Local groundwater governance in Yemen: building on traditions and enabling communities to craft new rules

Local groundwater management in Yemen and the means by which stakeholders can work together to improve water governance are discussed. In the last few decades the discourse on groundwater management in Yemen has increasingly been cast in terms of crisis, triggered by rapidly declining water tables around cities and in the main agricultural areas. However, in some places in Yemen, communities have responded by implementing local rules that have reduced conflict and provided more reliable and equitable access to water. This trend towards development of local groundwater governance is described, and could make a major contribution in realizing the goals of national water-sector policies and strategies. Twenty-four cases have been identified from different parts of the country and five cases are presented in detail. The article discusses how the process of local management could be nurtured and how it could contribute to rebalancing water use in several parts of Yemen.     

The study of environmental effects of chemical fertilizers and domestic sewage on water quality of Taft region, Central Iran

One of the important indicators to show the quality of water for drinking and irrigation is nitrate values in water and soil. Nitrate enters surface water and groundwater through degradation and decomposition of human and animal wastes, industrial productions, and agricultural runoff. The present paper focuses on the concentration of nitrite (NO₂ ^?1) and nitrate (NO₃ ^?1) of the groundwater in Taft region, Central Iran. Sixty-one samples of the region’s aqueducts, wells, and springs were collected in September 2008 and May 2009 and analyzed by ICP-MS method. However, distribution maps of nitrate and nitrite and their frequency diagram in the pertinent samples have been generated. Then, they were compared to the US Environmental Protection Agency (EPA) and WHO international standards. The mean of nitrate content measured in the samples was 18.52 mg/l, maximum was 115 mg/l which is higher than the EPA standard (i.e., 10 mg/l), and the mean of nitrite content was about 0.06 mg/l. According to the distribution maps, concentration of these anions is high in the downstream of settlements and farmlands of Taft region. With respect to the penetration of agricultural wastes, flooding irrigation, thin layer of alluvium, sandy texture, and the amount of fertilizer consumed in the region, and also absence of any natural source for these anions and absence of the major industrial activities in the region to produce sewage, it seems that nitrate and nitrite originated from the agricultural sewage and human waste. As the content of nitrate in drinking water in the region is higher than WHO and EPA standards, so there is the risk of methemoglobinemia disease in infants. In addition, nitrate content within the stomach and lungs interacts with amine and nitrosamines are made up which are potentially the initial cause of all cancers in human.     

Improved Water Quality Prediction with Hybrid Wavelet-Genetic Programming Model and Shannon Entropy

Natural Resources Research - Prediction of biochemical oxygen demand (BOD) as the main pollution indicators of organic pollution in freshwater resources is necessary. In the present work, a hybrid...     

Tectono-sedimentary events and geodynamic evolution of the Mesozoic and Cenozoic basins of the Alpine Margin,Gulf of Tunis,north-eastern Tunisia offshore

The structural pattern, tectono-sedimentary framework and geodynamic evolution for Mesozoic and Cenozoic deep structures of the Gulf of Tunis (north-eastern Tunisia) are proposed using petroleum well data and a 2-D seismic interpretation. The structural system of the study area is marked by two sets of faults that control the Mesozoic subsidence and inversions during the Paleogene and Neogene times: (i) a NE-SW striking set associated with folds and faults, which have a reverse component; and (ii) a NW–SE striking set active during the Tertiary extension episodes and delineating grabens and subsiding synclines. In order to better characterize the tectono-sedimentary evolution of the Gulf of Tunis structures, seismic data interpretations are compared to stratigraphic and structural data from wells and neighbouring outcrops. The Atlas and external Tell belonged to the southernmost Tethyan margin record a geodynamic evolution including: (i) rifting periods of subsidence and Tethyan oceanic accretions from Triassic until Early Cretaceous: we recognized high subsiding zones (Raja and Carthage domains), less subsiding zones (Gamart domain) and a completely emerged area (Raouad domain); (ii) compressive events during the Cenozoic with relaxation periods of the Oligocene-Aquitanian and Messinian-Early Pliocene. The NW–SE Late Eocene and Tortonian compressive events caused local inversions with sealed and eroded folded structures. During Middle to Late Miocene and Early Pliocene, we have identified depocentre structures corresponding to half-grabens and synclines in the Carthage and Karkouane domains. The north–south contractional events at the end of Early Pliocene and Late Pliocene periods are associated with significant inversion of subsidence and synsedimentary folded structures. Structuring and major tectonic events, recognized in the Gulf of Tunis, are linked to the common geodynamic evolution of the north African and western Mediterranean basins.     

Late Cryogenian arc-related volcaniclastic metasediment successions at Wadi Hammuda,Central Eastern Desert,Egypt: geology and geochemistry

Wadi Hammuda is dominated by a variety of low grade regionally metamorphosed volcaniclastic metasediments pertaining to two different geotectonic settings and intruded by arc and late collision granitic rocks. Thus, the volcaniclastic metasediments which form extensive outcrops are considered as a member of island arc assemblages. This paper deals with the petrography, geochemistry, and tectonic setting of the island arc volcaniclastic metasediment rock units. The volcaniclastic metasediments consist of interbedded metagreywackes, metasiltstones, metamudstones, and schists as well as metapyroclastics. They are well foliated, crenulated and tightly folded, metamorphosed, and intruded by granitic rocks. Geochemical data support the petrographic classification and reveal that these volcaniclastic metasediments are generally low-K, essentially tholeiitic in character, with the exception of some metasediments and metapyroclastics which exhibits calc-alkaline and tholeiitic affinities and represent the first stage of island arc volcanism. The overthrusted oceanic lithosphere blocks with fragments of the fore arc and/or back-arc marginal basins volcaniclastic metasediments were incorporated among the island arc volcanics which supported by tectonically relationship between the different rock units in the study area. Contemporaneous with this deformation event, Wadi Hammuda was subjected to low grade regional metamorphism and the rocks document an early phase of shearing and/or foliation. Occasionally minor folds were developed particularly in the metasediments and schists. The subsequent emplacement of the syn-tectonic granites (tonalites and granodiorites) resulted in minor local thrusts. During the regional thrusting event which preceded the emplacement of the late-tectonic granites (alkali feldspar granites) and affected the whole region, low grade successions cover the study area similar to the Meatiq volcaniclastic metasediments.     

Selenium transport and transformation modelling in soil columns and ground water contamination prediction

Selenium transport and transformation were simulated in a soil column. A one‐dimensional dynamic mathematical and computer model is formulated to simulate, selenate, selenite, selenomethionine, organic selenium, and gaseous selenium. This computer model is based on the mass balance equation, including convective transport, dispersive transport, surface adsorption, oxidation and reduction, volatilization, chemical and biological transformation. The mathematical solution is obtained by the finite difference implicit method. The model was verified by comparison of model results with experimental measurements and also using mass balance calculations in each time step of calculation. For example after 4 days of simulation, the simulated value of adsorbed selenate for depth of 20 cm is 0·2 µmol kg^?1 and the measured value is 0·25 µmol kg^?1. Therefore simulated results are in good agreement with measured values. With this study and its results the distribution of various forms of selenium in soil column to ground water table can be predicted. Copyright © 2008 John Wiley & Sons, Ltd.     

Correlation of the radiometric survey data and the structural analysis with the geology of Abu Zawal Area,Central Eastern Desert,Egypt

Abu Zawal area is located nearly north of the midway of Qena-Safaga road, and is about 250 square kilometres. It is built of a sequence of igneous and metamorphic rocks of Late Precambrian age.It has been subjected to geological, radiometrical, and structural investigations to reveal the structural setting of the area and its relation to the trends of mineralization, as well as the distribution of the radioactivity in the different rock units, cropping out in the studied area. Therefore, each rock unit has been characterized statistically by a certain radiometric background through the radiometric survey traverses. Besides, application of certain statistical inference tests could find the relations that might exist between the different rock types of Abu Zawal area and their corresponding ones in other studied areas.It has been found that the least radioactivity is associated with the basic metavolcanic rocks, while the highest values are associated with the Late Orogenic Plutonites and related rocks, and the granodiorites represent a moderate level of radioactivity. The study revealed that the Late Orogenic Plutonites of Abu Zawal area might be of younger age than their corresponding ones at the north of the Eastern Desert.Investigation of the two conjugate shear joints for the whole area and those for the granodioritic rocks, in the studied area, could indicate that every rock type has been subjected to different forces, but the complementary of all the forces acting on the studied area has a strike N 28° W. This is consistent with the interpretations of different authors which tend to the fact that the Eastern Desert of Egypt has been subjected to a compressive force of northwesterly direction.Investigation of the tension planes along which mineralization is possible, could reveal that the area is subjected to the first case of stress-strain ellipsoid in which tension fractures are formed at right angle to the greatest strain axis, while shear fractures are formed passing through the intermediate strain axis which make an angle of about 30° with the least strain axis.The structural trend analysis realized four tectonic trends having preferable orientation in the E-W, N-S, NW-SE, and NE-SW directions, of which the E-W is the oldest trend.

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Zusammenfassung Das Untersuchungsgebiet Abu Zawal liegt nördlich der Straße Qena-Safaga, etwa auf halber Strecke. Es ist etwa 250 km² groß und wird aus magmatischen und metamorphen Gesteinen spätpräkambrischen Alters aufgebaut.Das Gebiet wurde geologisch, radiometrisch und strukturgeologisch untersucht im Hinblick auf den Bau der Region und seiner Beziehungen zur Mineralisation und zur Verteilung der Radioaktivität in den verschiedenen Gesteinseinheiten. Entlang radiometrischer Meßprofile wurde jeder Gesteinskomplex statistisch bezüglich seines radioaktiven Untergrundes charakterisiert. Mit bestimmten statistischen Vergleichstests könnten sich Beziehungen zwischen den Gesteinstypen des Gebietes von Abu Zawal und entsprechenden anderer untersuchter Gebiete feststellen lassen.Die geringste Radioaktivität wurde in den basischen metavulkanischen Gesteinen beobachtet, die höchsten Werte dagegen in den spätorogenen Plutoniten. Die Granodiorite besitzen mittlere Radioaktivität. Die Untersuchung hat ergeben, daß die spätorogenen Plutonite des Gebietes von Abu Zawal jünger sein könnten als die entsprechenden Gesteine im Norden der Eastern Desert.Die Untersuchung der beiden konjugierten Schersysteme des gesamten Gebietes wie der granodioritischen Gesteine zeigt, daß jeder Gesteinstyp zwar verschiedenen Kräftefeldern ausgesetzt war, daß aber das Komplement aller Kräfte, die auf das Untersuchungsgebiet wirkten, die Streichrichtung N 28° W (i.e. 152°) besitzt. Dieses stimmt mit den Interpretationen verschiedener Autoren überein, die in der Eastern Desert Ägyptens ein Gebiet sehen, daß einer Kompression aus nordwestlicher Richtung ausgesetzt war.Die Untersuchung von Zerrungsklüften, in denen Mineralisation erfolgen kann, ließ erkennen, daß das Gebiet dem ersten Fall des Strain-Stress-Ellipsoids ausgesetzt war, bei dem die Zerrungsbrüche senkrecht zur Achse der größten Druckspannung erfolgt sind. Die Scherbrüche sind dagegen entlang der Achse der mittleren Druckspannung entstanden, die einen Winkel von ca. 30° mit der Achse des geringsten Druckes bildet.Die strukturelle Analyse ließ vier tektonische Trends erkennen mit den Hauptrichtungen E-W, N-S, NW-SE und NE-SW, von denen die EW-Richtung die älteste ist.

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Résumé La région d'Abu Zawal est située approximativement à mi-chemin au nord de la route Qena-Safage, et couvre environ 250 km². Elle est formée par une série de roches ignées et métamorphiques d'âge précambrien supérieur. - Elle a été étudiée du point de vue gé ologique, radiométrique et structural en vue de reconnaître sa position structurale et sa relation avec les tendances minéralisatrices, ainsi que la répartition de la radioactivité dans les différentes unités. Chaque unité a donc été caractérisée statistiquement par un certain fond radiométrique à l'aide de traverses radiométriques. En outre l'application de certains tests d'inférence statistique a pu trouver les relations pouvant exister entre les différents types de roches de la région d'Abu Zawal et leurs correspondants dans d'autres régions étudiées.La radioactivité la plus faible a été trouvée associée aux roches métavolcaniques basiques, tandis que les valeurs les plus élevées sont liées aux plutonites orogéniques tardives et aux roches qui leur sont associées; quant aux granodiorites, elles représentent un niveau de radioactivité modéré. - L'étude a révélé que les plutonites orogéniques tardives de la région d'Abu Zawal pourraient être plus jeunes que leurs correspondantes du Nord du Désert oriental.L'investigation des deux systèmes conjugués de joints de tension pour l'entièreté de l'étendue et de ceux relatifs aux roches granodioritiques dans l'étendue étudiée, pourrait indiquer que chaque type de roche a été soumis à des forces différentes, mais que le complémentaire de toutes ces forces ayant agi sur la région étudiée a une direction N 28° O. Ceci est en accord avec les interprétations des différents auteurs qui tendent à dire que le Désert oriental de l'Egypte a été soumis à une compression de direction nord-ouest. L'investigation des plans de tension le long desquels la minéralisation est possible pourrait révéler que la région est soumise au premier cas de l'ellipsoïde strain-stress dans lequel les fractures de tension sont à angle droit de l'axe maximum des efforts, tandis que les fractures de cisaillement se forment le long de l'axe intermédiaire des forces qui fait un angle d'environ 30° avec l'axe des efforts minimum.L'analyse structurale des directions a permis de reconnaître 4 directions tectoniques dont l'orientation dominante est E - O, N - S, NO - SE et NE - SO, parmi lesquelles la direction E - O est la plus ancienne.

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Fluctuating asymmetry in grass goby Zosterisessor ophiocephalus Pallas, 1811 inhabiting polluted and unpolluted area in Tunisia

Fluctuating asymmetry, a random deviation of bilateral traits, is assessed on grass goby Zosterisessor ophiocephalus Pallas, 1811 living in one disturbed site and in one unpolluted site Gulf of Gabes (Tunisia). Statistical analysis showed that assessed asymmetries are fluctuating. FA of orbital diameter, sub-orbital distance, pectoral fin and post-orbital length are higher in polluted site compared to control. Chemical pollution seems to be responsible for this high FA.     

Evaluation of the effectiveness of carbonaceous adsorbents on simultaneous extraction of heavy metals: a comparative study

A solid-phase extraction procedure was described for the quantitative extraction of a mixture of lead, cadmium, copper and bismuth ions on modified multiwalled carbon nanotubes, graphene oxide nanosheets, activated carbon and carbon black, individually. Then, the adsorbed analytes were eluted with HCl and introduced directly to electrothermal atomic absorption spectrometry. The surface morphology of the adsorbents was investigated by field-emission scanning electron microscopy. The parameters affecting the adsorption–elution process such as pH and flow rate of the sample solution—type, concentration, volume and flow rate of eluent were optimized in detail. Adsorption capacities, breakthrough volumes and enrichment factors were also studied. Wide calibration curves with good correlation coefficients, low detection limits and acceptable relative standard deviations were obtained for all analytes on different adsorbents. The results showed, when nanoadsorbents were used, higher adsorption and recoveries were obtained for all of the studied metal ions. The proposed method has been applied to the determination of Pb(II), Cd(II), Cu(II) and Bi(III) in water, wastewaters, human urine and human hair samples. The spiked recoveries were in the range 93.0–106%. Also, the accuracy of the method was validated by analyzing a certified reference material.