Abstract
El-Raiyan lakes were created as a reservoir for agricultural drainage wastewater in the Western Desert of Egypt. The project was started in 1968 and has been operating since 1973. Physical and chemical properties of water from 17 sampling stations in the lakes and in the springs of the surrounding deserts were monitored every three months during the years 1984 and 1985. Concentrations of metals (cadmium, copper, iron, lead, manganese , mercury, selenium, and zinc) and or inorganic anions (sulfate, sulfite, sulfide, nitrate, nitrite, ammonia, cyanide, thiocyanate, halogens, carbonate, silicate, and phosphate) were generally lower than those reported for other lakes of Egypt which are used as wastewater reservoirs. The concentrations of metals and inorganic anions in water varied according to the distance from the origin of the lakes, depth, and seasons of the year. Concentrations of heavy metals in fish and in selected wildlife fauna and flora of the surrounding deserts were also determined. Animals living near the lakes had much higher concentration of heavy metals, particularly lead, mercury, and cadmium, than animals of the same species collected further away from the lakes. High rate of evaporation may cause concentrations of heavy metals to soon reach dangerous levels. This may effect the utilization of the lake for fish production and may also pollute groundwater of the nearby springs and be transferred through the food chain to wildlife of the area. The use of biological filters and/or growing grass on the sand dunes may be used to clean up heavy metals from the water. (Mertz-PTT)