This research was conducted to bring out the appropriate level of heavy metal contamination in soil at the site of Buriganga river bank near the Hazaribagh tannery area and the normal agricultural area to evaluate heavy metal contamination in soil due to untreated tannery effluents. AAS flame method was used to determine the concentration of Chromium (Cr), lead (Pb), Cadmium (Cd), Zinc (Zn) in several depths of the soil. Results showed that, the heavy metal concentration in soil at the site of Buriganga river bank in the tannery vicinity and normal agricultural area significantly varies, such as Cr varies (561.71 -31.23) mg/kg, Zn varies (158.23 -73.5), Pb varies (70.58 -24) and Cd varies (2.25 -0.71) mg/kg in the river bank as well as in the normal agricultural area Cr varies ) and Cd varies (1.30 -0.64) mg/kg. The study indicated that heavy metals concentration was found to be significantly higher in river bank soils than in the normal agricultural area. This metal concentration in soil is responsible for the promotion of toxicity in agricultural products. Therefore, the human health and environment are affected by these areas.

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There has been much recent work on developing models of non-reactive solute migration in saturated stratified porous media. Almost all experimental results against which the models have been tested have been obtained using artificial media. The aim of the present study is to test the models against data from naturally stratified media. In this paper we report the results of the experiments carried out on samples of laminated, intact, saturated Triassic sandstone from the UK. Column experiments were performed at steady flow rates using samples with flow either parallel or perpendicular to the lamination. For flow parallel to the lamination, the breakthrough curves were asymmetrical. They were generally characterized by early breakthrough and tailing. Asymmetry and tailing increased with increasing flow rate. Column experiments in which flow was interrupted showed the presence of physical non-equilibrium. For flow perpendicular to the lamination the breakthrough curves were symmetrical. Simultaneous use of bromide and amino-G-acid, conservative tracers having very different diffusion coefficients, demonstrated the significance of diffusion particularly when the flow is parallel to the lamination. Thinsection analysis, dye staining and positron emission projection imaging (PEPI) techniques were used to study the spatial variations in hydraulic properties in the samples. Thinsection analysis indicated that the thickness of individual layers, each of different porosity and grain size, varies from less than 1 mm to several millimetres and occasionally exceeds 1 cm. The dye and PEPI experiments also identified stratification of flow when the flow is parallel to the lamination, but in the latter case the most obvious stratification was at a larger scale than for the former. No preferential flow was found for samples with flow perpendicular to the lamination. It is concluded that the dominant process in solute migration in the sandstone samples is stratification that is, at least, at two scales, a process which will result in a fractionation where two solutes of different diffusion coefficient are present.

The study area is located in the central part of Bangladesh. The aims of this study were to explain the hydrogeological characteristics of aquifers and evaluate the groundwater potentiality. The borehole logs revealed three types of zones: upper aquitard (low permeability clays, silty clays & silts), upper aquifer (very fine sand to fine sand) and lower aquifer (medium to coarse sands and gravels). Both aquifer waters are mainly Ca-Mg-HCO3 type. Except arsenic (As), most of the ions of both aquifer waters are within the limit of drinking standard of WHO (2004) and Bangladesh (DoE, 1997). Arsenic concentrations of upper aquifer exceed both the WHO (10 µg/l) and Bangladesh standard (50 µg/l) and for lower aquifer exceed only WHO standard. Waters of both aquifers in north western and central part of the study area show high arsenic concentration due to lack of continuous impermeable layer between them as revealed from borelog data. Water quality index map also indicates that north western and central part is not suitable for groundwater development because of inferior quality. The average δ 18 O values for upper and lower aquifer waters are isotopically enriched compared to river water (10.08‰). Similar isotopic composition of upper (4.77‰) and lower aquifer waters (5.50‰) indicates both waters were mixed in the past and mixing may be continued in the future. The mixing may be preferentially from the upper aquifer to lower aquifer because of water abstraction, lack of impermeable layer and high permeability of the upper aquifer etc. Therefore, the potentiality of the lower aquifer may not be suitable for large-scale groundwater development project without any mitigation measure.