According to new research from the USC Viterbi School of Engineering, extensive heavy metal pollution, coastal erosion, and seawater intrusion pose an existential threat to the Nile River Delta and endanger 60 million people (roughly twice the population of Texas) who depend on its resources for every aspect of life in Egypt.
Also, throughout their route along the East African flyway, migratory birds must stop at the Nile River Delta.
On Tuesday, March 7, the journal Earth’s Future published the study, which was conducted by Essam Heggy of the USC Viterbi Innovation Fund Arid Climates and Water Research Center.
Egypt, the most populous and desert country downstream of the Nile, is particularly affected by the pollution because it depends totally on the river for its water supply for drinking and crop irrigation.
After decades of making up for declining water supplies with intense, large-scale wastewater reuse, the effects of which have been under study until now, the nation today has one of the biggest water budget deficits in Africa.
“You have roughly the combined populations of California and Florida living in a space the size of the state of New Jersey that is increasingly polluted by toxic heavy metals,” said Heggy. “Today, the civilization that thrived in a scenic waterscape for over 7,000 years must face the reality of this irreversible large-scale environmental degradation.”
Eight heavy metals were examined for the study’s grain size and pollution levels in samples of bottom sediment taken from two branches of the Nile River Delta by researchers from the United States and Egypt.
Major conclusions included:Heavy metal contamination in the sediment near the Nile River’s bottom includes cadmium, nickel, chromium, copper, lead, and zinc.
Much of the heavy metal contamination is irreversible, the researchers said
Untreated agricultural drainage, as well as urban and industrial wastewater, are the main sources of contaminants.
Heavy metal concentrations rise when recycled water is not properly treated and remain in the riverbed permanently, unlike organic pollutants that break down over time.
Increasing the Nile’s damming could make heavy metal concentrations worse. Mega-dams constructed upstream interfere with the river’s natural flow and sediment flux, which negatively affects its capacity to discharge contaminants into the Mediterranean Sea and causes poisons to accumulate over time in the bottom sediment.
“The aggravating water stress and the rapid population growth in Egypt, reaching above 100 million, have put local authorities in a dilemma whether to provide sufficient fresh water for the thirsty agricultural sector to secure the food supply through reusing untreated agricultural drainage water or to preserve the health of the Nile River,” said Abotalib Z. Abotalib, a postdoctoral researcher at USC Viterbi and co-author of the study. “The balance is challenging, and the consequences of both choices are measurable.”
“Our study underscores the need for more research on the environmental impacts of untreated water recycling and the change in river turbidity under increased upstream damming of the Nile,” Heggy said.
Continued research with more sampling campaigns in the nile river delta area could inform future conversations and collaborations among nations of the Nile River Basin, who have a shared interest toward maintaining a healthy Nile River system.
Source:USC University Of Southern California
