The Nile is one of the most iconic rivers in the world and, in antiquity, gave birth to a unique civilization that lasted several millennia. However, its delta, once the heart of Lower Egypt, may soon lose all recognizable shape, scientists warn.
“Large-scale heavy metal pollution, coastal erosion and seawater intrusion pose an existential threat to the Nile Delta and endanger 60 million people in Egypt who depend on its resources for all facets of life“say Egyptian and American experts from USC Viterbi. University of Southern California School of Engineering, who published their findings in a new study.
“The impact of pollution is particularly pronounced in Egypt, the most populous and arid country downstream of the Nile, which depends entirely on the river as its only source of water for drinking and irrigating crops. The country currently faces one of the highest water budget deficits in Africa after decades of offsetting water scarcity through large-scale and intensive wastewater reuse, the consequences of which have up to so far been little studied.“, specify the scientists.
The biodiversity of the Nile in danger
The delta’s biodiversity is also under threat, they say, and among the species facing serious threats are migratory birds that use the region as a stopover on their journey along the East African Flyway. .
The researchers came to this conclusion after analyzing contamination levels of eight heavy metals in sediment samples taken from the bottom of two arms of the Nile Delta. They found that the samples were heavily contaminated with toxic heavy metals, including cadmium, nickel. , chromium, copper, lead and zinc.
These pollutants, they say, come mainly from untreated agricultural wastewater, municipal waste and industrial wastewater. “Without proper treatment of reclaimed water, heavy metal concentrations increase and become permanently embedded in the river bed unlike organic contaminants which naturally degrade over time.“, they explain in a statement about their findings.
“Heavy metal concentrations could be exacerbated by increased damming on the Nile. The mega-dams built upstream disrupt the natural flow of the river and the flow of sediments and therefore negatively affect its ability to expel pollutants into the Mediterranean Sea, allowing toxins to accumulate in bottom sediments over time. time.“, They continue.
Heavy metal contamination is irreversible
Alarmingly, much of this heavy metal contamination is irreversible. However, science-based conservation measures could mitigate environmental degradation and restore the Nile Delta ecosystem to relatively healthy levels.
“Worsening water stress and Egypt’s rapid population growth of over 100 million has placed local authorities in the dilemma of providing enough fresh water to the parched agricultural sector to ensure food supply. through water reuse agricultural drainage without treating or preserving the health of the Nile River,” says Abotalib Z. Abotalib, postdoctoral researcher at USC Viterbi and co-author of the study. “The balance is difficult and the consequences of both options are measurable”.
Unless decisive action is taken, the implications of heavy metal pollution will be disastrous for everyone who depends on the delta’s water and biodiversity, points out Essam Heggy, an Egyptian rocket scientist who was a another of the study authors. .
“You have roughly the combined populations of California and Florida living in an area the size of the state of New Jersey that is increasingly contaminated with toxic heavy metals. Today, the civilization that has thrived in a scenic waterscape for more than 7,000 years must face the reality of this large-scale irreversible environmental degradation.said Heggy.
More Nile Water Recycling Research
“Our study underscores the need for more research on the environmental impacts of recycling raw water and changing river turbidity due to increased damming upstream of the Nile.” new sampling campaigns in this area could inform future conversations and collaborations among Nile Basin nations, who have a common interest in maintaining a healthy Nile system.“.