Hydrochemical processes determining the groundwater quality for irrigation use in an arid environment: The case of Liwa Aquifer, Abu Dhabi, United Arab Emirates

© 2018 Evaluation of groundwater quality is very important in arid regions like United Arab Emirates where high evaporation rates and absence of present-day recharge coupled with increasing groundwater extraction may limit its use for irrigation purposes. The liwa aquifer in Abu Dhabi Emirate is known for its intensive agriculture activities which depend on groundwater exploitation. The objective of the study was to determine the hydrochemical processes governing the groundwater chemistry, evaluation of groundwater quality and suitability for irrigation use. In the present study, 41 groundwater samples were collected from Liwa area in Abu Dhabi and analyzed for various physiochemical parameters such as pH, total dissolved solids (TDS), electrical conductivity (EC), Na+, K+, Ca2+, Mg2+, CO3−, HCO3−, Cl−, SO42−, NO3- and heavy metals. Electrical conductivity varies between 328 and 3003 uS/cm with an average value of 1478.5 uS/cm. Results show that changes in the groundwater chemistry is mainly controlled by rock weathering, to some extent evaporation and agricultural activities. The sodium ion was the main cation with an average value of 2923.2 mg/L, while the chloride ion was the dominant anion with an average value of 5670.8 mg/L. The water in the study area is mostly saline due to the dominance of these two ions. According to piper diagram, the main groundwater type in the study area was Na-Cl-SO4 type. The suitability for agriculture use was assessed using sodium absorption ratio (SAR), sodium percentage (Na%), residual sodium concentration (RSC), Kelley\u27s ratio, and magnesium hazard. Results showed that the groundwater quality in the study area is not suitable for irrigation

Concentration and distribution of selenium in Iranian coals

AbstractAbout 478 coal and coaly shale samples were collected to study the selenium content and distribution pattern in Iranian coals in different coal basins. Most Iranian coals have selenium coals lower than 31.5ppm. The average Se content in Iranian coals is about 1.2ppm, close to that in the world. The Ksashan coal basin has lowest levels of average Se (0.9ppm) accumulation. The Se concentration in Iranian coals is influenced by metamorphism and tectonic conditions. The highest concentration of Se in coal-bearing deposits is at Kalishur (31.5ppm) in Tabas coal basin

Predictive Cu porphyry potential mapping using fuzzy modelling in Ahar–Arasbaran zone, Iran

Fuzzy set theory was successfully used to map areas of copper porphyry mineralization potential in the Ahar–Arasbaran district of Iran. Proximity to geological features is translated into fuzzy membership functions based upon qualitative and quantitative knowledge of spatial associations between known Cu porphyry occurrences and geological features in the area. Fuzzy sets of favourable lithology, geochemical anomaly, geophysical anomaly, structural feature, and alterations are combined using fuzzy logic as the inference engine. The fuzzy predictive maps delineate 84% of the known Cu porphyry occurrences. The results demonstrate the usefulness of a geologically constrained fuzzy set approach to map mineral potential and to redirect surficial exploration work in the search for yet undiscovered Cu porphyry mineralization in the mining district. The method described is applicable to other mining districts elsewhere

Hydrogeochemical and spectroscopic studies of radioactive materials in Ayrakan and Cheshmeh Shotori areas, northeastern Isfahan province

Groundwaters hydrochemistry of Ayrakan and Cheshmeh Shotori areas and geochemistry of rare earth elements, indicate Ayrakan alkali granite as the origin of uranium and other dissolved elements in groundwaters of these areas. Geochemical and hydrogeochemical studies as well as the trend of uranium and thorium transition and mobility in aqueous environments of these areas indicate uranium adsorption by iron hydroxide (goethite) as the deterrent agent against uranium transition and mobility from depth to surface. Gamma-ray spectroscopic study of sediments from Cheshmeh Shotori area by HPGe detector indicates the presence of 226Ra in high contents and as the radioactive nuclide that is the reason for high activity of these sediments. Production of 226Ra from 238U decay, shorter half-life of 226Ra compared to 238U, radium transition by groundwaters from depth to surface as well as hydrogeochemical evidences, all suggest the possibility of existence of hidden uranium deposit and uranium mineralization in depth and the distance between Ayrakan and Cheshmeh Shotori areas