Seasonal and regional variations of five heavy metals in water, sediments and fishes inhabiting Lake Qarun, Egypt

Abstract

The study was conducted during the period from October 2015 to September 2016 to investigate the accumulation of five heavy metals in three fish species (Tilapia zillii, Solea solea and Mugil cephalus) inhabiting lake Qarun, Egypt. Water, sediments and fish samples were collected from six sites cover eastern, middle and western sectors of the lake during the four studied seasons. The results indicated that, summer time showed the highest pH, salinity, biological oxygen demand and nitrates concentration, while autumn and spring times showed the highest nitrites concentration depending on the site. The abundance of metals in lake water, sediments and fish followed the order: Fe > Zn ≈ Mn > Cu > Cd. In all fish species Fe and Zn exceeded the permissible limits. Regardless fish species, the highest concentrations of metals were recorded in fish liver, while the lowest in fish muscles. Mugilspecies seemed to be more contaminated with metals thanthe other species. It is recommended to coordinate different efforts to rescue Lake Qarun from heavy metal pollution.