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Wadi El Raiyan is a great depression located southwest of Cairo in the western desert of Egypt, one of the most arid regions of the world. In 1973, Wadi El Raiyan was connected with the agricultural wastewater drainage system of the El Faiyum province to provide a reservoir for the wastewater that exceeded the capacity of Lake Qarun north of the province. Pollutants from agricultural waste including pesticides and fertilizers as well as other effluents of industrial activities and runoffs certainly will pass into the biotic elements of the ecosystem. This report presents the status of inorganic pollutants including anions, cations, and trace metals in the two lakes and the surrounding springs of Wadi El Raiyan using ion chromatography, ion-selective electrodes, and inductively coupled plasma emission spectroscopy. The report also includes the levels of selected metals in the vegetation community of the area. The result of this investigation revealed a great improvement in water quality of the Wadi El Raiyan lakes compared to 1988 report by Saleh et al. Mercury was not detected in any of the samples and the level of lead was significantly reduced. Cadmium levels were much higher than those seen earlier. The higher level of cadmium might be used as an indicator to track the contamination of water by human waste. Concentrations of common anions were not significantly different from those reported earlier. However, an increase in the level of cyanide was observed. Levels of heavy metals in vegetation around the lakes were also found to be lower than previously reported., (Copyright 2000 Academic Press.)

Trace metal pollutants in the surface water of the Houston Ship Channel were determined using inductively coupled plasma/mass spectrometry (ICP/MS). Metal concentrations varied according to sampling sites. Barium, cobalt, chromium, molybdenum, silver, beryllium, antimony, lead, and mercury concentrations were relatively similar throughout the channel averaging 83.25, 0.55, 6. 31, 6.66, 0.02, 0.017, 3.61, 0.68, and 0.055 microg/L, respectively. Titanium, manganese, copper, zinc, nickel, and selenium concentrations were found to be higher at stations closer to the Galveston Bay (as the water is turning from relatively fresh water to sea water) with concentration ranges of 102.5-351.7, 0.3-25, 0. 3-25, 30-280, 16-77, 6.2-26.5, and 0.0-6.2 microg/L, respectively. Aluminum was found to be much higher at the Buffalo Bayou station (341 microg/L) followed by the San Jacinto station (104 microg/L) with an average of 42 microg/L in the other two stations. Vanadium was found to be unusually high at the Washburn Tunnel station (116 microg/L) and at much lower concentrations in the other three stations, averaging 6.5 microg/L. Iron was also higher at the Buffalo Bayou station (143 microg/L) but was absent at the Lynchburg Ferries station. Arsenic was not found at the Lynchburg and San Jacinto stations. However, arsenic had similar concentrations of 1. 983 and 1.835 microg/L at Buffalo Bayou and Washburn Tunnel, respectively. Cadmium was higher at the Lynchburg Ferries station (3. 3 microg/L) and ranged from 0.3 to 0.96 microg/L in the other locations. Thallium was not found in any of the stations., (Copyright 1999 Academic Press.)