Potential use of organic waste substances as an ecological technique to reduce pesticide ground water contamination

The heavy use of pesticides in agriculture has meant that the fate due to their movement after their application continue to be a real problem for the environment. In this work, a viable eco-remediation technique based on the use of natural organic substances (NOS) that characterize the Mediterranean region is proposed to demonstrate the efficiency of endosulfan sulphate removal from water. Experimental results showed that the pH of pesticide solutions and temperature negatively affect the adsorption process. According to adsorption kinetic data, 5 h were considered as the equilibrium time for realizing adsorption isotherm. The Freundlich isotherm model describes better the adsorption process of endosulfan sulphate on NOS tested. The Freundlich constant K_f depended mainly on the nature of each adsorbent and ranged from 5.56 for straw to 13.54 for date stones. The adsorption tests gave very satisfying results and point to the possible application of these supports as an ecological remediation technique to reduce pesticide contamination of aquatic ecosystems.     

Pesticides and lipids occurrence in Tangier agricultural soil (northern Morocco)

This study evaluates pesticide occurrence in Tangier agricultural soil (northern Morocco). Soil samples were measured for alpha endosulfan, beta endosulfan, endosulfan sulfate, alpha HCH, beta HCH, gamma HCH, aldrin, dieldrin, endrin, o,p′ DDT, p,p′ DDD, p,p′ DDE and p,p′ DDT. The analyses were performed by gas chromatography coupled with mass spectrometry (GC/MS). Endosulfan isomers (alpha and beta) and endosulfan sulfate were detected in soil samples, in which the beta isomer showed the highest concentrations. Some DDT metabolites (o,p′ DDT and p,p′ DDE) and alpha HCH were also detected in the analyzed soil. The lipid fraction of the soil samples was extracted by accelerated solvent extraction and fractionated using chromatographic techniques. The principal biomarkers obtained were alcohols, esters, ketones, aldehydes, fatty acids and hydrocarbons. Lipid biomarkers were characterized to determine soil organic matter sources. Experimental results showed that the organic matter was mainly of plant origin, although the bacterial contribution was significant.     

Geochemical characterization of the salinity of irrigated soils in arid regions (Biskra,SE Algeria)

Acta Geochimica - The agriculture in Biskra, southeastern Algeria, is based on traditional practices and characterized by small irrigated fields. In the last decades, the increasing demand in water...     

Gravity contributions to the understanding of salt tectonics from the Jebel Cheid area (dome zone, Northern Tunisia)

Detailed gravity measurements integrated with geological data were computed to constrain the mechanisms that were active during the emplacement of the Triassic evaporite-bearing folds of Jebel Cheid from the salt-dome zone in the Atlassic region. The gravity analysis consists in mapping the contrasting gravity responses: complete Bouguer anomaly, residual anomaly and derivative maps; the main results display a positive amplitude gravity anomaly as the response of Triassic evaporite bodies and important NE–SW-trending features at the boundaries between the Triassic outcrops and their enveloping strata. In contrast with gravity calculations of a salt dome structure usually resulting in negative gravity anomaly models, the Jebel Cheid clearly expresses a positive gravity anomaly; furthermore, this result is supported by synthetic gravity interpretation.     

A Modular Support Vector Machine for Active Learning of Urban Remote Sensing Images Classification in Algeria

In this work, we present a new strategy of active learning, based on a modular version of support vector machine (MSVM) applied to urban remote sensing images in Algeria. In general, the training set is highly imbalanced, which gives more complex models; this difficulty is solved by dividing the problem at hand into a set of sub-problems, where each sub-model could be simpler to solve. The support vector machine is introduced to solve the problem of classification based on image remote sensing data related to atmospheric conditions and illumination reflectance. The aim of the proposed method is to improve the accuracy in order to understand the correlated elements of urban structures (the site, the built, the parcels, the network, the space), to generate the final classification result. In particular, we propose a new method based on the modular support vector machine (MSVM) adopted to active learning method, using three different clustering methods (i) k-means, (ii) fuzzy c-means (FCM), and (iii) Gustafson–Kessel (GKclust). Experimental results obtained on two QuickBird multispectral images of Sétif and Batna cities in the eastern of Algeria confirm the capabilities of the proposed methods based on the ensemble of model trained with different task decomposition compared to a traditional model using active learning. This method improves each class presents a main register in urban structure tissues.     

Prediction of future situation of land use/cover change and modeling sensitivity to pollution in Edku Lake,Egypt based on geospatial analyses

GeoJournal - Assessing land use/cover (LULC) change in coastal lakes is an essential process for sustainable development. Edku Lake is one of the most important lakes in the northern part of Nile...     

Deformed dike swarms as an implication of transpression deformation in Western Arabian shield,Wadi Fatima,Saudi Arabia

Utilization of satellite images and field observations of dike swarms in pre-Fatima basement show that these dikes are older than the overlaying Fatima Formation. Dikes digitization and orientation analysis on satellite images show that the prevailing trend of the dikes is ENE-WSW. The granitic rocks of pre-Fatima basement and its hosted dikes expose evidences of completely a different deformation regime from the overlaying Fatima Formation. These evidences include shearing, dextral shear indicators, isoclinal folds, deflection and rotation of crystals, mineral elongation, and mylonitic and gneissose textures. Strain analysis results of using Fry method on quartz and feldspar grains support the presence of deformation in these ENE-WSW dikes. These results gave a strain ratio of 2.1:1.3:1, which suggest an amount of 40% stretching in the ENE-WSW direction parallel to the dike walls, and an amount of 30% shortening in the NNW-SSE direction. Mesoscopic and microscopic scale structures confirm the existence of dextral ductile-brittle shearing followed the emplacement of the dikes and before the pure shear deformation that caused the thrusting and folding of Fatima Formation. This ductile-brittle deformation is correlated with the dextral transpression that formed the Fatima Shear Zone (FSZ).