Semi-analytical solutions of a contaminant transport equation with nonlinear sorption in 1D

A new method to determine semi-analytical solutions of one-dimensional contaminant transport problem with nonlinear sorption is described. This method is based on operator splitting approach where the convective transport is solved exactly and the diffusive transport by finite volume method. The exact solutions for all sorption isotherms of Freundlich and Langmuir type are presented for the case of piecewise constant initial profile and zero diffusion. Very precise numerical results for transport with small diffusion can be obtained even for larger time steps (e.g., when the Courant-Friedrichs-Lewy (CFL) condition failed).     

Land subsidence and caprock dolines caused by subsurface gypsum dissolution and the effect of subsidence on the fluvial system in the Upper Tigris Basin (between Bismil–Batman, Turkey)

Karstification-based land subsidence was found in the Upper Tigris Basin with dimensions not seen anywhere else in Turkey. The area of land subsidence, where there are secondary and tertiary subsidence developments, reaches 140 km². Subsidence depth ranges between 40 and 70 m. The subsidence was formed as a result of subsurface gypsum dissolution in Lower Miocene formation. Although there are limestones together with gypsum and Eocene limestone below them in the area, a subsidence with such a large area is indicative of karstification in the gypsum. The stratigraphical cross-sections taken from the wells and the water analyses also verify this fact. The Lower Miocene gypsum, which shows confined aquifer features, was completely dissolved by the aggressive waters injected from the top and discharged through by Zellek Fault. This resulted in the development of subsidence and formation of caprock dolines on loosely textured Upper Miocene–Pliocene cover formations. The Tigris River runs through the subsidence area between Batman and Bismil. There are four terrace levels as T1 (40 m), T2 (30 m), T3 (10 m) and T4 (4–5 m) in the Tigris River valley. It was also found that there were some movements of the levels of the terraces in the valley by subsidence. The subsidence developed gradually throughout the Quaternary; however no terrace was formed purely because of subsidence.     

Anomalous optical variations in the grossular garnet from the Eden Mills,Belvidere Mountain (Vermont,USA)

The optical anomalies, and surface and lamellar textures of a birefringent grossular garnet crystal from the Eden Mills, Belvidere Mountain, Vermont, USA, have been investigated by optical polarizing microscope, electron-probe micro-analyzer, back-scattered electron imaging, infrared spectroscopy, and single-crystal X-ray diffractometer from the standpoint of crystal growth. This grossular shows one-to-one correlation between natural surface features and its internal textures under crossed polarizers. Electron-probe micro-analyzer (EPMA) gave average chemical composition in (110) thin section, of bright lamella {Ca_2.97Mn_0.06}_∑3.03 [Al_1.59Fe_0.37Ti_0.01]_∑1.97(Si_3.00)_∑3.00 (Gros_79.5And_18.9Sps_1.6) and of dark host {Ca_2.99Mn _0.06}_∑3.05 [Al_1.73Fe_0.26 Ti_0.01]_∑2.00(Si_2.97OH_0.03)_∑3.00 (Gros_85.4And₁₃Sps_1.6). The correspondence of surface features and the internal textures with spiral or pyramidal growth mechanism suggest that the internal textures of the Eden Mills grossular are formed during growth process. The optical vibrational orientations and the growth steps inclination along [001] and \( \left[\overset{-}{1}10\right] \) directions predict monoclinic symmetry. With X-ray diffractometer (XRD) method, pseudocubic parameters are a = 11.839(2) Å, b = 11.855(1) Å, and c = 11.868(2) Å with interaxial angles α = 90.00(1)°, β = 89.99(1)°, and γ = 90.02(2)° that show orthorhombic symmetry of this crystal. Lamellar texture of Al³⁺-rich host with Fe³⁺-rich lamella infers cation ordering at octahedral site of the garnet structure. IR data favors the non-cubic orientation of [(OH) ₄] at tetrahedral position in this grossular structure.     

Uranium (U) concentration and its genetic significance in the phosphorites of the Paleoproterozoic Bijawar Group of the Lalitpur district,Uttar Pradesh,India

The paper presents the uranium (U) concentration and distribution pattern in the Paleoproterozoic phosphorites of Lalitpur district of Uttar Pradesh. The study of thin sections, SEM and XRD reveal that apatite is the essential phosphate mineral while quartz and feldspars are the dominant gangue in the phosphorites of the investigated area. The collophane is observed to be mostly oolitic in form and microspherulitic in texture. The major element geochemistry indicated that the phosphorite samples are rich in P₂O₅, CaO, SiO₂ and Fe₂O₃ whereas depletion of MgO, MnO, K₂O and Al₂O₃ was observed. The CaO/P₂O₅ ratio ranges from 1.13 to 1.46 which is slightly lower than that of cations and anions substituted francolite (1.621) and close to that of carbonate-fluorapatite (1.318). The trace element geochemistry indicates that the phosphorites of Lalitpur have the significant range of U concentration (1.67 to 129.67 μg/g) which is more than that of Th (0.69 to 0.09 μg/g) among the analysed trace elements in the phosphorite samples of the area. The positive correlation of U with P₂O₅, CaO and U/P₂O₅ indicates a close association of U with phosphate minerals like collophane (apatite), whereas negative correlation of U with SiO₂ and Fe₂O₃ may be due to mutual replacement. The antipathetic relationship of U with Ni may be an indication of high oxidizing conditions, whereas sympathetic relationship of U with K₂O points towards higher alkaline conditions of the basin of deposition during phosphatization. The variable concentration of U and its relationship with significant major and trace elements in most of the phosphorite samples lead one to believe that the deposition of these phosphorites might have taken place in highly alkaline medium during fairly oxidizing to weakly reducing environmental conditions of geosynclinal basin.     

Yield Forecasting of Spring Maize Using Remote Sensing and Crop Modeling in Faisalabad-Punjab Pakistan

Real time, accurate and reliable estimation of maize yield is valuable to policy makers in decision making. The current study was planned for yield estimation of spring maize using remote sensing and crop modeling. In crop modeling, the CERES-Maize model was calibrated and evaluated with the field experiment data and after calibration and evaluation, this model was used to forecast maize yield. A Field survey of 64 farm was also conducted in Faisalabad to collect data on initial field conditions and crop management data. These data were used to forecast maize yield using crop model at farmers’ field. While in remote sensing, peak season Landsat 8 images were classified for landcover classification using machine learning algorithm. After classification, time series normalized difference vegetation index (NDVI) and land surface temperature (LST) of the surveyed 64 farms were calculated. Principle component analysis were run to correlate the indicators with maize yield. The selected LSTs and NDVIs were used to develop yield forecasting equations using least absolute shrinkage and selection operator (LASSO) regression. Calibrated and evaluated results of CERES-Maize showed the mean absolute % error (MAPE) of 0.35–6.71% for all recorded variables. In remote sensing all machine learning algorithms showed the accuracy greater the 90%, however support vector machine (SVM-radial basis) showed the higher accuracy of 97%, that was used for classification of maize area. The accuracy of area estimated through SVM-radial basis was 91%, when validated with crop reporting service. Yield forecasting results of crop model were precise with RMSE of 255 kg ha^?1, while remote sensing showed the RMSE of 397 kg ha^?1. Overall strength of relationship between estimated and actual grain yields were good with R² of 0.94 in both techniques. For regional yield forecasting remote sensing could be used due greater advantages of less input dataset and if focus is to assess specific stress, and interaction of plant genetics to soil and environmental conditions than crop model is very useful tool.     

Chemical evolution of the Mt. Hekla,Iceland, groundwaters: A natural analogue for CO2 sequestration in basaltic rocks

A detailed study of the chemical composition of the groundwater surrounding the Mt. Hekla volcano in south Iceland was performed to assess fluid evolution and toxic metal mobility during CO₂-rich fluid basalt interaction. These fluids provide a natural analogue for evaluating the consequences of CO₂ sequestration in basalt. The concentration of dissolved inorganic C in these groundwaters decreases from 3.88 to 0.746 mmol/kg with increasing basalt dissolution while the pH increases from 6.9 to 9.2. This observation provides direct evidence of the potential for basalt dissolution to sequester CO₂. Reaction path calculations suggest that dolomite and calcite precipitation is largely responsible for this drop in groundwater dissolved C concentration. The concentrations of toxic metal(loid)s in the waters are low, for example the maximum measured concentrations of Cd, As and Pb were 0.09, 22.8 and 0.06 nmol/kg, respectively. Reaction path modelling indicates that although many toxic metals may be initially liberated by the dissolution of basalt by acidic CO₂-rich solutions, these metals are reincorporated into solid phases as the groundwaters are neutralized by continued basalt dissolution. The identity of the secondary toxic metal bearing phases depends on the metal. For example, calculations suggest that Sr and Ba are incorporated into carbonates, while Pb, Zn and Cd are incorporated into Fe (oxy)hydroxide phases.     

Concentration of selected radionuclides in seawater from Kuwait

No baseline existed for the radionuclides in Kuwait territorial water. With changing trend in the region to embrace nuclear energy, the baseline study is imperative to create a reference and to record the influence-functioning of upcoming power plants. The first one in Bushehr, Iran is ready to start and several more are likely to come-up in UAE, Saudi Arabia and Kuwait. The present baseline concentration of the four considered radionuclide's show low concentration of tritium, polonium, strontium and cesium; their concentration is comparable to most oceanic waters.     

Hydrochemical characterisation of ground and surface water at Dörtyol/Hatay/Turkey

The degradation of ground water quality due to human activities is a widespread environmental problem. Furthermore, coastal aquifers are threatened by sea water intrusion as a result of increasing water exploitation. The investigation area near Dörtyol is located at the Mediterranean coast, southern Turkey, and dominated by agricultural land use. Drinking, domestic and agricultural purposes require different amounts of uncontaminated water. In this study the hydrogeological characteristics of the coastal plain were investigated. Discharge and ground water level measurements as well as geological investigations were undertaken in field in addition to anion and cation analyses of ground and surface water. The results show geological and anthropogenic influence on ground and surface water composition. In spite of a large number of wells in the coastal area sea water intrusion was not detected. With the goal of devising sustainable water use regulations, more emphasis and research needs to be directed to the long-term observation of ground and surface water quality as well as the detailed investigation of hydraulic characteristics of the local aquifer.