Assessment of heavy metals concentrations in water, plankton and fish of Lake Manzala, Egypt

Abstract

he levels of some heavy metals (Cu, Zn, Cd, Pb) were determined in water, plankton and fish (Liza aurata) collected from five sites in Lake Manzala. Metals in water and fish exhibited a significant seasonal and regional variations in which all metals attained their maximum values during summer, while the lowest level was reported during winter. The accumulation of different metals in water, plankton and fish tissues followed the order Zn> Cu> Pb> Cd. The mean concentrations of the tested metals in water were: Cu (0.055), Zn (0.311), Cd (0.020) and Pb (0.022) mg/l. Cd level in water was found to be higher than the permissible limit recommended for drinking water. Metals in plankton were much higher than those in water and fish. Gills of the examined fish contained the highest concentrations of all the measured metals, while muscles retained the lowest levels. In spite of the contamination of Lake Manzala by such heavy metals, the levels of these metals in the edible fish muscle did not exceed the recommended permissible limits and thus are considered safe for human consumption.

Valuation of water pollution using enzymatic biomarkers in aquatic insects as bioindicators from El-Mansouriya stream, Dakahlia, Egypt

“…Meanwhile, metal pollution index (MPI) provides a representative picture of the environmental state of any environmental impacts on the aquatic ecosystem (Mokhtar et al, 2009). Hence, in current results the increments in MPI values in selected stream were attained in hotter seasons (spring, summer) and its decrements were observable during cooler seasons (autumn, winter), that might be related to the increased metabolism of aquatic invertebrates (Khaled, 2004;Bahnasawy & Khidr, 2011).…”

“…Similarly, Tayel et al (2008) observed that increase of heavy metals accumulation in fish, returned to the increase of total dissolved metals in Nile water and sediments. Also, Farombi et al (2007) and Bahnasawy & Khidr (2011) found that the presence of higher concentration of metals in different fish species, due to exposure to higher concentration levels of these elements through water and sediments. Meanwhile, metal pollution index (MPI) provides a representative picture of the environmental state of any environmental impacts on the aquatic ecosystem (Mokhtar et al, 2009).…”

Prevalence and Intensity of Helminth Parasites of African Catfish <i>Clarias gariepinus</i> in Lake Manzala, Egypt

“…Lake Manzala is the largest lake in the northern region of Egypt and the most productive for fisheries [14]. It extends between longitudes 31˚45' -32˚22'E and latitudes 31˚00' -31˚30'N.…”

Preliminary assessment of heavy metals in water, sediment and macrophyte (Lemna minor) collected from Anchar Lake, Kashmir, India

“…Due to anthropogenic activities, the level of these metals in the environment has increased tremendously during the past decades. The increase in heavy metals in this lake water and sediment might be due to the fact that this region receives huge quantities of sewage, agricultural run-off and toxic effluents from the SKIMS institute (Salim et al 2013), whereas seasonal variation in metal concentrations at different sites may be attributed to the fluctuations in the amount of agricultural run-off and sewage effluents discharged into the lake (Bahnasawy et al 2011 andKhan et al 2012).…”

“…The fact that there was a significant difference in Ni concentrations among different sites suggests the presence of an anthropogenic input of Ni. The increase in heavy metals and metal ions might be due to the fact that this lake receives large quantities of sewage, agricultural run-off and effluents from the agricultural fields, settlement effluents, whereas seasonal variation in metal concentration at different sites may be attributed to the fluctuations in the amount of agricultural run-off and sewage effluents discharged into the lake (Bahnasawy et al 2011;Khan et al 2012). Generally the highest concentrations of heavy metals in water and sediment were observed during autumn season, and this could be due to death and decay of the macrophytes that release their locked up elements in the growing media.…”