Widespread heavy metal pollution, coastal erosion and seawater intrusion pose an existential threat to the Nile Delta and put 60 million people in Egypt at risk.
The Nile River is known as the longest river on Earth as it crosses four different climate zones and nine different rainfall systems and extends over 6,650 km from Equatorial Africa to the Mediterranean Sea. In addition, the Nile Delta is an important stopover for migratory birds on their flight route in East Africa.
The effects of pollution are particularly pronounced in Egypt, according to a new study from the University of Southern California’s Viterbi School of Engineering led by Essam Heggy of the Viterbi Innovation Foundation Center for Arid Climate and Water Research, published March 7 in Earth’s Future. , the most populous and driest countries down the Nile, which depend entirely on the river for their sole source of drinking water and crop irrigation.
The country is currently facing one of the largest water budget deficits in Africa after decades of compensating for depleting water supplies through extensive reuse of wastewater, the consequences of which have not yet been studied.
“Roughly the entire population of California and Florida lives in an area the size of New Jersey that is increasingly polluted with toxic heavy metals,” Haji said. must face the reality of this widespread and irreversible environmental degradation.”
In a new study, researchers from the US and Egypt analyzed the grain size and levels of eight heavy metal contamination in sediment samples taken from two branches of the Nile Delta. Key findings included the following:
The sediments at the bottom of the Nile River are highly contaminated with heavy metals such as cadmium, nickel, chromium, copper, lead and zinc.
Pollutants mainly come from untreated agricultural effluents, municipal and industrial wastewater. Without proper treatment of recycled water, concentrations of heavy metals increase and constantly enter the riverbed, unlike organic pollutants, which naturally decompose over time.
Heavy metal concentrations may be exacerbated by increased damming of the Nile River. Huge dams built upstream disrupt the river’s natural flow and sediment flow, thereby negatively affecting its ability to flush pollutants into the Mediterranean, causing toxins to accumulate in sediment over time.
Most heavy metal pollution is irreversible, the researchers said, but the science-based conservation measures proposed in the study could slow environmental degradation and hopefully restore the Nile Delta ecosystem.
Abu Talib Zaki Abu Talib, a research fellow at the Viterbi College of Engineering and co-author of the study, explained: “The worsening water scarcity and the rapid growth of the population in Egypt, which has reached more than 100 million people, have presented local authorities with a dilemma. whether sufficient fresh water should be provided to the sector. “Agriculture is starving to secure food supplies by reusing untreated agricultural drainage water or keeping the Nile river healthy. Balancing is tricky and the results of both options are measurable.”
“Our study confirms the need for more research into the environmental impacts of reusing untreated water and changing river turbidity in light of increased damming of the upper Nile,” Hadji said.
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