A physical and chemical analysis of Egypt's Wadi El-Raiyan man made lakes
Titel:
A physical and chemical analysis of Egypt's Wadi El-Raiyan man made lakes
Auteur:
Wilson, Bobby L. Saleh, Mahmoud A.
Verschenen in:
Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering
Paginering:
Jaargang 25 (1990) nr. 7 pagina's 775-784
Jaar:
1990-10
Inhoud:
Detailed physical and chemical analyses of selected sites in and around two Wadi El-Raiyan lakes in the El-Faiyum Province of Egypt were conducted over a two-year period. The man-made lakes were created in early 1973 as a reservoir for agricultural irrigation drainage water. The water created a surface area of about 200 square kilometers in a depressed area in the western desert of Egypt, and the evaporation coupled with very low precipitation has led to a rapid increase in salinity and trace metal content. The salinity was 0.5 g/L (ppt) at the water inputs the lakes coming from the tunnel of Wadi El-Raiyan and then increased gradually to about 1.0 ppt in the first lake and to an average of 2.0 in the second lake. Salinity of the water springs were constant, however, salinity of the seepage area increased dramatically to 7 ppt. Water pH was very much the same throughout the lakes being neutral to slightly basic (7.8 - 8.8). Heavy metals concentration in water was very low, much below the recommended levels for general uses and below the permissible values for public water supplies. Dissolved oxygen in the lakes varied from 6.2 to 11 mg/L (ppm) depending on station locations and depth. Ammonium nitrogen varied from 0.02 to 0.05 ppm. The dissolved oxygen and ammonium concentration in water were found to be suitable for fish production. Therefore, the water may be classified as salmonoid water. Nitrite, sulfide, phosphate and thiocyanate concentration was very low, halides concentration was moderately high and sulfate concentration was very high ranged from 515 to 1285 ppm. No arsenates were detected in any of the samples.
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