Publications by authors named "Ahmed A Al-Taani"

16 Publications

  • Page 1 of 1

Assessment of Metals Concentrations in Soils of Abu Dhabi Emirate Using Pollution Indices and Multivariate Statistics.

Toxics 2021 Apr 25;9(5). Epub 2021 Apr 25.

SC. Utilnavorep SA, 55 Aurel Vlaicu Bd., 900055 Constanța, Romania.

The aim of this study was twofold. Firstly, we performed a land capability class determination of the agricultural soils from the Abu Dhabi Emirate, the United Arab Emirates, based on the concentrations of 17 chemical elements determined in the soil samples collected from 84 locations. Secondly, we assess the soil pollution with different metals, using several pollution indices. The results of Principal Component Analysis (PCA) shows that four principal components (PCs) are responsible for describing the total metals concentrations' variance, the highest contribution on PC1 being that of Mn, and Cr, on PC2 that of Fe, on PC3 that of Cu, and on PC4 that of Al. After determining the optimal number of clusters, we classified the sites into three clusters, while the studied metals were grouped function on their concentrations. Then, we used five indices to assess the pollution level of the soil at the study sites and in the clusters. The geo-accumulation index (I) indicates uncontamination/moderately contamination with Cu in cluster 1, uncontaminated/moderately contaminate soils with Cd, Cu, and Ni in cluster 2, and uncontaminated/moderately contaminated soil with Cu and moderately contaminated with Pb, Zn, and Ni in cluster 3. By comparison, the enrichment factors overestimate the pollution of the studied sites. The pollution load index (PLI) indicates a baseline level of pollution at 14 sites and the deterioration of the soil quality at four sites. The Nemerow pollution index provides similar results as PLI.
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http://dx.doi.org/10.3390/toxics9050095DOI Listing
April 2021

Contamination Assessment of Heavy Metals in Agricultural Soil, in the Liwa Area (UAE).

Toxics 2021 Mar 10;9(3). Epub 2021 Mar 10.

S.C. Utilnavorep S.A., 55 Aurel Vlaicu Bd., 900055 Constanta, Romania.

The Liwa area is a primary food production area in the United Arab Emirates (UAE) and has intensively been used for agriculture. This study investigates the pollution levels with heavy metals in agricultural soils from the Liwa area. Thirty-two soil samples were analyzed for Mn, Zn, Cr, Ni, Cu, Pb, Cd, Co, and As. Results revealed that heavy metal levels varied in the ranges 220.02-311.21, 42.39-66.92, 43.43-71.55, 32.86-52.12, 10.29-21.70, 2.83-8.84, 0.46-0.69, 0.03-0.37 mg/kg for Mn, Zn, Cr, Ni, Cu, Pb, Cd, Co, and As, respectively. All samples presented low As concentrations with an average of 0.01 mg/kg. The variations in bulk metal contents in the soil samples were related to multiple sources, including agrochemicals, atmospheric dust containing heavy metals, and traffic-related metals. Enrichment factor analysis indicates that Cd, Ni, Zn, and Cr were highly enriched in soils, and they could originate from non-crustal sources. Based on the geo-accumulation index (I), the soil samples appeared uncontaminated with Mn, Cr, Zn, Pb, Co, As, Cu, uncontaminated to moderately contaminated with Ni and moderately contaminated with Cd. The contamination factors suggest low contamination, except for Ni, which showed moderate contamination. The average pollution load index (PLI) revealed unpolluted to low pollution of all soil samples. The ecological risk assessment (PERI) showed that all heavy metals posed a low risk, except for Cd which exhibited a high ecological risk.
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http://dx.doi.org/10.3390/toxics9030053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8000652PMC
March 2021

Efficient removal of phenol compounds from water environment using Ziziphus leaves adsorbent.

Sci Total Environ 2021 Mar 24;761:143229. Epub 2020 Oct 24.

Department of Life and Environmental Sciences, College of Natural & Health Sciences, Zayed University, Abu Dhabi, United Arab Emirates; Department of Earth and Environmental Sciences, Yarmouk University, Jordan.

Industrial processes generate toxic organic molecules that pollute environment water. Phenol and its derivative are classified among the major pollutant compounds found in water. They are naturally found in some industrial wastewater effluents. The removal of phenol compounds is therefore essential because they are responsible for severe organ damage if they exist above certain limits. In this study, ground Ziziphus leaves were utilized as adsorbents for phenolic compounds from synthetic wastewater samples. Several experiments were performed to study the effect of several conditions on the capacity of the Ziziphus leaves adsorbent, namely: the initial phenol concentration, the adsorbent concentration, temperature, pH value, and the presence of foreign salts (NaCl and KCl). The experimental results indicated that the adsorption process reached equilibrium in about 4 h. A drop in the amount of phenol removal, especially at higher initial concentration, was noticed upon increasing the temperature from 25 to 45 °C. This reflects the exothermic nature of the adsorption process. This was also confirmed by the calculated negative enthalpy of adsorption (-64.8 kJ/mol). A pH of 6 was found to be the optimum value at which the highest phenol removal occurred with around 15 mg/g at 25 °C for an initial concentration of 200 ppm. The presence of foreign salts has negatively affected the phenol adsorption process. The fitting of the experimental data, using different adsorption isotherms, indicated that the Harkins-Jura isotherm model was the best fit, evident by the high square of the correlation coefficient (R) values greater than 0.96. The kinetic study revealed that the adsorption was represented by a pseudo-second-order reaction. The results of this study offer a basis to use Ziziphus leaves as promising adsorbents for efficient phenol removal from wastewater.
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http://dx.doi.org/10.1016/j.scitotenv.2020.143229DOI Listing
March 2021

Baseline marine investigation and impact of fish farming on the marine environment in Jebel Ali, Dubai, United Arab Emirates.

Mar Pollut Bull 2020 Oct 16;159:111468. Epub 2020 Jul 16.

College of Natural & Health Sciences, Zayed University, P.O. Box 144534, Abu Dhabi, United Arab Emirates.

Scattered seashells were observed on the seabed with no marine corals. The baseline studies indicate that biodiversity decreased from the northeast to southwest direction. The dominant groups of phytoplankton were diatoms followed by dinoflagellates, with insignificant vertical variations in species composition and population due to shallow water. The benthic diversity over the majority of the study area was relatively low compared with other nearshore areas in the region. All subtidal habitats showed evidence of disturbance to varying degrees, with no fish species recorded at these locations. The soft sediment habitat was found to cover much of the area footprint, and faunal diversity was very low. Fish diversity and abundance were equally poor with only a few demersal species recorded. No evidence of coral colonization was recorded although the presence of a low-profile, encrusting species was recorded in close proximity, to the east of the study area. Mangrove, coral, and seagrass were absent in the study area and its immediate vicinity. Modelling of waste plume suggested that the harbor water is fairly well-mixed, and the dispersion of ammonia attenuates with distance.
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http://dx.doi.org/10.1016/j.marpolbul.2020.111468DOI Listing
October 2020

Correlation of Blood Oxidative Stress Parameters to Indoor Radiofrequency Radiation: A Cross Sectional Study in Jordan.

Int J Environ Res Public Health 2020 06 29;17(13). Epub 2020 Jun 29.

Department of Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy, Yarmouk University, Shafiq Irshidat st Irbid 21163, Jordan.

: Electromagnetic pollution is a general health concern worldwide, as cell phone towers are ubiquitous and are located adjacent to or on the roof of schools, and hospitals. However, the health risks are still inconclusive. This cross-sectional study evaluated the potential effect of electromagnetic radiation generated from various resources including cell phone towers on blood glutathione S transferase activity (e-GST) and total antioxidant activity of the Jordanian population. : The power density of three districts in the city of Irbid, Jordan was mapped to generate "outside the houses" and "inside the houses" maps. The effect of categorical variables (gender, using a cell phone, presence of Wi-Fi modem, previous exposure to medical imaging) and continuous variables (distance from the base station, the elevation of the house, the duration of stay in the house, power density outside houses, power density inside houses) on e-GST and total antioxidant activity were investigated. : The EMR generated outside the houses-including cell phone towers-did not reach inside the houses at the same power and had no significant influence on e-GST activity. The EMR inside the house, which primarily came from internal resources, has a significant effect on e-GST activity. The duration of stay inside the house, the use of cell phones, and the presence of a Wi-Fi modem had a proportional effect on e-GST activity. The total antioxidant activity was statistically equal between the tested and control groups. : Several factors such as building materials restricted the penetration of EMR reaching inside the houses. EMR generated inside rather than outside the houses had a proportional effect on e-GST. The differences in e-GST were compensated successfully by other antioxidant mechanisms. Further research is needed to identify other possible sources of antioxidants, and to evaluate long-term effects and genetic polymorphism.
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http://dx.doi.org/10.3390/ijerph17134673DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7369753PMC
June 2020

Optimal conditions for olive mill wastewater treatment using ultrasound and advanced oxidation processes.

Sci Total Environ 2020 Jan 31;700:134576. Epub 2019 Oct 31.

Department of Chemical Engineering, Qatar University, Qatar; Planning and Statistics Authority, Doha, Qatar. Electronic address:

The treatment of olive mill wastewater (OMW) in Jordan was investigated in this work using ultrasound oxidation (sonolysis) combined with other advanced oxidation processes such as ultraviolet radiation, hydrogen peroxide (HO) and titanium oxide (TiO) catalyst. The efficiency of the combined oxidation process was evaluated based on the changes in the chemical oxygen demand (COD). The results showed that 59% COD removal was achieved within 90 min in the ultrasound /UV/TiO system. A more significant synergistic effect was observed on the COD removal efficiency when a combination of US/UV/TiO (sonophotocatalytic) processes was used at low ultrasound frequency. The results were then compared with the COD values obtained when each of these processes was used individually. The effects of different operating conditions such as, ultrasound power, initial COD concentration, the concentration of TiO, frequency of ultrasound, and temperature on the OMW oxidation efficiency were studied and evaluated. The effect of adding a radical scavenger (sodium carbonate) on the OMW oxidation efficiency was investigated. The results showed that the sonophotocatalytic oxidation of OMW was affected by the initial COD, acoustic power, temperature and TiO concentration. The sonophotocatalytic oxidation of OMW increased with increasing the ultrasound power, temperature and HO concentration. Sonolysis at frequency of 40 kHz combined with photocatalysis was not observed to have a significant effect on the OMW oxidation compared to sonication at frequency of 20 kHz. It was also found that the OMW oxidation was suppressed by the presence of the radical scavenger. The COD removal efficiency increased slightly with the increase of TiO concentration up to certain point due to the formation of oxidizing species. At ultrasound frequency of 20 kHz, considerable COD reduction of OMW was reported, indicating the effectiveness of the combined US/UV/TiO process for the OMW treatment.
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http://dx.doi.org/10.1016/j.scitotenv.2019.134576DOI Listing
January 2020

Assessment of nitrate and nitrite levels in treated wastewater, soil, and vegetable crops at the upper reach of Zarqa River in Jordan.

Environ Monit Assess 2019 Feb 9;191(3):153. Epub 2019 Feb 9.

Department of Biological Sciences, Faculty of Science, Yarmouk University, Irbid, 21163, Jordan.

The purpose of this study is to examine the impact of treated wastewater irrigation on agricultural soils and vegetables along the upper reach of Zarqa River (Jordan). Multiple samples of reclaimed wastewater, soil pits from farms, and vegetables (spinach, parsley, cabbage cauliflower, radish, and onion) were collected and analyzed for pH, total dissolved solids (TDS), and/or NO and NO contents. The average levels of NO and NO in treated wastewater samples varied from 167.2 to 209.9 mg/l for NO and from 80.3 to 106.1 μg/l for NO. Values of TDS and pH exhibited relatively comparable spatial patterns, with higher values in the downstream channel and lower in the upper reach, adjacent to Al-Samra Wastewater Treatment Plant. The average values of NO and NO showed broadly decreasing trends down-gradient towards King Talal Dam. In soil pits, a marginal increase of pH values with depth was noted, whereas TDS showed a remarkable decrease in soil profile by ~ 2 to 3 folds. Concurrently, the levels of NO and NO in all soil pits markedly decreased from top to bottom. In vegetables irrigated with treated wastewater, substantially elevated levels of NO were observed, compared with those irrigated with rainwater, with leafy vegetables demonstrating higher levels than the root crops. Spinach exhibited higher capacity for NO accumulation (4614.1 mg/kg), while onion showed the lowest content (1722 mg/kg). The highest NO level was observed in parsley (1.19 mg/kg), and the lowest concentrations were found in cauliflower (0.25 mg/kg). The markedly high accumulation of NO in vegetables is an indicator of pollution activities around Zarqa River and poses potential health risks to humans when they are consumed.
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http://dx.doi.org/10.1007/s10661-019-7292-8DOI Listing
February 2019

Long-term trends in ambient fine particulate matter from 1980 to 2016 in United Arab Emirates.

Environ Monit Assess 2019 Feb 8;191(3):143. Epub 2019 Feb 8.

, Dubai, United Arab Emirates.

This paper presents the most comprehensive datasets of ambient fine particulate matter (PM) for the UAE from 1980 to 2016. The long-term distributions of PM showed the annual average PM concentrations constantly exceeded the EPA and WHO guidelines. They varied from 77 to 49 μg/m with an overall average of 61.25 μg/m. While the inter-annual variability in PM concentrations showed relatively a cyclic pattern, with successive ups and downs, it broadly exhibited an increasing trend, particularly, over the last 14 years. PM concentrations displayed a strong seasonal pattern, with greatest values observed during warm summer season, a period of high demand of electricity and dust events. The lowest values found in autumn are attributable to reduced demand of energy. Decreased atmospheric temperatures and high relative humidity coinciding with this period are likely to reduce the secondary formation of PM. The spatial changes in PM concentrations exhibited gradual downward trends to the north and northeast directions. Airborne PM is prevalent in the southern and western regions, where the majority of oil and gas fields are located. PM/PM ratio indicated that ambient aerosols are principally associated with anthropogenic sources. Peaks in PM/CO ratio were frequently observed during June, July, and August, although few were concurrent with March. This indicates that secondary formation plays an important role in PM levels measured in these months, especially as the photochemical activities become relatively strong in these periods. The lowest PM/CO ratios were found during September, October, and November (autumn) suggesting a considerable contribution of primary combustion emissions, especially vehicular emissions, to PM concentration. PM concentrations are positively correlated with sulfate levels. In addition to sea and dust aerosols, sulfate concentration in the coastal region is also related to fossil fuel burning from power plants, oil and gas fields, and oil industries. The population-weighted average of PM in UAE was 63.9 μg/m, which is more than three times greater than the global population-weighted mean of 20 μg/m.
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http://dx.doi.org/10.1007/s10661-019-7259-9DOI Listing
February 2019

Reservoir water quality: a case from Jordan.

Environ Monit Assess 2018 Sep 22;190(10):604. Epub 2018 Sep 22.

Department of Chemical Engineering, Al-Balqa Applied University, Salt, Jordan.

Jordan relies heavily on reservoirs building and development to cope with water supply challenges, where monitoring and assessment of reservoir water quality are critically important for the sustainable use of these water supplies. Mujib Dam is an important water supply source in central western Jordan. Evaluation of water quality parameters and their spatial distributions (vertical and horizontal) showed near-neutral pH values with nearly similar values from surface to bottom. The vertical profile of DO and TDS in the dammed reservoir showed slight decreasing trends with increasing depth. Although Ca, Mg, Na, and K concentrations varied slightly with depths, their variations showed no trends. Similarly, the vertical and horizontal distribution patterns of Cl, SO, HCO, NO, and PO in Mujib reservoir water showed insignificant variations in surface water layer and relatively unchanged values or decreasing trends through the water column. Higher values of TN have been observed, especially in the western part, suggesting that agricultural activities and livestock farming in the upstream catchment are impacting water quality. Results revealed that weathering and dissolution of rocks are the major source of water chemistry. The majority of trace metal levels (Cd, Cr, Cu, Fe, Mn, Pb, Zn, Co, Ni, Sr, and B) in water showed relatively similar surface and bottom values. The concentrations of COD and BOD in surface water were relatively low with higher concentrations observed in the northwestern corner, coincided with higher levels of chlorophyll a. The average ratio of TN to TP in surface water suggests that phosphorus is the limiting factor for the algal blooms, whereas the average chlorophyll a level in surface water indicates oligo-mesotrophic water.
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http://dx.doi.org/10.1007/s10661-018-6976-9DOI Listing
September 2018

Characteristics and quality of reservoir sediments, Mujib Dam, Central Jordan, as a case study.

Environ Monit Assess 2017 Apr 7;189(4):143. Epub 2017 Mar 7.

Department of Biological Sciences, Faculty of Science, Yarmouk University, Irbid, 21163, Jordan.

This paper focuses on characterizing the current status of physiochemical properties of Mujib Dam sediments. Five types of granulometric textural facies were observed for the bottom sediments of Mujib reservoir bed; these are clayey facies, clayey-silt facies, sand-silt-clay facies, sand facies, and granule facies. This average grain size will likely play a vital role in adsorption-desorption of the majority trace metals to the reservoir lake. Other sediment parameters including the total averages were 5.9% (total organic matter (TOM)), 7.5 (pH), 25.8% (CaCO), and 88.0 meq/100 g (cation exchange capacity), with dominant mineralogical constituents of quartz, calcite, dolomite, and minor feldspar and with variability in clay mineral types. The vast majority of trace metals in sediment exhibited values in the range or near the upper limit of the normal worldwide soil ranges. TOM and grain size of sediment are major factors governing the trace metal concentrations. The calculated geoaccumulation index (I ) and enrichment factor (EF) of metals in sediments of Mujib Dam were ranked as follows: cadmium (Cd) > copper (Cu) > zinc (Zn) > lead (Pb) > cobalt (Co) > iron (Fe) > chromium (Cr) > nickel (Ni) > manganese (Mn) > Sr based on the I and Cd > Zn > Pb > Co > Cr > Cu > Sr > Ni > Mn according to the EF values. The estimated percentage loss in volumetric capacity of the reservoir due to sedimentation was 1.55% per year, indicating that the sediment currently occupied 18.63% of the original reservoir storage capacity. The maximum life span of reservoir is about 64.46 years.
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http://dx.doi.org/10.1007/s10661-017-5836-3DOI Listing
April 2017

Effects of pollution on the geochemical properties of marine sediments across the fringing reef of Aqaba, Red Sea.

Mar Pollut Bull 2016 Sep 27;110(1):546-554. Epub 2016 May 27.

Department of Earth and Environmental Sciences, Faculty of Science, Yarmouk University, Irbid 21163, Jordan.

The Gulf of Aqaba is of significant strategic and economic value to all gulf-bordering states, particularly to Jordan, where it provides Jordan with its only marine outlet. The Gulf is subject to a variety of impacts posing imminent ecological risk to its unique marine ecosystem. We attempted to investigate the status of metal pollution in the coastal sediments of the Jordanian Gulf of Aqaba. The distribution of Cd, Cr, Zn, Cu, Pb, Al, Fe, and Mn concentrations were determined in trapped and bottom-surface sediments at three selected sites at different depths. In addition, monthly sedimentation rates at varying water depths were also estimated at each sampling site using sediment traps. The high concentrations of Cd, Cr, Zn were recorded at the Phosphate Loading Birth (PLB) site followed by the Industrial Complex (IC) site indicating their dominant anthropogenic source (i.e., the contribution of industrial activities). However, Fe, Al, and Mn contents were related to inputs from the terrigenous (crustal) origin. Except for Al, Fe and Mn at the PLB site, the concentrations of metals exhibited a decreasing trend with increasing water depth (distance from the shoreline). The PLB site also showed the highest sedimentation rate which decreased with increasing water depth. The Enrichment factors (EFs) showed that Cd was the most enriched element in the sediment (indicating that Cd pollution is widespread), whereas the least enriched metal in sediments was Cu. EF values suggested that the coastal area is impacted by a combination of human and natural sources of metals, where the anthropogenic sources are intense in the PLB site (north of Gulf of Aqaba). The MSS area is potentially the least polluted, consistent with being a marine reserve. The IC sediments have been found to be impacted by human activities but less intensely compared to the PLB area. These results suggested that there are two sources of metals in sediments; the primary source is likely closer to PLB, while the secondary is nearby the IC.
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http://dx.doi.org/10.1016/j.marpolbul.2016.05.038DOI Listing
September 2016

Spatial distribution and pollution assessment of trace metals in surface sediments of Ziqlab Reservoir, Jordan.

Environ Monit Assess 2015 Feb 30;187(2):32. Epub 2015 Jan 30.

Department of Earth and Environmental Sciences, Yarmouk University, Irbid, 21163, Jordan,

Surface sediment samples were collected from Ziqlab dam in northwestern Jordan to investigate the spatial distribution of selected trace metals and assess their pollution levels. The results showed that the concentrations of Pb, Cd, and Zn exceeded the environmental background values. Cd, Ni, and Cr contents were higher than the threshold effect level (TEL) in 63, 83, and 60 % of the reservoir sediments, respectively; whereas Pb, Zn, and Cu were less than the TEL limit. The concentrations of trace metals in reservoir sediment varied spatially, but their variations showed similar trends. Elevated levels of metals observed in the western part (adjacent to the dam wall) were coincided with higher contents of clay-silt fraction and total organic matters. Multivariate analysis indicated that Pb, Co, and Mn may be related to the lithologic component and/or the application of agrochemicals in the upstream agricultural farms. However, Cd and Zn concentrations were probably elevated due to inputs from agricultural sources, including fertilizers. Evaluation of contamination levels by the Sediment Quality Guidelines of the US-EPA, revealed that sediments were non-polluted to moderately polluted with Pb, Cu, Zn, and Cr, but non-polluted to moderately to heavily polluted with Ni and non-polluted with Mn. The geoaccumulation index showed that Ziqlab sediments were unpolluted with Pb, Cu, Zn, Ni, Cr, Co, and Mn, but unpolluted to moderately polluted with Cd. The high enrichment values for Cd and Pb (>2) indicate their anthropogenic sources, whereas the remaining elements were of natural origins consistent with their low enrichment levels.
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http://dx.doi.org/10.1007/s10661-015-4289-9DOI Listing
February 2015

Atmospheric dry deposition of mineral dust to the Gulf of Aqaba, Red Sea: rate and trace elements.

Mar Pollut Bull 2015 Mar 18;92(1-2):252-258. Epub 2014 Dec 18.

Dept. of Earth and Environmental Sciences, Faculty of Science, Yarmouk University, Irbid 21163, Jordan.

Atmospheric dry deposition to the Gulf of Aqaba (GoA) is particularly a significant source of trace elements. Amid desert regions, the Gulf receives high fluxes of mineral dust with an average rate of 34.68 g/m(2)/year measured in 2012. Patterns of dry deposition showed seasonal fluxes with highest rates observed in summer and lowest in winter. The observed variations were attributed to wind direction, timing of deposition and sources of dust. The average dry fluxes of Al, Fe, Mn, Cr, Cd, Cu, Pb and Zn were 551, 440, 10.29, 1.42, 0.04, 0.68, 1.42 and 4.02 mg/m(2)/year, respectively. While the dry deposition fluxes were enriched in Cd, Cu, Pb and Zn indicating their dominant anthropogenic sources, they appeared to be less influenced compared to the neighboring Mediterranean area and other industrial countries, but were similar to or slightly higher than those in remote areas. The enrichment values for Fe and Mn were low, consistent with their crustal origin. The fluxes of all elements suggested the impacts of both crustal (due to climate change) and anthropogenic sources became stronger in this region. The Sahara dust was probably a minor contributor to dry deposition in the GoA.
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http://dx.doi.org/10.1016/j.marpolbul.2014.11.047DOI Listing
March 2015

Status of trace metals in surface seawater of the Gulf of Aqaba, Saudi Arabia.

Mar Pollut Bull 2014 Sep 7;86(1-2):582-590. Epub 2014 Aug 7.

Department of Geology, Taibah University, PO Box 30002, Madinah 41477, Saudi Arabia.

The Gulf of Aqaba (GoA) is of significant ecological value with unique ecosystems that host one of the most diverse coral communities in the world. However, these marine environments and biodiversity have been threatened by growing human activities. We investigated the levels and distributions of trace metals in surface seawater across the eastern coast of the Saudi GoA. Zn, Cu, Fe, B and Se in addition to total dissolved solids and seawater temperature exhibited decreasing trends northwards. While Mn, Cd, As and Pb showed higher average levels in the northern GoA. Metal input in waters is dependent on the adjacent geologic materials. The spatial variability of metals in water is also related to wave action, prevailing wind direction, and atmospheric dry deposition from adjacent arid lands. Also, water discharged from thermal desalination plants, mineral dust from fertilizer and cement factories are potential contributors of metals to seawater water, particularly, in the northern GoA.
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http://dx.doi.org/10.1016/j.marpolbul.2014.05.060DOI Listing
September 2014

Trend analysis in water quality of Al-Wehda Dam, north of Jordan.

Authors:
Ahmed A Al-Taani

Environ Monit Assess 2014 Oct 11;186(10):6223-39. Epub 2014 Jun 11.

UNESCO Chair for Desert Studies and Desertification Control, Yarmouk University, Irbid, 21163, Jordan,

Temporal status and trends in water quality of Al-Wehda Dam, Jordan, from 2006 to 2012 indicate that the dam is subject to a combination of impacts from rainstorm and agricultural runoffs. It also revealed that mineral dissolution, sediment load, rainfall events, evaporation, and water-level fluctuation are the major contributors to variations in water quality. The water chemistry of the impounded Al-Wehda Reservoir showed that Na, Ca, Mg, HCO₃, and Cl are the principal ions, reflecting the dominance of carbonate weathering, with some contribution of silicates. The pH values showed a cyclic pattern with highest values observed in the spring seasons. Total dissolved solids (TDS), Ca, Mg, and HCO₃ are primarily related to leaching and evaporation, with elevated levels that occurred in the rainy winter months. In contrast, seasonal patterns in Na, K, Cl, and NH₄-N contents showed decreased values in winter. Peaks in NO₃-N observed in winter are strongly associated with agricultural runoff. Fluctuations in chlorophyll-a level were coincided with low ratio of total nitrogen (TN) to total phosphorus (TP). Seasonal variations in organic matter content were also apparent, with peaks that generally occurred in spring through early fall corresponding with high algal growth. On an annual basis, the vast majority of water quality data have generally declined, particularly, in 2011. However, it is not clear whether these decreases are related to change in management practices within the Yarmouk basin, or protective measures have been implemented. Comparison of in-lake and post-dam water quality from 2009 to 2011 showed variation in concentrations, where Ca, HCO₃, NO₃-N, Mg, and TDS showed relatively greater post-dam values than in-lake water, whereas pH, Na, Cl, K, COD, BOD₅, and chlorophyll-a were consistently lower in post-dam water. This comparison emphasizes the importance of self-purification capacity of Al-Wehda Dam in reducing some contaminants.
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http://dx.doi.org/10.1007/s10661-014-3850-2DOI Listing
October 2014

Investigation of desert subsoil nitrate in Northeastern Badia of Jordan.

Sci Total Environ 2013 Jan 22;442:111-5. Epub 2012 Nov 22.

Desert Studies and Desertification Control, Yarmouk University, Irbid 21163, Jordan.

High levels of naturally occurring nitrate were observed under desert pavement surfaces in NE Badia of Jordan. The subsoil nitrate inventory varies from about 24,351 to 28,853 kg NO(3)(-)/ha to a depth of 60 cm which is more than two times greater than nitrate in nonpavement soils, although both soils occurred within similar landscape and microclimate conditions. The results indicated that pavement particle size and cover percent are the primary factors contributing to the observed variations in nitrate accumulation. Desert pavement soils fully covered with fine clasts showed higher nitrate concentrations compared to soils moderately covered with coarse-grained pavements. The results also showed that high levels of nitrate were generally reached between 20 and 30 cm depth before the concentrations decreased. Chloride showed distribution profiles similar to those of nitrate. No observable difference was observed in nitrate level under desert pavement with abundant lichens compared to non-lichen pavement surface.
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http://dx.doi.org/10.1016/j.scitotenv.2012.10.018DOI Listing
January 2013