Mustafa Al Kuisi

Groundwater vulnerability to selenium in semi-arid environments: Amman Zarqa Basin, Jordan

An evaluation of ~250 samples of groundwater in the Amman Zarqa Basin for selenium along with other major and trace elements showed that concentrations of Se ranged between 0.09 and 742xa0μg/L, with an average value of about 24xa0μg/L. Selenium concentrations exceeded the recommended threshold for drinking water of the World Health Organization (WHO; 10xa0μ/L of Se) in 114 samples, with greater than 50xa0μg/L (quantity equivalent to the Jordanian standard of the allowed concentration of the element in water) of Se in nine cases. The average concentrations of Se in the lower, middle, and upper aquifers of the basin were 3.41, 32.99, and 9.19xa0μg/L, respectively. Based on the correlation with geologic formations and the statistical analysis of major/minor constituents and Piper tri-linear diagrams, we suggest that carbonate/phosphate dissolution, oxidation–reduction processes, and fertilizers/irrigation return flow are, together, the primary factors affecting the chemistry of the groundwater. Factor analysis helped to define the relative role of limestone-dolomitic dissolution in the aquifers (calcium, magnesium, and bicarbonate), agricultural activities (sulfate, nitrates, phosphorus, and potassium), oxidation–reduction factor (Eh, Fe, Mn, Cu, Zn, and Se), and anthropogenic (industrial) factor (EC, Fe, Cr, Co, Zn, and As). The high variability in Se concentrations might be related to the possibility of a multi-source origin of Se in the area.

Hydrogeochemical modeling of the water seepages through Tannur Dam, southern Jordan

This paper reveals the geochemical processes of dissolution, precipitation and cation exchange that took place during water–rock interaction between water seepages through the Tannur Dam. The Schoeller diagram indicates that there are three major water types originating during water–rock interaction. The first water type is characterized by low salinity that ranges from 1,300 to 2,800xa0µs/cm, which represents the reservoir water and the water in the right side of the central gallery. The second water type is in the left side of the central gallery, which exhibits medium salinity that reaches about 4,400xa0µs/cm. The third water type is characterized by very high salinity that reaches a value of around 8,500xa0µs/cm and represents the water in the right existing adit. The increase of salinity can be explained due to the dissolution of carbonate and sulfate minerals that form the matrix of the foundation and the abutment rocks, and the dissolution of the grout curtain, which is composed of cement and bentonite. Hydrogeochemical modeling, using a computer code PHREEQC, was used to obtain the saturation indices of specific mineral phases, which might be related to interaction with water seepages, and to identify the chemical species of the dissolved ions. The thermodynamic calculations indicate that most of the water samples were undersaturated with respect to gypsum, anhydrite and halite, and were saturated and/or supersaturated with respect to calcite and dolomite. Ca(HCO3)2 is the primary water type, as a result of dissolution of carbonate minerals such as calcite and dolomite prevailing at the dam site. However, cation-exchange processes are responsible for the formation of the Na2SO4 water type from the CaSO4 type that formed due to the dissolution of gypsum.

Assessment of elemental distribution and heavy metals contamination in phosphate deposits: potential health risk assessment of finer-grained size fraction

The concentrations and chemical distributions of heavy metals (Cd, Cr, Ni, Zn, U, and V) in the Al-Jiza phosphate ores were investigated. Typically, the mean concentration values of Cd, Cr, Ni, U, and Zn are 15xa0±xa08, 109xa0±xa021, 34xa0±xa06, 211xa0±xa055, 142xa0±xa055, and 161xa0±xa057xa0mgxa0kg−1, respectively. On the other hand, the encountered average concentration values of Cd, Cr, Ni, Zn, U, and V in the phosphate dust particles (<0.053) were found to be 22xa0±xa05, 179xa0±xa05, 67xa0±xa011, 441xa0±xa014, 225xa0±xa058, and 311xa0±xa09xa0mgxa0kg−1, respectively. The contamination factors of U and Cr are greater than 1, indicating that these heavy metals could be potentially hazardous, if released to the environment. Multivariate statistical analysis allowed the identification of three main factors controlling the distribution of these heavy metals and the other chemical constituents. The extracted factors are as follows: francolite mineral factor, clay minerals factor, and diagenesis factor. Health risk assessments of non-cancerous effects in finer-grained size fraction that might be caused by contamination with the heavy elements have been calculated for both children and adults. The risk assessments in case of children for non-cancerous effects showed that U has values greater than the safe level of hazard index (HIxa0=xa01). In case of adults, the value of risk for U is also higher as compared to those of Cd, Ni, Cr, and Zn where it lies within the safe range of hazard index (HIxa0<xa01). Child health risk assessment indicates that children are more vulnerable to contaminants from phosphate mining than adults.

Spatial distribution patterns of molybdenum (Mo) concentrations in potable groundwater in Northern Jordan

Two hundred and three groundwater samples were collected during March 2011 to June 2012 from the B2/A7 aquifer water supply wells of northern part of Jordan. The physicochemical properties were analyzed in situ for the major cations, anions, while certain heavy metals were analyzed in the laboratory. Some oilshale rock samples were geochemically analyzed. The Upper Cretaceous aquifer (B2/A7) is used as water supply for most of the communities in the study area. It consists of limestone, marly limestone, bedded chert, and minor phosphorite. Hydrochemical results from the B2/A7 aquifer indicate two main water types: alkaline-earth water (CaHCO3) and alkaline-earth water with high alkaline component (NaHCO3–, Na2SO4). Standard column leaching experiments on oilshale rock samples and the R-mode factor analysis suggest that the sources for elevated Mo concentrations in the groundwater of certain parts of northern Jordan are attributed to water-oilshale interaction, mobility of Mo down to the groundwater and the extensive use of fertilizers within these areas. Molybdenum (Mo) concentrations in the groundwater water range from 0.07 to 1.44xa0mg/L with an average value of 98xa0μg/L. They are found to exceed the JISM and WHO guidelines in two areas in northern part of Jordan. Spatial distribution of Mo, using ordinary kriging techniques and the resulting map, shows high Mo concentration in the northwestern part near Wadi Al Arab area reaching concentrations of 650xa0μg/L and in the southeastern corner of the investigated area, south of Al Ukaydir village, with an average concentration of 468xa0μg/L. Both areas are characterized by extensive oilshale exposures with average concentration of 11.7xa0mg/kg Mo and intensive agricultural activities. These two areas represent approximately 33xa0% of the groundwater in the northern part of Jordan. Mobility of Mo to the groundwater in northern part of Jordan is attributed to two mechanisms. First, there is reductive dissolution of Fe-oxide, which releases substantial adsorbed Mo concentrations. Secondly, there is oxidation of Mo into dissolved forms in sulfide organic-rich system.

Hydrogeochemistry of groundwater from karstic limestone aquifer highlighting arsenic contamination: case study from Jordan

Groundwater wells in the Amman-Wadi Es Sir Aquifer (B2/A7) throughout Jordan are investigated for their arsenic (As) and element-by-element geochemical behavior. Groundwater wells are found to have total arsenic concentrations above the recommended levels designated by the Jordanian drinking water standard, the Environmental Protection Agency of the United States, and the World Health Organization. Arsenic distribution in the aquifer is variable, but it is detected with a concentration of ≥10xa0ppb in 87 samples out of the analyzed 150 groundwater samples, with a maximum concentration of 173xa0ppb. Elevated As concentrations can be attributed to several mechanisms. One of these mechanisms is accounted for to the interaction between groundwater and the natural phosphorite deposits in the upper part of the aquifer and oil shale deposits overlying it. The high significant correlation between arsenic, phosphorus, and calcium concentrations in the analyzed groundwater samples suggest that these elements are derived from the same source. Moreover, scanning electron microscopy shows the association of As with the P and Ca in the phosphorite; pyrite is present in the oil shale samples, which were collected from the Muwaqqar formation overlying the aquifer. EDAX analysis shows that substantial As concentrations are present in phosphate and pyrite. This study suggests that the major mechanism responsible for releasing As from the aquifer material into the groundwater is a simple dissolution reaction. However, Piper and Durov diagrams, correlation coefficients, and factor analysis all suggest that water interaction with phosphate and oil shale deposits, sorption of heavy metals, and simple dissolution of iron oxyhydroxides are together the primary factors affecting the chemistry of the groundwater and responsible for the elevated As values in some wells.

Groundwater resources assessment for irrigable agricultural lands in the Wadi Araba area, southern Jordan

The main target of this research paper was to the hydrogeological assessment of the groundwater resources to irrigate 600xa0ha of irrigable agricultural lands, distributed along the Dead Sea–Aqaba Highway in Umm, Methla, Wadi Musa, Qa’ Saideen and Rahma, southern Jordan. Therefore, a comprehensive groundwater study was commenced by drilling eight new wells which can be used to supply irrigable areas with the existing groundwater that would be enriched by the yield of three proposed recharge dams on Wadi Musa, Wadi Abu-Burqa, and Wadi Rahma. The evaluation of the pumping test data of the drilled was carried out using the standard methods of pumping test interpretation. This was based on the available water table measurements at well locations and knowledge of water flow in the general. The sustainable yield of each well was calculated based on the pumping test parameters. The obtained results indicate that pumping out of Beer Mathkor wells should not exceed 1,100xa0m3/day in the case of continuous pumping and 8,700xa0m3/day in the case of intermittent pumping. Since the water table did not significantly change with small changes in pumping (it took eightfolds of magnitude increase in pumping from approximately 1,100 to 8,700xa0m3/day to show a significant drop in the water table equivalent to about 5.5 MCM per year from the aquifer.

Accumulation and coarse mode aerosol concentrations and carbonaceous contents in the urban background atmosphere in Amman, Jordan

In this study, we analyzed the concentrations of accumulation and coarse modes measured during November 2013–July 2017 at an urban background site in Amman, Jordan. The concentrations showed distinct seasonal variations with high concentrations with a monthly average higher than 100xa0cm−3 and 1.5xa0cm−3, respectively, for accumulation and coarse modes during the winter and low concentrations with a monthly average less than 40xa0cm−3 and 1–1.5xa0cm−3, respectively, for accumulation and coarse modes during the summer. Sand and dust storms (SDS) affected the coarse mode during the early spring whereas local dust re-suspension affected them during the autumn. The gravimetric analysis confirmed the seasonal variation of the calculated particulate mass concentration but suggested that the assumption of spherical particles and unit density is not always proper. The ATR-FTIR analysis of selected filters revealed that aerosols in the background atmosphere of Amman are a mixture of locally emitted (fossil fuel combustion) and local/regional dust. Based on the 24-h average of the calculated PM10, the pollution standard index (PSI) revealed that about 81% of the days were either good or moderate air quality conditions. About 71% of the days were below the 24-h PM10 limit value according to the Jordanian air quality standards (120xa0μgxa0m−3).