Environmental Effect of Using Polluted Water in New/Old Fish Farms

Abstract

One of the most dangerous hazards affecting the environment situation in arid and semiarid countries like Egypt is the water and soil pollution. Due to the lack of fresh water for irrigation, countries in arid and semi arid areas are forced to use marginal waters for irrigation and raising fish. The effect of using such kind of low quality water is rather dangerous on the environmental situation. Besides, countries like Egypt are facing great problems to get rid of untreated waste water and industrial disposal in addition to drainage water. The spill of such kind of waters in drains and lakes will cause great problems to the eco-system and environment in general. What will make the problem more complicated is the use of these waters for irrigation or raising fish due to lack of fresh waters. The using of polluted water in fish farms has a very dangerous environmental effect on soil and ground water. The water level in fish farms is higher than the original land level. Consequently, water flows from fish farms to the adjacent land and cause problems if the water was polluted. Bahr El-Baqar drain is considered as one of the most polluted drains in Egypt (Abdel-Shafy & Aly 2002). It receives and carries the greatest part of wastewater (about 3 BCM/year) into Lake Manzala through a very densely populated area of the Eastern Delta passing through four highly populated Governorates. Unfortunately, at the last decades, great areas on both sides of the drain were using its polluted water for irrigation and raising fish. As a polluted drain with high risk to the surrounding environment, Bahr El Baqar has received considerable concern by many scientists. Ali et al. (1993), Abdel-Azeem et al. (2007) studied the effect of prolonged use of drain water for irrigation on the total heavy metals content of south Port-Said city soils. They found that using such kind of water will cause high concentration of heavy metals in soil and plants roots and shots. Water quality, chemical composition, and hazardous effects on Lake Manzala water and living organisms caused by Bahr El-Baqar drain water has also been studied by several investigators like: Rashed & Holmes (1984), Khalil (1985) and Ezzat (1989). Special attention has been paid to the effect of environmental pollution from microbiological and toxicological points of view (Zaki 1994). Fish farms located on both sides of the Bahr El-Baqar drain are using the polluted water for rising fish since long time ago. Furthermore, many agricultural lands located in these areas are also using such kind of water for irrigation. The hazardous of such kind of water on