Hussain Alfaifi

Metal pollution in Al-Khobar seawater, Arabian Gulf, Saudi Arabia

In order to assess heavy metals pollution along the Al-Khobar coastline, 30 seawater samples and 15 sediment ones were collected for Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Hg and Pb analysis by Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). The analysis indicated a southward decreasing pattern in most heavy metal concentrations and the average values of Zn, Fe, Mn, Cu, As and Cr were higher than the ones reported from some worldwide seas and gulfs. Most of the highest levels were recorded within the bays and were related with in situ under sediments especially that composed of clays and very fine sands, and in localities characterized with anthropogenic activities like landfilling, desalination plants, fishing boats, oil spills and solid rubbish. The results of the present study provide useful background for further marine investigation and management in the Arabian Gulf region.

Geotechnical investigation of the El-Elb dam site, northwest Riyadh, Saudi Arabia, using 2D resistivity and ground-penetrating radar techniques

In the present study, the existence of cavities, voids, and fractures was verified at the site of the El-Elb Dam, which is located to the northwest of Riyadh City across Wadi Hanifa, using 2D electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) techniques. For this purpose, four ERT profiles were measured on the downstream side of the El-Elb Dam using the Syscal Pro Switch-72 resistivity meter. In addition, a GPR survey using a 400-MHz antenna and a SIR-3000 instrument was conducted along five profiles above the stilling basins on the downstream side of the dam and one radar profile was measured outside the stilling basins area across the course of the wadi. The resultant geophysical data were interpreted with the aid of information from a field-based structural and stratigraphic evaluation of the outcropped bedrock on the banks of the wadi course. The analysis of the inverted ERT and filtered radar sections revealed several resistivity and electromagnetic reflection anomalies that are identified laterally and vertically across the measured sections. These anomalies indicate the presence of fractures and karst features affected the limestone bedrock in the dam site. These near-surface karstified and fractured strata represent a critical hazard to the structural safety of the dam.

Spatial distribution and metal contamination in the coastal sediments of Al-Khafji area, Arabian Gulf, Saudi Arabia

To document the spatial distribution and metal contamination in the coastal sediments of the Al-Khafji area in the northern part of the Saudi Arabian Gulf, 27 samples were collected for Al, V, Cr, Mn, Cu, Zn, Cd, Pb, Hg, Sr, As, Fe, Co, and Ni analysis using inductively coupled plasma-mass spectrometer (ICP-MS). The results revealed the following descending order of the metal concentrations: Sr > Fe > Al > As > Mn > Ni > V > Zn > Cr > Cu > Pb > Co > Hg > Cd. Average levels of enrichment factor of Sr, As, Hg, Cd, Ni, V, Cu, Co, and Pb were higher than 2 (218.10, 128.50, 80.94, 41.50, 12.31, 5.66, 2.95, 2.90, and 2.85, respectively) and that means the anthropogenic sources of these metals, while Al, Zn, Cr and Mn have enrichment factor less than 2, which implies natural sources. Average values of Sr, Hg, Cd, Cr, Ni, and As in the coastal sediments of Al-Khafji area were mostly higher than the values recorded from the background shale and earth crust and from those results along coasts of the Caspian Sea and the Mediterranean Sea. The highest levels of Cu in the northern part of the studied coastline might be due to Al-Khafji desalination plant, while levels of Al, Ni, Cr, Fe, Mn, Pb, and Zn in the central part may be a result of landfilling and industrial sewage. The highest levels of As, Cd, Co, Cu, Hg, and V in the southern part seem to be due to oil pollutants from Khafji Joint Operations (KJO). The higher values of Sr in the studied sediments in general and particularly in locality 7 could relate to the hypersalinity and aragonitic composition of the scleractinian corals abundant in that area.

Hydrochemical characteristics and evaluation of the granite aquifer in the Alwadeen area, southwest Saudi Arabia

This study was carried out in the Alwadeen area of Khamis Mushayt district of southwestern Saudi Arabia to evaluate the hydrochemical characteristics of the shallow hard rock aquifers. These hard rock aquifers mostly comprise granites and contain significant quantities of groundwater that complement the available groundwater from the unconsolidated alluvial sediments in the nearby wadis. The field investigation indicates two main fracture sets which intersect each other and are oriented in the west-northwest and east-west directions. The granitic rocks in the area are intruded by coarse-grained and quartz-rich monzogranite and pegmatite veins. Hydrogeologically, the fracture systems are important since they facilitate the groundwater storage and assume the transmissive function during times of groundwater abstraction. Given the fact that groundwater in the fractured rock aquifers generally occurs at shallow depths, it may be exposed to contamination from surface and/or near-surface sources, and it is therefore important to evaluate its quality. To this end, a hydrochemical analysis was carried out on six groundwater samples collected from the area. The hydrochemistry revealed that the groundwater is fairly fresh, and facies analysis reveals mixed Na-Cl and Ca-Mg-Cl-SO4 types. Overall, the results reveal that the groundwater is saturated with calcite and dolomite, but unsaturated with gypsum and halite. The degree of salinity increases in the direction of the groundwater flow due to increased rock-water interaction.

Spatial distribution and ecological risk assessment of the coastal surface sediments from the Red Sea, northwest Saudi Arabia

To assess the spatial distribution and ecological risk assessment along the Red Sea coast, Saudi Arabia, 30 samples were collected for aluminum, chromium, copper, zinc, cadmium, lead, mercury, iron, cobalt, nickel and organic matter analysis. The descending order of metal concentrations was Al > Fe > Cr > Cu > Zn > Ni > Co > Pb > Hg > Cd. Average values of enrichment factor of Hg, Cd, Cu, Co, Cr, Ni, Pb and Zn were higher than 2 (209.50, 25.52, 20.36, 9.62, 7.28, 6.52, 6.21 and 6.07 respectively), which means anthropogenic sources of these metals. The average levels most of the studied metals were lower than those of the background shale and the earth crust and those recorded along most worldwide coasts, while the average values of zinc, copper, cobalt and nickel were higher than the values recorded from the Red Sea coast, the Gulf of Aqaba and some Caspian Sea coasts. The Duba bulk plant-Saudi Aramco, Duba refinery station and the tourist resort were the possible anthropogenic sources of pollutants in the southern part of the study area; and the landfilling, cement factory and Duba port and shipment operations in the central part, while the landfilling resulting from construction of the green Duba power plant and crowded fish boats were the possible sources in the northern part.

Assessment of sediment quality using different pollution indicators and statistical analyses, Hurghada area, Red Sea coast, Egypt

Thirty bottom sediment samples were collected from northern Hurghada coast, Red Sea, Egypt to evaluate the level of anthropogenic pollutants, using enrichment factor (EF), potential ecological risk index (PERI), soil pollution index (SPI), potential contamination index (Cp) and multivariate statistical analysis (correlation analysis, principal component analysis, and hierarchical cluster analysis). Fe, Mn, Zn, Pb, Ni, Cu, Co and Cd were analyzed by Atomic Absorption Spectrophotometer. Results indicated that the average values of Pb and Cd were greater than the ones recorded from many other worldwide coastal areas. The studied sediments are extremely severe enrichment with Pb and Cd (EF > 50), severe enrichment with Zn (EF = 10-25), very high risk with Cd (PERI ≥ 320), high risk with Pb (160 ≤ PERI ˂ 320), highly contaminated with Pb (SPI > 3), a severe contamination with Pb (Cp > 3). The accumulation of pollutants is associated with the muddy and fine sediment; especially the studied area is a semi-closed bay, characterized by long time of water retention. Possible sources of metals pollution in the studied area are shipment operations and anticorrosive and antifouling paints, dredging and land filling, municipal wastewater from tourist centers and fishermen cargo boats.