| Abstrakt: |
Wadi El-Rayan is a natural protected area in Egypt. Wadi El-Rayan depression (southwest of Cairo in the western desert of Egypt) holds two man-made lakes which receive the wastewater drainage of El Fayoum Province. The present study aimed to investigate the effect of pollution in Wadi El-Rayan Lakes on Tilapia spp. Water and fish samples were collected from Wadi El-Rayan Lakes during winter 2014 to estimate heavy metals, pesticides and indicators of microbial pollution. Moreover, the effect of pollutants and degraded water quality on the physiological and biochemical parameters, the histological structures of the organs (muscle, liver and kidney), in addition to the impact on the fish quality were studied. The second lake of Wadi El-Rayan Lakes and El-Wadi Drain showed that Cd recorded the lowest concentrations (2.0-6.0µg/l), while Fe recorded the highest concentrations (117.96-298.4µg/l), similarly, in the first Lake, Fe recorded the highest concentrations (154.8-460.8µg/l).Metal concentrations in Tilapia spp. from the first and second lake of Wadi El-Rayan Lakes followed an abundance of: Cd Tilapia spp. from the first lake. A wide variety of organophosphorus pesticides, including Atrazine, Simazine, Propazine, Simetryne, Ametryne, Prometryne, Terbutryne and Dimethoate were detected in the water of El-Wadi Drain and station 1 (discharge point of El-Wadi Drain) in Wadi El-Rayan Lakes. Also, the organochlorine pesticide Gamma-BHC was detected in the water of El-Wadi Drain and stations 1,2,3,5&7 in Wadi El-Rayan Lakes. Tilapia spp. from the first lake of Wadi El-Rayan Lakes showed the presence of a wide variety of organophosphorus and organochlorine pesticide, however, the fish samples from the second lake showed the presence of Malathion, Parathion methyl and Gamma-BHC only. The indicator bacteria in Wadi El-Raiyan Lakes waters exceeded the acceptable values, except at stations (3, 4, 6, 7 and 8). Also, El-Wadi Drain water exceeded the acceptable values for drainage water discharged into the lake. The bacterial load values were 2.11 x 105 cfu/g and 2.02 x 105 cfu/g in Tilapia spp. from the eastern and middle parts of the first lake of Wadi El-Rayan Lakes, respectively and 1.64x 105 cfu/g in Tilapia spp. from the second lake. The levels of plasma glucose, total proteins, albumin, total lipids, triglycerides, urea, uric acid and creatinine showed a general trend of increase in Tilapia spp. from Wadi El-Rayan Lakes. Similarly, GOT, GPT, ALP and LDH activities exhibited high increase in the fish from the lakes. Several histological alterations were observed in the muscles, liver and kidneys of Tilapia spp. from Wadi El-Rayan Lakes. In conclusion, the environmental pollution in Wadi El-Rayan Lakes induced physiological, biochemical and histopathological alterations in Tilapia spp. [ABSTRACT FROM AUTHOR] |
