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. Mugil species seemed to be more contaminated with metals than the other species. It is recommended to coordinate different efforts to rescue Lake Qarun from heavy metal pollution.

Metal Pollution, Environmental Assessment and Suggested Solutions in the Recent Bottom Sediments of Qaroun Lake, Fayoum, Egypt

“…On the other hand, the central area had more zinc (Zn), cobalt (Co), rubidium (Rb), and strontium (Sr), which matches what El-Kady and others found in 2019, where they also saw that metals were more concentrated in the eastern part of the lake, especially near El-Batts drain (El-Kady et al, 2019). In all three parts of Qaroun Lake -east, middle, and west -there was a lot of iron (Fe), even more than recorded (Elwasify, 2019); it shows that the sediment has more iron than usual, which probably comes from the land around the lake and is causing pollution (Bantan et al, 2020; Ejaz et al, 2020). When we looked at the results from this study and compared them to earlier ones about Qaroun Lake, we saw that there was more manganese (Mn), copper (Cu), and zinc (Zn) than what those previous studies found by (Elwasify, 2019) Regarding the content of organic matter in the current study, it was like those obtained by El-Zeiny et al…”