In the last three decades, the industrial and human activities in the coastal area of Saudi Arabia have increased dramatically and resulted in the continuous invasion of different types of pollutants including heavy metals. Seven sediment cores were collected from three major industrialized areas; Jeddah, Rabigh and Yanbu, along the coast of Saudi Arabia to determine the spatial and temporal distribution of metals and to assess the magnitude of pollution and their potential biological effects. Sediments were analyzed for texture, calcium carbonate contents, organic matter and metals (Al, Fe, Mn, Cd, Cr, Cu, Ni, Pb and Zn). Some metals like, Cr, Mn, Ni and Zn, were enriched in the upper 15 cm of core samples (recent deposition of sediments). Cadmium concentrations showed high fluctuations with depth and reverse pattern to that for Al, Fe and Mn which indicated land based sources of this element to the studied areas. Elevated concentrations of lead were recorded in the bottom layers of cores in Jeddah that indicated the most dramatic increase in usage of gasoline in early 1970s. The calculated contamination factors (CF's) were found in the following sequences: Cd > Pb > Ni > Cu > Zn > Cr > Mn for all studied areas. Results of Pollution Load Index (PLI) revealed that Jeddah is the most polluted area, followed by Rabigh while Yanbu is the least contaminated area. Except for Ni, the concentrations of most metals in the majority of sediment samples were believed to be safe for living organisms. As no data were available on the concentration of metals in core sediments in the coastal area of Saudi Arabia, the results of this study would serve as a baseline against which future anthropogenic effects can be assessed.

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In the light of progressive depletion of groundwater reservoir and water quality deterioration of the Wadi Marwani alluvial aquifer, an investigation on chemical data of dissolved major and minor constituents in 16 recent groundwater samples was performed. The main objective was the detection of processes responsible for the geochemical evolution and mineralization throughout the area. Wadi Marwani is one of the most important wadis in the central western part of Suadi Arabia to the northeast of Jeddah City. It is intensively inhabited during the last decenniums, leading to expansion of the residential and agricultural areas. The recharge rate of the shallow unconfined aquifer of Wadi Marwani was estimated to be 18% of the annual precipitation using the chloride mass-balance method. Groundwaters of the study area are characterized by the dominance of Ca + Mg over Na + K. HCO 3 was found to be the most dominant anion in the upstream and replaced by Cl towards downstream reflecting geochemical evolution along flow path and the influence of agricultural activities and residential areas. TDS is positively correlated with most of major ions, which suggested the impact of agricultural activities on groundwater chemistry through leaching of readily soluble salts from the soil zone. NO 3 and TDS showed similar trend which suggested leaching of nitrate fertilizers applied in the agricultural areas. Anomalously high nitrate concentration in few water samples is mainly attributed to leakage of domestic wastewater from the residential area that is very close to these wells. Fluoride concentration showed uniform spatial distribution, which revealed that it is mainly derived from dissolution of silicate minerals forming the aquifer matrix. Most of the groundwater samples are undersaturated with respect to the common carbonate and sulfate minerals, whereas oversaturated with respect to quartz and chalcedony.Groundwater quality assessment revealed that the groundwater can be safely used for drinking. However, further microbiological examination should be carried out where signs of sewage contamination were detected.

Abstract. The combined chemical composition, O and H isotopes, and the basic geologic setting of the geothermal system of the Gulf of Suez, Egypt have been investigated to evaluate the origin of the dissolved constituents and subsurface reservoir temperatures. Hydrochemical characterization of thermal waters discharged from springs and flowing artesian wells in the Gulf of Suez region show that there are two groups. One is Hammam Faroun thermal waters with salinity values exceeding 10,000 mg/l, discharge temperatures reach to 70ºC, and Na-Cl hydrochemical facies. The other group is thermal waters discharged at Hammam Mousa, Ain Sukhna, and shallow flowing artesian wells at Ayoun Mousa and Ras Sudr. They are characterized by salinity values less than 10,000 mg/l, discharge temperatures ranging from 32.5 to 72ºC and Na-Mg-Ca-Cl (Hammam Mousa), Na-Cl-SO 4 (Ain Sukhna), and Na-Ca-Cl (Ayoun Mousa-2 well and Ras Sudr-2 well) water types. Different graphical presentations using major and minor ions indicated that little mixing with sea water is probably a source of dissolved constituents. Water/rock interaction is also a major source for the dissolved constituents as revealed from Ca and HCO 3 enrichment of the thermal waters that is attributed to dissolution of carbonate minerals. Thermal waters from Hammam Faroun and Ras Sudr-2 well have the highest discharge temperatures and SiO 2 concentrations that indicate that ascending hot water at the Hammam Faroun area is slightly mixed with cold water. The thermal waters from the study area are depleted in 18 O and 2 H and fall on the Global Meteoric Water Line (GMWL) and below the local eastern Mediterranean Meteoric Water Line (MMWL) with d-excess values ranging between 3.42 and 10.6‰, which is similar to the groundwater of the Nubian aquifer in central Sinai and the Western Desert of Egypt and suggesting a common origin. This indicates that these waters are paleo-meteoric water which A.A. El-Fiky 72 recharged and flushed residual saline water in the Nubian aquifer under different climatic conditions than the modern ones. All thermal waters of the study area are undersaturated with respect to sulfate minerals (gypsum and anhydrite) and oversaturated or nearly in equilibrium with respect to aragonite, calcite and dolomite indicating that these minerals occur in the reservoir. All the thermal waters are oversaturated and nearly in equilibrium with quartz and chalcedony indicating equilibration with a sandstone aquifer free of gypsum and anhydrite with minor carbonate minerals. The subsurface reservoir temperatures were calculated using different solute geothermometers and gave temperatures ranging between 13.0 and 190.5ºC. Na/K and Na-K-Ca geothermometers gave the maximum reservoir temperatures (135-190.5ºC), whereas Na-K-Ca-Mg and Mg/Li geothermometers gave the lowest temperatures (13.0-45.9ºC). Quartz geothermometer gave the most reasonable subsurface temperatures (61.5-104.5ºC). The Hammam Faroun and Ras Sudr areas have the highest subsurface reservoir temperatures, which...

With the help of a SLERA, it was possible to indicate which class of chlorinated organic compounds is of highest concern to assess and to improve the environmental quality of the bay. Monitoring of organochlorines and chlorpyrifos would be needed to control the future trend of pollution.