Evaluation of Water Quality for some Drains in Dakahlia Governorate, Egypt

Abstract

Fresh water resources are limited to meet annual needs of irrigation water for agricultural production in Egypt. So drains water can be used to recover this gab and quality of this water should be studied before using it. Dakahlia Governorate is located in the northeastern of the Nile Delta. It is located near the ends of canals and agricultural drains. These agricultural drains carrying sewage and industrial waste waters (treated and untreated) .The drains water normally used to irrigate some lands near the ends of the irrigation canals. In this study, three agricultural drains were selected taking in consideration its water are used to irrigate farm land. The selected drains are drain No.1, drain No.2 and EL-Mansoura Al-Mustajad drain. Water quality of these drains were studied during winter and summer seasons of 2014. 14 water samples were taken during this period in order to evaluate water quality for irrigation. The obtained results indicated that pH values were within the permissible limits for irrigation even they were higher in winter than in summer season. While EC and , SAR values were slight to moderate. NO3-N values were slight to moderate in all water samples except for water samples (No. 6 and 7) in EL-Mansoura Al-Mustajad drain. NH4-N values for all samples were in the accepted range according to FAO (1985) except for sample No. 7 at the end of EL-Mansoura Al-Mustajad drain which were sever according to FAO (Food and Agriculture Organization) standards. The results indicated also that COD (Chemical Oxygen Demand) and BOD (Biological Oxygen Demand) levels were within the maximum limits for water irrigation except COD values of water samples No. 1 in summer and No. 3 in winter and summer. The BOD values were in the same trend for water irrigation according to Egyptian and U.S.EPA (2004) (United States Environmental Protection Agency) standards. In general, the values were higher in winter than in summer season. The heavy metals values in summer season were higher than in winter one. Mostly , the heavy metals content of the drains was arranged in the following descending order: Ni> Pb> Cd according to NAS/NAE, (1972) (National Academy of Sciences / National Academy of Engineering) and FAO (1985). The results indicated that heavy metals contents were within the permissible limits for irrigation in most sites for lead (Pb) except for water samples No. 7, they were in the maximum limits (more than 5 ppm), While cadmium and nickel values were within the maximum limits for irrigation in water samples except water samples (No. 1 and 3 in winter and summer and No. 5 in winter). The obtained data showed that Ni values were within the maximum limits for irrigation except water samples (No. 1 , 3 and 5 in winter and summer) . In general, the EC ,SAR, NO3 -N , NH4-N , COD , BOD , heavy metals (Pb, Ni and Cd) values at the beginning of the drains were lower than at the end of the drains in the studied area in the three drains . The evaluation of drains are ranged from slightly to moderately suitable for all stu...