Impact of Drainage Effluents on The Water Quality of Abu-Qir Bay , Alexandria , Egypt

Abu-Qir Bay, a semi-enclosed heavily polluted Mediterranean basin in Egypt, is receiving huge amounts of untreated sewage, industrial, and agricultural waste waters via three land-based sources: Tabia pumping station [TPS], Outlet of lake Edku [Boughaz El-Maadiya], and Rosseta mouth of River Nile. In order to mitigate and control the impact of pollution on coastal and marine resources, it is essential that the type and load of pollutants be identified. So water samples were collected from sixteen stations covering Abu-Qir Bay, seven stations covering Lake Edku, one sample from El-Ammia Drain [TPS], and eight samples from the drains affected or entering lake Edku during April and May 2005. The hydrochemical parameters, i.e., water temperature, chlorosity, salinity, dissolved oxygen pH, total suspended matter, oxidizable organic matter, calcium, and magnesium as well as nutrient salts: the nitrogen forms [ammonium, nitrite, and nitrate], the reactive phosphate and reactive silicate were investigated.

Bull High Inst Public Health Vol.37 No. 1 [2007] and Lake Edku.The pollution input in the bay from these two main sources is as follows:

RESULTS AND DISCUSSION:
The results of the studied variables in this paper are recorded in tables 1 and 2 and represented graphically in figures 3-7.

I-Physico-chemical characteristics:
The water temperature at Abu-Qir Bay and Lake Edku exhibited higher values than those of the connected drains.However, the higher temperature values, reaching the maximum of 29.5 °C, were observed at the bay.In the drains waters of Lake Edku, the temperature values ranged between 17.0 and

II. Nutrient Salts
The studied nutrients in Abu-Qir Bay, Lake Edku, and their related drains are: nitrites, nitrates, ammonia, phosphates, and silicated.The data obtained in this study are recorded in Tables 1 and 2 a) El-Tabia Pumping Station [TPS], in the south-east part of the bay with about 2X10 6 m³ day -¹ discharging capacity.It was estimated that about 730 X 10 6 m³ of waste waters are discharged annually through this point source, in channel [El-Ammia] of 200 m length.These wastes are mainly industrial, with some agricultural and domestic contribution.b) Lake Edku [31.27°N and 30.15°E].It covers an area of 126 km 2 with a mean depth of 1 m [Fig.2].This coastal lagoon is almost an agricultural drain.Through its connection with the bay [Boughaz El-Maadiya] about 390 x 10 6 m³ of agricultural waste.Water is charged annually into Abu-Qir Bay.Two main drains discharge their water into Lake Edku.The first drain namely Kom Belag receives its water from three sub drains; Bosily, Edku, and El-Khairy where they are connected at about 3 km to the east of the lake.The second main drain is Bersik Drain which outlets its water at the southern central part of the lake.MATERIAL AND METHODS: During spring 2005, four field trips were performed.A total of 16 stations allover Abu-Qir Bay were selected to represent different locations situated under the direct effect of land-based sources and some other sites [Fig.1].Seven sampling stations were selected at lake Edku and eight ones from the drains affecting the lake [Fig.2].Moreover, one water sample was collected from El-Ammia Drain representing the effluent of TPS.

Figure 2 :
Figure 2: The location map of sampling stations in Lake Edku and its Drains.
18.0°C, while El-Ammia Drain water recorded 19.5 o C. The present data display that all the pHvalues were on the slight alkaline side and lower than that of the open sea.The pHvalues of Abu-Qir Bay [ranged from 7.25-8.35]were slightly lower than that recorded for water of Lake Edku [8.1-8.5] and the drains [7.77-9.2].Salinity and chorosity showed the some trend at Abu-Qir Bay, Lake Edku, and their related drains [Figs.3, 6, and 7].El-Ammia Drain [TPS] exhibited of course an extraordinary low absolute salinity [1.56‰] and chlorosity [0.48 g/L].At Abu-Qir Bay, salinity distributions [Fig.3] reflect the influence of the drainage outflows mainly in the northwestern part of the bay [sts.

Figure 6 :
Figure 6: Physicochemical parameters recorded in Lake Edku and its related Drains.

Figure 7 :Figure 8 :
Figure 7: Spatial variation in some major ions concentration in Lake Edku and its related Drains.