Effects of a low-radiotoxicity uranium salt (uranyl acetate) on biochemical and hematological parameters of the catfish, <Emphasis Type="Italic">Clarias gariepinus</Emphasis>

Specimens of Clarias gariepinus were treated with lethal (70, 75, 80, 85, 90, and 95 mg/L) and sub-lethal concentrations (8, 12 and 16 mg/L) of uranyl acetate, a low-radiotoxicity uranium salt. The LC 50 value was registered as 81.45 mg/L. The protein and glycogen concentrations in liver and muscles were decreased in the fish exposed to sub-lethal concentrations. The red blood cell (RBC) and white blood cell (WBC) counts, haemoglobin (Hb) concentration and haematocrit (Hct) values were decreased. Different blood indices like mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were negatively affected. Level of plasma glucose was elevated whereas protein was decreased. The level of calcium concentration (Ca) was declined in the blood of exposed fish whereas magnesium (Mg) remains unchanged. The activity level of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) was elevated in exposed fish. These effects were more pronounced in the last period of exposure and in higher concentrations. Results of the present study indicate that uranyl acetate has adverse effects on Clarias gariepinus and causes changes in the biochemical and hematological parameters of the fish.     

BIOMONITORING OF AMBIENT CONCENTRATIONS OF CADMIUM,COPPER, LEAD AND ZINC IN THE COASTAL WETLAND WATER BY USING GILLS OF THE GREEN- LIPPED MUSSEL PERNA VIRIDIS

1 INTRODUCTIONThe use of marine mussels for the biomonitoringpurposes is widely found in the literatures. However,the use of a particular tissue/organ for more accurateindicators of metal bioavailability and contaminationwere continually reported. For exa…     

The mechanics of a magma chamber-fault system in trans-tension with application to Coso

The mechanical interaction between an elliptically shaped magma chamber and a fault subject to transtension is investigated with particular reference to the Coso geothermal field. The geologic setting of the Coso field is interpreted as a releasing bend step-over structure formed by the Airport Lake and Owens Valley dextral strike-slip fault system. The role of the Coso volcano-magmatic center in the development of the “over-step” structure is examined by treating the magma chamber as a liquid inclusion in a viscoelastic crust containing a fault (Airport Lake). The problem is numerically solved using a 2D viscoelastic finite element model with thermally activated viscosity to account for thermal weakening of the rock. The temperature distribution around the magma body is calculated based on a 3D steady-state approach and using the mesh-less numerical method. The fault is modeled as a frictionless contact. The simulated distributions of stress and strain around the inclusion display a rotation caused by the shearing component of the applied transtension. The results indicate that the fault tends to overstep the chamber in a geometric pattern similar to a step-over. There is good correspondence between the computed distributions of the maximum shear stress in the vicinity of the magma chamber and the map of earthquake epicenters at a depth of 7–10 km in Coso.     

A nonlinear polar coordinate shallow water model for tsunami computation along North Sumatra and Penang Island

A nonlinear shallow water model in cylindrical polar coordinate system is developed, using an explicit finite difference scheme with a very fine resolution, to compute different aspects of tsunami at North Sumatra and the adjacent island Simeulue in Indonesia, and the Penang Island in Peninsular Malaysia. The pole of the frame is placed on the mainland of Penang (100.5°E) and the model area extends up to the west of Sumatra (87.5°E). The model is applied to simulate the propagation of tsunami wave towards North Sumatra, Simeulue and Penang Islands associated with Indonesian tsunami of 26 December 2004. The model is also applied to compute water levels along the coastal belts of those islands. Computed and observed water level data are found to be in good agreement and North Sumatra is found to be vulnerable for very high surges. The computed and observed arrival times of high surges are also in reasonable agreement everywhere. Further studies are carried out to investigate the effect of convective terms and it is found that their effects are insignificant in tsunami propagation and weakly significant for wave amplitude very near to the coast.     

Flood traps through space and time and their bearing on some problems of geotectonics

A study of world stratigraphy reveals, somewhat unexpectedly, that there were extensive basalt flows in the early Precambrian, but the Upper Precambrian and the whole of the Palaeozoic Era, with some insignificant exceptions, are practically devoid of flood basalts. In fact there were very few cruptions between about 1000 M.yr. and about 200 M.yr, ago. Since Upper Triassic time, however, basalt floods have come to cover very extensive areas in both the hemispheres, and the activity is continuing almost unabated. Recent researches on the origin and nature of the mid-ocean ridges have indicated that the flood basalts are apparently genetically connected with these ridges which appear to have begun to open the present oceans within the past 150 M.yr. Basalts occur on the opposite coasts where the continents were formerly together, for example, Peninsular India and Eastern Africa. However, along certain coastal areas there are no basalts of appropriate age even though a mid-ocean ridge exists beyond these. This is true, for example, of eastern North America and western Europe. Elsewhere neither basalt flows nor a mid-oceanic ridge exist where the continents are reasonably believed to have been together. These anomalies call for an explanation, and it is suggested that the observed features can be explained by the fact that two distinct phenomena, crustal sliding and global expansion, have been responsible for the present disposition of the continents. The net result of these two activities has been recognised as ‘Continental Drift’.     

Changing land use/land cover patterns and growing human population in Wular catchment of Kashmir Valley,India

GeoJournal - The profound increase in human activities and the degrading scenario in fragile ecosystems of the western Himalayas like that of Wular Lake have highlighted the need to analyze the...     

Sustainable Improvement of Tropical Residual Soil Using an Environmentally Friendly Additive

Many tropical residual laterites have relatively poor engineering properties due to the significant percentage of fine-grained soil particles that they contain, which are formed by the soil weathering process. The widespread presence of laterite soils in tropical regions often requires that some form of soil improvement be performed to allow for their use in various civil engineering applications, such as for road base or subbase construction. One of the most commonly utilized stabilization techniques for laterite soils is the application of additives that chemically react with the minerals that are present in soil to enhance its overall strength; effective soil stabilization can allow for the use of site-specific soils, and can consequently result in significant cost savings for a given project. With an increasing focus on the use of more environmentally friendly and sustainable materials in the built and natural environments, there is an emerging interest in eco-friendly additives that are an alternative to traditional chemical stabilizers. The current study examines the viability of xanthan gum as an environmentally friendly stabilizer that can improve the engineering properties of tropical residual laterite soil. Unconfined compressive strength (UCS) tests, standard direct shear tests, Brunauer, Emmett, and Teller (N₂-BET) surface area analysis tests and field emission scanning electron microscopy (FESEM) tests were used to investigate the effectiveness of xanthan gum for stabilization of a tropical laterite soil. The UCS test results showed that addition of 1.5% xanthan gum by weight yielded optimum stabilization, increasing the unconfined compressive strength of the laterite soil noticeably. Similarly, direct shear testing of 1.5% xanthan gum stabilized laterite specimens showed increasing Mohr–Coulomb shear strength parameters with increases in curing time. From the FESEM results, it was observed that the stabilization process modified the pore-network morphology of the laterite soil, while also forming new white layers on the surface of the clay particles. Analysis of the test results indicated that xanthan gum stabilization was effective for use on a tropical residual laterite soil, providing an eco-friendly and sustainable alternative to traditional soil stabilization additives such as cement or lime.