of the results obtained from the SSNTD studies of these limestone samples. 相似文献
10.
Debasish Guha Thakurata Krishna Chandra Das Arijita Paul Siddhartha Sankar Dhar 《环境质量管理》2023,32(3):69-78
Toxic organic dyes released into aquatic sources as a result of industrial activities pose a significant threat to the environment. The removal of such dyes from water sources is a challenging task in the context of environmental emergencies. In this present effort, the strontium ferrite nanoparticles were synthesized by coprecipitation followed by a calcination method and is applied for photocatalytic degradation of such organic dyes. The ferrite nanoparticles were characterized by FTIR, XRD, VSM, SEM-EDX, TEM, and HR-TEM studies. In the existence of H2O2 under visible light, the catalyst performs efficient degradation of aniline blue (AB) and methyl violet (MV) dyes in a remarkably short interval of time. The superparamagnetic performance of the catalyst was confirmed by VSM, and thus it can be easily recovered from the degraded dye by applying an external magnet. The Fenton mechanism justifies the elevated rate of photo degradation, which generates hydroxyl and perhydroxyl radicals in the progress of the reaction. 相似文献