Landfills imbued with heavy elements are major threats to the environment. To assess anthropogenic enrichment, soil, leachate and groundwater samples were collected from active landfills in Lagos and analysed for some heavy elements. The geology of the sampled areas is essentially that of the Oligocene to Pleistocene Coastal Plain Sands except for those of Epe and Badagry which are Recent Deposits. The groundwater showed a range of values (in mg/l) of: Zn, 0-0.08; Fe, 0.009-1.104; Ni, 0.007-0.039; Cd, 0.013-0.062; Hg, 0.00008-0.00384; Pb, 0.004-0.63; Cr, 0.017-0.075; Mn, 0.01-0.043; As, 0-0.053. From the results, some of the boreholes in Olusosun, Soluos, and the hand-dug well water in Ewu-Epe are unfit for drinking. In soils, concentrations were highest at the top and lowest at base of sampling. Generally, the concentrations of most of the elements decreased with increased distance and/or depth from the landfill soils. These suggest that the landfills contribute significantly to the level of these elements in these environments and imply significant attenuation with depth possibly due to adsorption and/or precipitation. The elevated levels of cadmium and arsenic do not support their use as compost for food cultivation. Also, the presence of arsenic above prescribed limits in the Epe leachate is a major concern because the lithology is sandy, and has a reported depth of about 3 m to the unconfined aquifer that adjoins the Epe Lagoon.
The present paper discusses with the problem of groundwater given by Boussinesq’s equation infiltration phenomenon in unsaturated porous media. The governing nonlinear partial differential equation is solved using optimal homotopy analysis method. The solution gives a height of free surface of infiltrated water table in unsaturated homogeneous porous media (soil) by using appropriate initial guess value of the solution. The numerical as well as graphical representation of the solution is given by Mathematica coding.
Temperature is one of the indicative factors of climate change which is one of the very important issues discussed in the recent two decades. The present research aimed at studying temporal and seasonal variation in temperature over North-eastern Nigeria, during the period 1981–2010. Trends in annual and seasonal temperature series were analyzed using Mann-Kendall test. The analysis revealed that temperature ranged between 20.2 - 31.8°C among all the locations, and over months and years. Temperature was significantly higher (P<0.01) in April compare to all the other months. The trends, both annual and seasonal, showed increasing tendency in temperature during the period 1981-2010. There was significant increase (positive trend) in temperature in all studied locations (less Taraba where trend was negative), indicating Nigeria is experiencing a rise in air surface temperature too. Since most of the Nigerian population is dependent on economic activities that are temperature sensitive, findings here implicate Nigeria is also one of the susceptible to the attendant consequences of global warming. Thus, the models developed in this study could assist the prediction of temperatures over the locations it covered.
Groundwater quality prospective zones of Tindivanam Taluk, Tamil Nadu were investigated and delineated by an integrated approach of remote sensing and geographical information system (gis). Various thematic maps like geology, geomorphology, lineament, drainage, land use/land cover and soil were prepared for the study area. The attribute information pertaining to water quality such as TDS, pH, TH, CR, Cl, have been plotted as point attributes (locations wells) for constructing contours. The selected attributes are based on the purposes of drinking (TDS), domestic (TH), industrial (CR) and agricultural/drinking (CL). The pre and post-monsoon water quality spatial scores are added and the highest positive score is considered as the resulting permissible parameters. The integration of TDS and TH have been done using the command union to obtain the map union1, and CR and Cl integrated to produce union 2 map. By integrating union 1 and union 2, union 3 has been produced, that is the final output map of overlay analysis. The final map is the final output map of overlay analysis. The final map has been categorized into three zones, namely good, tolerate and poor. From the final integrated map, it is inferred that freshwater exists in the north, northeastern and southern part of the study area (144.59 sqkm). The tolerate quality water occupies about (300.74 sqkm) and the poor quality water occupied by 154.89 sqkm.
This article outlines the prospect of natural gas hydrate in India, its identification, resource estimation and production technologies, and vital challenges associated with the viable production of natural gas from gas hydrates. It contains a brief review of petro-physical and chemical properties of gas hydrate, geological conditions, formation processes, morphology and accumulation of gas hydrate, geophysical, geochemical and microbiological indicators of gas hydrate accumulation, potential locales of gas hydrate, role of geophysical as well as well logging techniques for prospect investigation, conventional production technologies and theirs limitations, production scenario and the environmental issues related with commercial production of gas hydrate in India. The seismic studies for investigation of gas hydrate in Mahanadi and Andaman deepwater basins are depicted to exemplify the scenario of gas hydrate in India. Analysis of seismic data (Bottom simulating reflector (BSR), Coherency inversion and Amplitude-versus-offset (AVO) studies) in combination with geological preconditions (such as high rate of sedimentation, adequate depth and temperature coinciding with the BSR) indicate a large area of the order of 250 km2 in the central part of the basin as a probable gas hydrate accumulation area in Mahanadi deepwater basin. The analysis of AVO anomaly of BSR and seismic signatures of the study area in Andaman deep water basin reveal a pool of free gas beneath the hydrate layer which has been corroborated by drilling results of a well in the area.