Evaluation of the ecological health and food chain on the shores of four River Nile Islands, Egypt.

This study was conducted to evaluate the impact of human activities on the ecological health and food chain at the shores of four Nile Islands in Great Cairo including El-Qeratten, El-Waraq, El-Zamalek, and El-Manial. Water quality, bacteria, phytoplankton, benthic algae, zooplankton, macrobenthic invertebrates, and bony fishes were examined at each island shore over two seasons including the lowest and the highest flow (February and July 2020, respectively). The obtained results showed that the average values of most of the chemicals in Nile Island's water were within the Egyptian water quality limits. Discriminant analysis of physicochemical factors revealed a similarity between El-Waraq and El-Qerateen and between El-Manial and El-Zamalek. El-Qeratten was the most polluted island. It has the highest total and fecal coliform bacteria count (3.155 and 3.050 Log MPN/100 mL, respectively). El-Zamalek shores have the highest phytoplankton (33,582 cells × 104 L-1) and zooplankton count (310,891 organisms × m-3) and phyto-biochemical values. Biochemical analysis of phytoplankton demonstrated the richness of the bulk by protein (> 85% of biomass), indicating that phytoplankton has a high nutritional value. Elevated zooplankton count was recorded at El-Zamalek, which coincided with the peak of phytoplankton abundance. Mollusca were the dominant macrobenthic invertebrates on most of the island's shores. Bony fishes were represented by 27 species and two crustaceans. The levels of the metals in fish samples were compared with the food safety guideline endorsed by the World Health Organization and Food and Agriculture Organization (WHO/FAO) to evaluate the toxicity level.

Ecological risk assessment of heavy metal pollution in sediments of Nile River, Egypt.

The Nile River is the soul of Egypt, providing more than 95% of its freshwater demand. However, it receives different pollutants discharged into the water body along its stretch from Aswan (downstream of the High Dam) to Cairo, which is approximately 950 km. Alternatively, sediments play an important role in the dynamics of the entire aquatic environment and act as a sink or a source of pollution in the overlying water under various conditions. This study assessed sediment quality and its heavy metal levels. Several indices and human health risks were determined to assess the potential ecological risk of the Nile River sediment. On the basis of the index results, Cd registered the highest pollution ranking, whereas Fe, Mn, Zn, Cu, and Ni had the lowest effect. In another context, southern sites represented the lowest ecological risk relative to the central and northern sectors. The results of the noncarcinogenic hazard indices, hazard quotient, and hazard index in addition to the lifetime cancer risk were below the acceptable international limits, confirming that there are no adverse effects on the exposed population due to the Nile sediment.