Cadmium (Cd) concentration in wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis>) grown in Cd-spiked soil varies with the doses and biochar feedstock

Biochar is considered a promising amendment for the reduction of metal concentration in plants; however, the effects of biochar in terms of dose and feedstock on metal uptake by plants remain widely unclear. In the current study, three individual biochars were prepared at 450 °C from different feedstocks (wheat straw, sukh chain (Pongamia pinnata), and cotton sticks). The main aim was to evaluate their ability to remediate cadmium (Cd)-spiked soil in terms of growth response and Cd uptake by wheat (Triticum aestivum) tissues. Biochars were separately applied at 0, 1, and 2% (w/w) in Cd-spiked soil and wheat was grown until maturity in pots and then morphological and physiological parameters and Cd concentrations in grains, roots, and shoots were determined. The post-harvest soil was analyzed for extractable Cd concentrations. Plants grown in Cd-spiked soil treated with biochars had higher seed germination, lengths of roots, shoots, and spikes, grains per spike and leaf relative water contents, chlorophyll contents, and dry weight of roots, shoots, and grains as compared to the untreated control. Biochar treatments significantly decreased the Cd concentrations in shoots, roots, and grains as well as total Cd uptake by grains. Soil extractable Cd concentrations were significantly decreased with biochar treatments. The application of 2.0% wheat straw biochar was the most efficient treatment in increasing grain yield and decreasing Cd in grains as well as soil extractable Cd than the other two biochars and doses applied.     

The Genesis,Classification, Problems and Prospects of Microbial Carbonates:Implications from the Cambrian Carbonate of North China Platform

Currently, sedimentologists focus on the challenging issue of microbial carbonates, which are regarded as "one of the sedimentary rocks most difficult to study", having complicated sedimentary fabric. Their characteristic features closely related to microbial activity, distributed over a long period of geological time, and formed in diversified sedimentary environments. The main research concentrations are the calcified microbial mats and biofilms in geological records as the products of lithification and diagenesis. Starting from the origin, this paper systematically reviewed and explained the processes dwelling within two types of microbial communities, the thinner biofilm and the thicker microbial mat, which enabled them to convert into microbial carbonates through biomineralization and lithification. This study proposed that the existence of multiple microbial mats was another important cause for the diversification and complexity of microbial carbonates in addition to its complex depositional process. Moreover, the sedimentary characteristics and classification of different types of microbial carbonates were reviewed, exemplifying the Cambrian microbial carbonates in the North China Platform. These microbial carbonates are suggested to be placed under "bindstone" after Embry and Kloven, which can be further divided into 5 types, stromatolites, thrombolites, oncolites, laminites and leiolites. Dendrolite is not categorized as a separate class, instead attributed to thrombolites. The microbial carbonates may possess good source rock potential because of the enriched organic content, and may also serve as hydrocarbon reservoirs because of certain microbial textures and fabrics leading to significant porosity and permeability. Because of their biomineralization processes related to microbial activity, the microbial carbonates are not only an important window to understand the evolution of the earth's surface environment, but also capable of forming large-scale reservoirs, and their scientific and economic values are self-evident.     

Cd,Ni, and Pb distribution and pollution assessment in roadside dust from Baghdad City and Western Iraqi Desert

Roadside dust samples were collected from selected areas near the fuel stations in Karkh District of Baghdad City, the capital of Iraq, as well as both sides of the highway between Ramadi and Rutba. In order to assess the probable pollution level of heavy metals (Cd, Ni, and Pb) in the study areas, they were determined in the roadside dust using an atomic absorption spectrophotometer. The extent of traffic contribution to roadside dust was assessed by comparing the metal concentrations in roadside dust to those of Upper Continental Crust background considering a Cd background of 0.098 mg/km, Ni background of 44 mg/km, and Pb background of 16 mg/km using geo-accumulation index (I _geo), contamination factor (CF), and pollution load index (PLI). The roadside dust contains relatively elevated levels of heavy metals. The average concentration of Cd, Ni, and Pb in Baghdad is 0.17, 25.5, and 14.8 mg/kg; in the north of the highway is 0.14, 23.4, and 14.7 mg/kg; and in the south of the highway is 0.2, 27.4, and 15.6 mg/km. The higher averages of these metals were recorded in the south of the highway. The study areas are impacted with considerable quantity of metals. The distribution pattern of the concentrations of metals was essentially affected by exhausted gases emitted from transportation automobile where the direction of the prevailing wind played a major role in the transport of the pollutants, causing an increase in metal concentrations towards the south side of the highway.     

Distribution of gold in different size fractions of stream sediments as a guide to bedrock gold mineralisation along the Shyok Suture Zone and adjacent areas of the Kohistan Island Arc,Pakistan

Arabian Journal of Geosciences - This paper describes a new exploration methodology using stream sediments in remote and glaciated regions of northern Pakistan. Gold concentrations in 268 samples...     

Impact of uncertainty in remote sensing DEMs on topographic amplification of seismic response and Vs 30

Arabian Journal of Geosciences - Impact of topography on spatial variation of seismic response is well-observed synthetically, experimentally, and visually during seismic events. Numerical and...     

Location-allocation modeling for emergency evacuation planning with GIS and remote sensing: A case study of Northeast Bangladesh

This work developed models to identify optimal spatial distribution of emergency evacuation centers(EECs) such as schools, colleges, hospitals, and fire stations to improve flood emergency planning in the Sylhet region of northeastern Bangladesh.The use of location-allocation models(LAMs) for evacuation in regard to flood victims is essential to minimize disaster risk.In the first step, flood susceptibility maps were developed using machine learning models(MLMs), including: Levenberg–Marquardt back propagation(LM-BP) neural network and decision trees(DT) and multi-criteria decision making(MCDM) method.Performance of the MLMs and MCDM techniques were assessed considering the area under the receiver operating characteristic(AUROC) curve.Mathematical approaches in a geographic information system(GIS) for four well-known LAM problems affecting emergency rescue time are proposed: maximal covering location problem(MCLP), the maximize attendance(MA), p-median problem(PMP), and the location set covering problem(LSCP).The results showed that existing EECs were not optimally distributed, and that some areas were not adequately served by EECs(i.e., not all demand points could be reached within a 60-min travel time).We concluded that the proposed models can be used to improve planning of the distribution of EECs, and that application of the models could contribute to reducing human casualties, property losses, and improve emergency operation.     

The evolution of an electrical fittings industrial cluster in Pakistan

GeoJournal - This study provides an evolution process of electrical fittings industrial cluster in Pakistan by using two rounds of survey dataset (2008 and 2017) taken from the electrical fittings...     

Comparative study of flash flood in ungauged watershed with special emphasizing on rough set theory for handling the missing hydrological values

Natural Hazards - Prediction of the flash floods in ungauged or poorly gauging watershed is one of the challenging tasks in the field of hydrology and needs implication of advanced techniques to...     

Stability Analysis of Landslide near Dewal Village along Murree-Muzaffarabad Road,Pakistan

This study presents a detailed geological and geotechnical analysis of Dewal landslide along Murree-Muzaffarabad road, Pakistan. The study area is situated in a tectonically active region of the earth where mass movements like rock fall, rockslides and slumps cause adverse economic loss through disruption of travelling on roads. The study has the main focus on factors responsible for its instability together with stability analysis using limit equilibrium method by use of computer program Slide (version 5.0). The input parameters of rock mass was evaluated by field investigations and laboratory testing. To analyze the net deposit and net slide mass of the landslide area, multi-date point’s data of 2008 and 2012 of the slide area was obtained and their digital elevation models were generated by using Inverse distance weighting (IDW) technique in ArcGIS 9.3. The study has concluded that the present slope instability is the function of a specific deformation pattern in the rock units (leading towards the possibility of a shear plane under the slid mass), surface and subsurface drainage and the engineering behavior of the overburden and underlying rock units. This study recommends several protection parameters for landslide and suggests that detailed investigation of Dewal landslide is required for long term stability.     

Linear regression models for estimating true subsurface resistivity from apparent resistivity data

Simple linear regression (SLR) models for rapid estimation of true subsurface resistivity from apparent resistivity measurements are developed and assessed in this study. The objective is to minimize the processing time and computer memory required to carry out inversion with conventional algorithms. The arrays considered are Wenner, Wenner–Schlumberger and dipole–dipole. The parameters investigated are apparent resistivity (\(\rho _a \)) and true resistivity (\(\rho _t\)) as independent and dependent variables, respectively. For the fact that subsurface resistivity is nonlinear, the datasets were first transformed into logarithmic scale to satisfy the basic regression assumptions. Three models, one each for the three array types, are thus developed based on simple linear relationships between the dependent and independent variables. The generated SLR coefficients were used to estimate \(\rho _t\) for different \(\rho _a\) datasets for validation. Accuracy of the models was assessed using coefficient of determination (\(R^{2})\), F-test, standard error (SE) and weighted mean absolute percentage error (wMAPE). The model calibration \(R^{2}\) and F-value are obtained as 0.75 and 2286, 0.63 and 1097, and 0.47 and 446 for the Wenner, Wenner–Schlumberger and dipole–dipole array models, respectively. The SE for calibration and validation are obtained as 0.12 and 0.13, 0.16 and 0.25, and 0.21 and 0.24 for the Wenner, Wenner–Schlumberger and dipole–dipole array models, respectively. Similarly, the wMAPE for calibration and validation are estimated as 3.27 and 3.49%, 3.88 and 5.72%, and 5.35 and 6.07% for the three array models, respectively. When compared with standard constraint least-squares (SCLS) inversion and Incomplete Gauss–Newton (IGN) algorithms, the SLR models were found to reduce about 80–96.5% of the processing time and memory space required to carry out the inversion with the SCLS algorithm. It is concluded that the SLR models can rapidly estimate \(\rho _t\) for the various arrays accurately.