Coastal water pollution in two rivers of the Bengal delta

A thorough comprehension of relevant environmental parameters is a prerequisite to preventing coastal degradation and environmental balance in coastal zones. In this study, we correlate major physicochemical of two coastal rivers (Matla and Saptamukhi) in the Sunderban district, West Bengal. The parameters namely: pH, salinity, dissolved oxygen, suspended solids, nitrogen and phosphorus concentrations (inorganic and total) of these two rivers were studied in detail over the 90s decade. We hypothesized that both natural and anthropogenic activities during that time have contributed to the pollution and employed the above parameters to test our hypothesis. Our results reveal that the quality of waters in the rivers have been showed to be dependent on flood impacts, storm surge, eutrophication, domestic sewage, agricultural and industrial wastes. Thus, both natural and anthropogenic causes are the behind coastal pollution of river waters. We conclude that they have all contributed to pollution of these rivers in various ways and we calculate the differential effects of these parameters on coastal pollution.     

Delineation of groundwater protection zones by the backward particle tracking method: theoretical background and GIS-based stochastic analysis

The backward particle tracking method, an effective and powerful tool that can be used to delineate groundwater protection zones, is presented. The theoretical background and insights on the applicability of this method are provided. Moreover, the present work enriches the backward particle tracking method with an uncertainty analysis concerning the porosity values, applying a Monte Carlo (MC) approach, coupled with the use of geographical information systems (GIS). As an application example, a wellfield in the Komotini area, Greece, is investigated. The present study may serve as a potential guideline for wellfield delineation, particularly in areas like Greece where lack of data related to the hydrogeological system is often a problem.     

Physical Meaning of Stress Difference for Fault-Slip Analysis

Recent stress tensor inversion methods for fault-slip analysis are used to distinguish between multiple stress states to elucidate spatiotemporal change of the earth’s crustal tectonics. An estimator named the stress difference has been a practicable tool to measure the difference between stress solutions of inversion analysis. This measure corresponds to the expected difference in shear stress direction on a randomly oriented fault plane, which is, however, an approximation including several degrees of deviation. This study investigated the formula of stress difference and found the exact physical meaning, specifically the expected difference in shear stress vector which carries information on magnitude as well as direction. The present discovery is based on the analytical proportionality between the second invariant of stress tensor and the root mean square magnitude of shear stress for all orientation of fault planes. The meaningless difference in non-dimensional shear stress magnitude was found to be incorporated into the value of stress difference. This fact is not convenient for fault-slip analysis dealing only with orientations.     

The study of hydrodynamic behaviour of a complex karst system under low-flow conditions using natural and artificial tracers (the catchment of the Unica River,SW Slovenia)

In this study a multi-tracer test with fluorescent tracers was combined with time series analyses of natural tracers to characterize the dynamics of the solute transport through different recharge pathways and to study hydraulic behaviour of a binary karst system under low-flow conditions. Fluorescent tracer testing included the introduction of uranine, amidorhodamine G, or naphthionate at three injection points. Sampling and monitoring took place at two karst springs (Malenščica, Unica) and at two underground rivers (Pivka, Rak) recharging the Unica River at the Polje of Planina, SW Slovenia. Other monitored parameters included precipitation, spring or underground river discharge, water temperature, and electrical conductivity. Water samples were collected and analyzed for total organic carbon, Mg²⁺, SO₄ ²⁻, and NO₃ ⁻ in the laboratory. In the study area, results of the tracer test suggest that contaminant transport in karst may be retarded for several weeks during low-flow conditions followed by increases in contaminant concentrations after subsequent rainfall events. Based on interpretation of tracer concentration breakthrough curves, low apparent dominant flow velocities (i.e., between 5.8 and 22.8 m/h through the well developed karst conduits, and 3.6 m/h through the prevailing vadose zone with a dominant influence of a diffuse recharge) were obtained. Together with analyses of hydro-chemographs the artificial tracing identified different origins of water recharging the studied aquifer. During prolonged low-water conditions the Malenščica spring is mainly recharged from the karst aquifer and the Unica spring by the sinking Pivka River. After more intensive rainfall events allogenic recharge from Cerknica prevails in the Malenščica spring, while the Unica spring drains mainly the allogenic water from the Pivka Valley. These findings of alternating hydraulic connections and drainage areas due to respective hydrological conditions are important and should be considered when monitoring water quality, implementing groundwater protection measures, and optimizing future water exploitation.     

Variation in DOC and trace metal concentration along the heavily urbanized basin in Kathmandu Valley,Nepal

Water samples were analyzed for DOC and trace metals from Bagmati River within Kathmandu valley, Nepal, to understand the variation trends of DOC and trace metals and their relationship along the drainage network. The variability in organic matter and wastewater input within the Bagmati drainage basin appeared to control DOC and most of the trace metal concentration. The large input of organic matter and wastewater creates anoxic condition by consuming dissolved oxygen and releasing higher concentrations of DOC, trace elements such as nickel, arsenic, barium, cadmium, and copper with downstream distance. Concentrations of DOC and trace metals like barium and zinc showed strong relationships with human population density and suggest that human activities have strong control on these parameters along the drainage network. The DOC and most of the trace metal concentration increased with downstream distance and appeared to be directly associated with human activities. The variation trends of most of the trace metals appeared to be the same; however, concentration varied widely. Inputs of organic matter and wastewater due to human activities appeared directly to be associated for the variation of DOC and trace metals along the Bagmati drainage network within Kathmandu valley.     

Stabilization of Expansive Clays Using Granulated Blast Furnace Slag (GBFS) and GBFS-Cement

Expansive clays undergo swelling when subjected to water. This can cause damage, especially to light weight structures, water conveyance canals, lined reservoirs, highways, and airport runways unless appropriate measures are taken. In this study, granulated blast furnace slag (GBFS) and GBFS-cement (GBFSC) were utilized to overcome or to limit the expansion of an artificially prepared expansive soil sample (sample A). GBFS and GBFSC were added to sample A in proportions of 5–25% by weight. The effects of these stabilizers on grain size distribution, Atterberg limits, swelling percentage and rate of swell of soil samples were determined. GBFS and GBFSC were shown to successfully decreasing the total amount of swell while increasing the rate of swell.     

Low-mature gases and their resource potentiality

In the 80’s of last century, based on the advances in natural gas exploration practice, the concepts of bio-thermocatalytic transitional-zone gas and early thermogenetic gas were proposed, and the lower limit Ro values for the formation and accumulation of thermogenetic natural gases of industrial importance have been extended to 0.3%–0.4%. In accordance with the two-stage model established on the basis of carbon isotope fractionation involved in the formation of coal-type natural gases, the upper limit Ro ...     

Magmatic history and geophysical signature of a post-collisional intrusive center emplaced near a crustal-scale shear zone: the Plechý granite pluton (Moldanubian batholith,Bohemian Massif)

The Plechy pluton, southwestern Bohemian Massif, represents a late-Variscan, complexly zoned intrusive center emplaced near the crustal-scale Pfahl shear zone; the pluton thus provides an opportunity to examine the interplay among successive emplacement of large magma batches, magmatic fabric acquisition, and the late-Variscan stress field associated with strike-slip shearing. The magmatic history of the pluton started with the emplacement of the porphyritic Plechy and Haidmühler granites. Based on gravity and structural data, we interpret that the Plechy and Haidmühler granites were emplaced as a deeply rooted, ∼NE–SW elongated body; its gross shape and internal fabric (steep ∼NE–SW magmatic foliation) may have been controlled by the late-Variscan stress field. The steep magmatic foliation changes into flat-lying foliation (particularly recorded by AMS) presumably as a result of divergent flow. Magnetic lineations correspond to a sub-horizontal ∼NE–SW finite stretch associated with the divergent flow. Subsequently, the Třístoličník granite, characterized by steep margin-parallel magmatic foliation, was emplaced as a crescent-shaped body in the central part of the pluton. The otherwise inward-younging intrusive sequence was completed by the emplacement of the outermost and the most evolved garnet-bearing granite (the Marginal granite) along the southeastern margin of the pluton. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Maximum entropy method: an unconventional approach to explore observables related to the electron density in phengites

The maximum entropy method (MEM) is used here to get an insight into the electron density [ρ(r)] of phengites 2M ₁ and 3T, paying special attention to the M1-formally empty site and charge distribution. Room temperature single crystal X-ray diffraction data have been used as experimental input for MEM. The results obtained by MEM have been compared with those from conventional structure refinement which, in turn, has provided the prior-electron density to start the entropy maximization process. MEM reveals a comparatively non-committal approach, able to produce information related to the M1-site fractional occupancy, and yields results consistent with those from the difference Fourier synthesis, but free of the uncertainties due to the abrupt truncation of the series. The charge distribution is investigated by means of the notion of ‘‘site basin’’, i.e., those site-centered volumes delimited by a surface such as ∇ρ·n = 0. In particular, we observe: (1) the overall partitioning of the basin total charge between cation and anion sites, and the interlayer site charge seems to depend on sample composition, and (2) the apical-oxygen plane total basin charge and hydroxyl basin charge are presumably related to the polytype. The MEM-determined electron density does not allow full exploration of the critical points for very complex structures as micas, insofar as conventional room temperature experimental diffraction data are used.     

Economic relationships among southern African states

It is widely held that the large majority of African countries are too small in terms of population and purchasing power to allow meaningful and rapid economic development to take place within the constraints of their domestic economies. Sub-regional groupings of states are called for in order to overcome the drawbacks of small size. Many attempt at establishing larger economic unions in Africa have failed. Particular interest therefore attaches to the southern African sub-region where South Africa, as the only industrial power south of the Sahara, functions as a powerhouse for neighbouring as well as more distant economies. The article provides a factual sketch of existing economic ties (infrastructure, trade, labour, tourism, finance and technology). Attention is paid to South Africa's efforts to create a constellation of states, and also to to the counter-measures of nine neighbouring states.