Risk Evaluation of Heavy Metals in Sediments of the Fish Farming Area in the Mediterranean Section of Lake Manzala

Abstract

To reveal the potential pollution characteristics of heavy metals in sediment of the fish farming area in the Mediterranean section of Lake Manzala, three indices of Enrichment factor (EF), Nemerow multi-factor, and Hakanson potential ecological risk factor have been used. The reference values for calculating these indices were the background levels in the same area. The averages of EF values are in the following order: Cu>Zn>Cd>Pb. The average of pollution indices (PI) and Contamination Factor (C i f) descended in the order of Fe > Cu > Zn > Pb > Cd. The NIPI values in sediments ranged from 0.36 to 15.57 indicating lightly polluted to severe or high level of pollution with an average of 6.68 (severe or high level of sediment pollution). The average contamination value (Cd) was 28.12, reflecting relatively high contamination degree. In terms of the mean potential ecological risk indices of the four types of heavy metals, the Eif arrayed is in the order of Cu > (Cd > Pb) > Zn. Cu was the key influence factor to cause the potential ecological risk, and its Eif mean value was up to 37.63 with risk grade (medium). The scope of RI range was 36.25 and 92.96 with ecological risk levels slight and strong respectively.