Degradation of Malathion and Parathion by Ozonation,Photolytic Ozonation,and Heterogeneous Catalytic Ozonation Processes

The oxidation of organophosphorus pesticides (OPPs), such as malathion and parathion, in aqueous solution was studied using conventional ozonation (O₃), photolytic ozonation (O₃/UV, O₃/UV/H₂O₂), and heterogeneous catalytic ozonation (O₃/TiO₂/UV) processes. Experiments were performed in batch mode at laboratory scale and processes were compared in terms of disappearance kinetics. The best results of pesticide mineralization were obtained when TiO₂ particles in combination with ozone (O₃) and UV photolysis (λ = 254 nm) were applied. Decomposition of 99% of parent compounds were achieved in 10 min and oxon derivatives were completely removed in 30 min. The initial reaction rate increases linearly with increasing catalyst amount. Toxicity measurements of the treated solutions were carried out in order to evaluate the efficiency of the treatment methods. No detoxification was achieved for O₃ and O₃/UV applications. Heterogeneous photocatalytic ozonation was shown to be feasible for achieving complete decomposition of OPPs and their oxon intermediates.     

Model‐based attenuation for scattered dispersive waves

Coherent noise in land seismic data primarily consists in source‐generated surface‐wave modes. The component that is traditionally considered most relevant is the so‐called ground roll, consisting in surface‐wave modes propagating directly from sources to receivers. In many geological situations, near?surface heterogeneities and discontinuities, as well as topography irregularities, diffract the surface waves and generate secondary events, which can heavily contaminate records. The diffracted and converted surface waves are often called scattered noise and can be a severe problem particularly in areas with shallow or outcropping hard lithological formations. Conventional noise attenuation techniques are not effective with scattering: they can usually address the tails but not the apices of the scattered events. Large source and receiver arrays can attenuate scattering but only in exchange for a compromise to signal fidelity and resolution. We present a model?based technique for the scattering attenuation, based on the estimation of surface‐wave properties and on the prediction of surface waves with a complex path involving diffractions. The properties are estimated first, to produce surface?consistent volumes of the propagation properties. Then, for all gathers to filter, we integrate the contributions of all possible diffractors, building a scattering model. The estimated scattered wavefield is then subtracted from the data. The method can work in different domains and copes with aliased surface waves. The benefits of the method are demonstrated with synthetic and real data.     

Ambient seismic vibration analysis and ground characterization in the vicinity of Algiers seismic zone

The Dar El Beida area, situated in the Mitidja basin, in the north central Tellian Atlas is characterized by its Plio-Quaternary sediments. The site effect analysis in this zone surrounding Algiers city is very important. The soil is constituted from recent soft sediments capable of amplifying seismic motion. Indeed, the analysis thanks to the ratio H/V ambient vibration method confirms these assumptions. An electric resistivity tomography strengthened the results obtained from ambient vibration for site characterization. This demonstrates once again the more or less homogeneous character of formations in this area. However, strongly amplifying its sediments largely explains the seismic acceleration of 0.52 g recorded following the 2003 Boumerdes earthquake.     

Late Eocene-early Miocene palaeogeographic evolution of central eastern Anatolian basins,the closure of the Neo-Tethys ocean and continental collision

In central eastern Anatolia which is located between Eurasia and Africa, the study of basin developments between late Eocene and early Miocene is of great importance for understanding the process of the closure of the Neo-Tethys Ocean and the formation of strike-slip faults and regional uplift. To study these, three basins were selected: the Sivas-Erzincan, Gürün-Akkisla-Divrigi (GAD), and Malatya basins. The study proposes that the opening of the GAD basin played a key role in the formation of the Ecemis fault, which started developing at the end of early Miocene, and in mountain uplift. All these basins are situated on continental blocks and oceanic crust, arranged from north to south as the Sakarya continent, the Izmir-Ankara-Erzincan ocean (Northern Neo-Tethys), the Kirsehir continent, the inner Tauride ocean, the Munzur-Binboga block, the Maden (=Berit) ocean, the Bitlis-Pütürge block, the Çüngüs ocean and the Arabian continent.The findings indicate that late Eocene-early Miocene successions in these basins were not deposited in foreland basins formed in front of the thrust faults associated with the closure of the ocean, as stated in previous studies. Rather, they were deposited in forearc and backarc basins related to the subduction which was effective until the end of early Miocene. The Sivas-Erzincan and Malatya basins, located on the inner Tauride and Maden (=Berit) oceans, were forearc basins, while the GAD basin situated on the Munzur-Binboga block was a backarc basin. These basins have parallel developments up to the end of early Miocene. While marine sediments were deposited in the Malatya and Sivas-Erzincan basins between late Eocene and early Miocene, terrestrial units began to settle in the GAD basin from the late Eocene and the deposition there is continuous until the end of the early Miocene.Collision of the Arabian and the Anatolian plates at the end of early Miocene (16-18 Ma) produced the left-strike slip Ecemis fault zone, which caused the lateral slip of sedimentary units in the Sivas-Erzincan and GAD basins over hundreds of kilometers. This event produced the first westward tectonic escape of the Anatolian plate prior to the north Anatolian fault (NAF) and the east Anatolian fault (EAF). The Gürün region located in the GAD basin was exhumed in late Miocene and this basin was broken. The Gürün region, which remains on the rising part of the Munzur-Binboga block, is not a different basin as stated earlier, but it is a part of the GAD basin, representing the central part of the GAD basin lake, as indicated by the fine grained deposits (limestones and clay) that occur in the Gürün area.     

Delineation of saltwater intrusion zones using the time domain electromagnetic method: the Nabeul–Hammamet coastal aquifer case study (NE Tunisia)

The time domain electromagnetic method (TDEM) is applied to monitor, to delineate and to map the saltwater intrusion zones in the Mediterranean Plio‐Quaternary aquifer. Forty‐two TDEM soundings were carried out in the coastal plain of Nabeul–Hammamet region (NE Tunisia). TDEM resistivity data were correlated with the existing borehole logging data to assign them to a particular lithology and to provide information about the position of the freshwater–seawater transition zone. The geoelectric sections showing the vertical configuration of seawater intrusion, with the brackish‐salty‐saturated zones, have a resistivity ranging from ~0.1 to 5 Ω?m and are detected at a depth lower than 1.5 m. The salinized zones are located at Nabeul (Sidi Moussa, Sidi El Mahrsi, Al Gasba and Mrazgua) and at Hammamet (Touristic zone of Hammamet north and south, Baraket Essahel) and reached a distance of 4 km from the coastline, indicating a severe state for the aquifer in these zones. These TDEM results are confirmed by the increase of chloride concentration content in the analysed water samples of monitoring wells. Moreover, in the northeastern part, the presence of a saltwater front located far from the coast and along the NW–SE major surface fault can be explained by two hypothesis: (i) this fault seems to provide a conduit for seawater to move readily towards the water wells and (ii) the clay and gypsum infiltration of marine Messinian deposits through the fault plane leads to low resistivities. Finally, it comes out from this study that TDEM survey has successfully depicted salinized zones of this coastal aquifer. Copyright © 2012 John Wiley & Sons, Ltd.     

Environmental problems at the Nevşehir (Kozakli) geothermal field,central Turkey

The Kozakli–Nev?ehir geothermal field extends a long a NW–SE direction at SE of the Centrum of Kozakli. The area is not rugged and average elevation is 1,000 m. The Kozanözü Creek flows towards north of the area. In the Kozakli thermal Spa area, thermal waters are manifested along a valley with a length of 1.5 km and 200 m width. In this resort some hot waters are discharged with no use. The thermal water used in the area comes from wells drilled by MTA. In addition, these waters from wells are also utilized by hotels, baths and motels belonging to City Private Management, Municipality and private sector. The measured temperature of Kozakli waters ranges from 43–51°C in springs and 80–96°C in wells. Waters are issued in a wide swampy area as a small group of springs through buried faults. Electrical conductivity values of thermal spring and well waters are 1,650–3,595 μS/cm and pH values are 6.72–7.36. Kozakli cold water has an electrical conductivity value of 450 μS/cm and pH of 7.56. All thermal waters are dominated by Na⁺ and Cl–SO₄ while cold waters are dominated by Ca⁺² and HCO₃ ^?. The aim of this study was to investigate the environmental problems around the Kozakli geothermal field and explain the mechanisms of karstic depression which was formed by uncontrolled use of thermal waters in this area and bring up its possible environmental threats. At the Kozakli geothermal field a sinkhole with 30 m diameter and 15 m depth occurred in January, 17th 2007 at the recreation area located 20 m west of the geothermal well which belongs to the government of Nev?ehir province. The management of the geothermal wells should be controlled by a single official institution in order to avoid the creation of such karstic structures affecting the environment at the source area.     

Hydrochemical analysis and evaluation of groundwater quality of a Mio-Plio-Quaternary aquifer system in an arid regions: case of El Hancha, Djebeniana and El Amra regions, Tunisia

A hydrogeochemical approach has been carried out in the Mio-Plio-Quaternary aquifer system of northern Sfax to investigate the geochemical evolution, the origin of groundwaters and their circulation patterns. The groundwater samples collected from different wells seem to be dominated by sodium chloride type to sulphate chloride type. Detail analysis of chemical data including the thermodynamic calculations was used to assess that the chemical evolution of groundwater is primarily controlled by water–rock interactions. The values of sodium absorption ratio and electrical conductivity of the groundwater were plotted in the US Salinity Laboratory diagram for irrigation water. Most of the water samples in northern Sfax fall in the fields of C4S1, C4S2 and C4S3 indicating very high salinity and medium to high sodium alkalinity hazard. Thus, groundwater quality is ranging between doubtful to unsuitable for irrigation uses under normal condition, and further action for salinity control is required in remediating such problem. Principal component analysis of geochemical data used in conjunction with bivariate diagrams of major elements indicates that groundwater mineralization is mainly controlled by (1) water–rock interaction processes, (2) anthropogenic process in relation with return flow of NO₃-rich irrigation waters and (3) domestic discharges.     

Hydrous aluminosilicate metasomatism in an intra-oceanic subduction zone: Implications from the Kurancali (Turkey) ultramafic-mafic cumulates within the Alpine Neotethys Ocean

The Kurancali ultramafic-mafic cumulate body, an allochthonous ophiolitic sliver in central Anatolia, is characterized by the presence of abundant hydrous phases (phlogopite, pargasite) besides augitic diopside, plagioclase, and accessory amounts of rutile, sphene, apatite, zircon, and calcite. Based on modes of the essential minerals, the olivine-orthopyroxene-free cumulates are grouped as clinopyroxenite, hydrous clinopyroxenite, phlogopitite, hornblendite, layered gabbro, and diorite. Petrographical, mineralogical and geochemical features of the rocks infer crystallization from a hydrous magma having high-K calc-alkaline affinity with slightly alkaline character, and point to metasomatised mantle as the magma source. Our evidence implies that the metasomatising component, which modified the composition of the mantle wedge source rock in an intra-oceanic subduction zone, was a H₂O, alkali and carbonate-rich aluminosilicate fluid and/or melt, probably derived from a subducted slab. We suggest that the metasomatic agents in the subarc mantle led to the generation of a hydrous magma, which produced the Kurancali cumulates in an island-arc basement in a supra-subduction-zone setting during the closure of the Izmir-Ankara-Erzincan branch of the Alpine Neotethys Ocean.