Irreversible and Large‐Scale Heavy Metal Pollution Arising From Increased Damming and Untreated Water Reuse in the Nile Delta

Abstract

Egypt observes one of the highest water budget deficits in Africa that is mainly compensated by intensive reuse of untreated agricultural drainage water in the Nile Delta. The implications of untreated water reuse on increasing soil pollution levels remain poorly characterized; however, a large‐scale pollution can compromise crop production and water quality. To address this deficiency, we evaluate the level of heavy metal pollution in the Nile Delta, identify its sources and explore the implications of damming on heavy metal concentration using integrated pollution indicators and statistical modeling. Pollution indicators show moderate to very high contamination by Pb, Ni, Cr, Cd, Cu, and Zn, with unprecedented Cd levels in the sediments (up to 72.0 ppm) and a northward increase in pollution levels. Statistical modeling and historical datasets reveal the association of Cd and Fe on both Nile branches and the clustering of Pb, Ni, Cu, Zn and Cr, which attribute the heavy metal concentrations to the cumulative addition of untreated agricultural drainage water (9.5 BCM/yr) and wastewater. These processes introduced an accelerated pollution in the Nile Delta system. Though, conservation measures are crucial to reverse this degradation, yet the increasingly engineered Nile flow, the low gradient of the delta and the active silting impede heavy metal flushing causing irreversible pollution. Our findings alarm future increase in heavy metal pollution in response to increased untreated drainage water reuse to mitigate the impacts of ongoing upstream damming and call for implementing international cooperative agreements for integrated water management along the Nile River.

Resolving Mega-Dams Energy-Water Nexus in the Eastern Nile Basin During Prolonged Droughts

“…It is important to note that the ndings reported in our hydraulic simulation could have some quanti able margins that do not alter the trends observed in our results. These include the uncertainties associated with using the historical versus stochastic ow models, the Nile riparian's current and projected socioeconomic states, and environmental concerns on water quality that are partially covered in a separate study 50 . The Nile River has a long record of more than 102 years of hydraulic ow measurements.…”

Ground-Based Hyperspectral Retrieval of Soil Arsenic Concentration in Pingtan Island, China

“…The geochemical data obtained from investigating soil heavy metals have proven to be precise, making it a reliable basis for ecological risk assessments in various studies [54][55][56][57][58]. However, these data are generally discrete, sparse and relevantly stationary, which cannot satisfy the frequent and rapid monitoring requirement for a wide area.…”

Morphological Variation between Life and Death Gastropod Populations in the Nile Delta: A Pollution-Induced Evolution

“…Strongly right-skewed histograms generally indicate higher rates of juvenile mortality [96]. Manzlala Lake is classified as mesotrophic to eutrophic, with higher organic matter and nutrient enrichment due to agricultural discharge into the lagoon [97,98], which indicates that competition for nutrients is not a main factor. Therefore, we have attributed the decrease in size and morphologic breadth in the life population to the pollution by heavy metals.…”