Physicochemical properties of Manzala Lake, Egypt

Abstract

Physicochemical parameters such as temperature, total dissolved solid (TDS), pH, salinity, dissolved oxygen (DO), biological oxygen demand (BOD), permanganate index (PI), chloride and nutrient salts were measured in water samples, collected from 12 sites of Manzala Lake during winter and summer, 2015. A lot of fluctuations were observed in these parameters affected by the poor connection of water body of the lake and the diversity of the incoming flows. The pH values of water were alkaline throughout the lake and closely correlated with widely varied salinity and DO values. BOD increases in the south eastern-located sites affected mostly by Bahr El Baqur drain effluents especially during winter during the scheduled water block. PI was highly influenced by the agricultural and domestic waste effluents. Nutrients salts ranged between 5.47-249, 2.61-15.1, 0.64-24.5, and 3.47-22.9 µmol L-1 for ammonia, nitrite, nitrate and phosphate, respectively. N/P ratios (2.28-12.8) in the present study indicated that nitrogen is the limiting factor for phytoplankton fluorination except for some sites in the south eastern region. The levels of total polycyclic aromatic hydrocarbons were found affected by the seawater inflows during winter. It can be concluded from obtained data that the south eastern region showed worst water quality parameters.