Seasonal Variation of Water Physicochemical Parameters and Trace Metals in Lake Manzala, Egypt

Abstract

Manzala lake is the largest costal lake east Nile Delta and is considered as one of the most dynamic ecosystems along the Egyptian coast on the Mediterranean Sea. It is ecologically and economically important due to biological diversity, valuable fish, and wild life resources. The lake has undergone a considerable reduction in surface area due to input from human activities. This costal Lake constitutes an estuarine environment with a very particular behavior. The purpose of this investigation is to measure the general hydrological parameters (salinity, temperature, pH, dissolved oxygen, nitrate, nitrite, ammonia, phosphate) and concentration of trace metals (Fe, Zn, Cu, Mn, Cd, Pb) at seven stations in the Lake during four seasons (Jan.-Oct. 2012). The salinity ranged between(0.55-36) depending on seasonal bases. The pH, dissolved oxygen, nitrate, nitrite, ammonia, and phosphate had weak relation with salinity. The temperature of the lake varied according to the seasons. The pH of water ranged between (5.2-8.8). Dissolved oxygen (DO) of the water decreased with temperature, and increased with photosynthetic activity of the producers. There was strong correlation found between both Fe and Mn concentrations with salinity while the concentration of Cd, Cu, and Zn showed negative correlation and salinity.The concentrations of the measured trace metal were found in the following order Fe > Mn > Cu > Zn > Pb > Cd. Metal concentrations in the water indicate an increase in the pollution load due to movement of fertilizers, agricultural water, prawn cultivation and Motor Boat operations. An immediate action from the stakeholders is required in order to protect the lake from further pollution.

Effects of seasonal variations and pond age on trace elements and their correlations with plankton productivity in commercial freshwater crayfish ( cherax cainii austin, 2002) earthen ponds

“…Research suggests that an increase in silicate concentration corresponds approximately with that in phosphate concentration (Heron, ). Contrary to our findings, El‐Saharty () found a reduction in phosphate concentration during the autumn, due to an increase in uptake of phosphate by phytoplankton. P was decreased due to the presence of phytoplankton in a study by Sierp and Qin ().…”

“…The seasonal fluctuations of trace elements can largely be credited to environmental factors, including temperature, evaporation and rainfall and plankton dynamics (Adhikari & Ayyappan, 2004;Dickson, 1975;Gibson, Wang, & Foy, 2000;Hecky, Kling, & Brunskill, 1986;Kimball, 1973;Sierp & Qin, 2001; Zhang et al, 2013). Farming practices, such as liming, water sources, feeding, fertilization, harvesting, cleaning the pond bottom soil at harvest and overnight drying, may also have an effect (Abu Hena et al, 2018;Adhikari, 2003;Borg, Ek, & Holm, 2001;Boyd, 1997;Christos, Miltiadis, & Theodore, 2018;El-Saharty, 2014;Shaked, Erel, & Sukenik, 2004). Furthermore, the fluctuations in plankton abundance and phytoplankton species diversity (Table 2) can relate to changes in the concentrations of trace elements, sunlight hours and temperature (Calijuri, Santos, & Jati, 2002;Sommer et al, 2012).…”

“…Cu concentration during the autumn may be high enough to be toxic for some plants (Riley, ). High levels of free Cu and low levels of Fe are harmful for phytoplankton (Sunda, Barber, & Huntsman, ) and can reduce growth and reproduction in plants (El‐Saharty, ).…”

Assessment of Water Quality and Bacteriological Indicators of Sewage Pollution in Bahr El-Baqar Drain, Eastern Nile Delta, Egypt

“…The comparison of water quality physico-chemical parameters and major dissolved ions in this study and those of previous studies in Bahr El-Baqar drain, Lake Manzala and the River Nile are reported in Table 3. It is concluded that the average value of pH (7.48) in this study is higher than (6.6-7.35) previously reported in the water of Bahr El-Bagar and Kitchener drains [12,18,20], while it is lower than those of [1,5,7,11,16,25,[27][28][29][30][31]33] (Table 3). The average TDS (1685.8 mg/L) in the drain water is higher than (2.8-1485 mg/L) repored before [5,12,[29][30]33], however, it is below those of [1,16,[27][28] (Table 3).…”

“…It is concluded that the average value of pH (7.48) in this study is higher than (6.6-7.35) previously reported in the water of Bahr El-Bagar and Kitchener drains [12,18,20], while it is lower than those of [1,5,7,11,16,25,[27][28][29][30][31]33] (Table 3). The average TDS (1685.8 mg/L) in the drain water is higher than (2.8-1485 mg/L) repored before [5,12,[29][30]33], however, it is below those of [1,16,[27][28] (Table 3). The average EC (2864 μS/cm) in the drain water is much higher than (276-2500 μS/cm) in most previous studies [1,5,12,18,20,29,[32][33], while it is lower than those of [11,16,31].…”