Egyptian scientist Essam Hajji for Al Jazeera Net: Heavy elements in the Nile River Delta are an imminent health and environmental threat

The impact of pollution is particularly evident in Egypt, the most populous and driest country downstream of the Nile, which relies entirely on the river as its sole source of drinking water and crop irrigation.

The country is currently facing one of the highest water budget deficits in Africa – since 2000 – after decades of attempts to compensate for dwindling water through wastewater reuse, the consequences of which have yet to be studied.

A new study, led by Egyptian scientist Essam Heggy, sheds light on the effects of untreated wastewater reuse and the extent of pollution resulting from it, as well as identifying the environmental impacts of new dams on the riverbed.

The team analyzed the pollution levels of 8 heavy elements in 20 samples from the bottom of the Nile Delta Damietta and Rasheed branches, and the paper was published in Earth's Future on March 7.

According to a press release published on Phys.org (Phys.org) on March 9, the study, which was the result of an Egyptian-American collaboration involving researchers from Viterbay California College, Minia University, and the National Institute of Oceanography and Fisheries in Cairo, highlights the seriousness of this large-scale pollution, coastal erosion and seawater intrusion that challenges the sustainability of the Nile Delta as a primary source of Egypt's food security and its implications for the health of more than 50% of Egypt's population.

In an interview with Al Jazeera Net via social media, the leader of the study, Dr. Essam Hajji, a researcher at the USC Viterbi School of Engineering, spoke about the motivation behind initiating this research effort, its results and proposed solutions to avoid the risks of worsening pollution on the ecological balance in the Nile River Delta and its impact on the health of 60 million Egyptians.

The study was led by Dr. Essam Heggy, a researcher at USC Vitterbay School at the University of Southern California (Essam Heggy's Facebook page)

• What is the first motivation for determining the area under study?

The Nile Delta represents a very important area for the Egyptian economy and the ecosystem in the southern Mediterranean, and the delta has been subjected to many environmental changes as a result of various human activities and the rapid expansion of urban areas at the expense of agricultural land areas and waterways, and therefore it was necessary to conduct a regional analysis of the response of the benthic sediments of the Nile River in the delta to these developments.

Despite the importance of assessing the soil quality of the Nile River branches in the Delta, previous studies have remained far from broadly assessing heavy element concentrations without using an advanced research methodology to understand the sources of pollution, the relationship of pollutants to each other, and the effects of different surface processes in the Delta on soil quality.

For most stations in the Rashid branch, elemental concentrations show a gradual increase northward with increasing distance from the point of division of the Nile River at the Delta Barrage. On the other hand, an increase to the north was observed in the Damietta branch of the elements zinc, manganese and copper only, while concentrations of nickel, iron, cadmium, chromium and lead show a random distribution without a clear direction.

Physical and geochemical analyses also indicate increasing levels of pollution in silt accumulated at the bottom of the Nile, confirming the presence of heavy elements such as cadmium, nickel, chromium, copper, lead and zinc.

According to the study, the spread of these pollutants is mainly due to the reuse of agricultural wastewater and municipal and industrial wastewater without treatment, in addition to the fact that the continued construction of high dams will inevitably aggravate this pollution and thus cause a real threat to the health of citizens.

The results of the study highlight the impact of not properly treating recycled water on the ecosystem from an increase in the concentration of these elements and their integration into the silt accumulated on the river bed, which inevitably exacerbates this pollution over time unlike organic pollutants that decompose naturally.

Essam Heggy says pollution from increased concentrations of heavy elements is exacerbated by the construction of dams such as the Renaissance Dam (French)

• On the mention of the effects of dams in the study, what are the expected environmental risks and conflicting opinions about these risks?

This pollution caused by increased concentrations of heavy elements is expected to be exacerbated by the construction of dams such as the Renaissance Dam on the course of the Nile, where large dams built upstream affect the flow of sediment and disrupt its natural flow rate, hindering its ability to automatically expel pollutants into the Mediterranean Sea to eventually accumulate at the bottom permanently.

The danger of this pollution is that it is irreversible, that is, there is no way to get rid of it, but the science-based conservation measures proposed by the study could slow the deterioration in the hope of restoring the balanced ecosystem of the Nile Delta.

The process of building mega dams of this type has long been banned in America and Europe due to their known environmental impacts, but the lack of laws and regulations that regulate or prevent the construction of dams has made building and investing in them an easy solution to be resorted to without paying attention to its environmental consequences or its impact on water and soil quality.

This is where science comes into play in proving or denying potential harms in a systematic and institutionalized manner, especially for easy access to data and sample collection for Egyptian researchers and then assessing the damage to us ourselves.

This has also been one of the motivations behind this and other research efforts being worked on so far with a group of diligent Egyptian researchers.

Representative samples were taken for the areas under study from the different sectors of the Nile River branches in the Delta (NASA)

• Given the ease of access to data and sample collection, is the number of samples taken in the study tellingual to conclude that there is a real threat to 60 million Egyptians?

The samples were collected according to a studied scientific methodology to ensure that they are representative samples of the areas under study from the different sectors of the Nile River branches in the Delta, in order to form a general and spatial idea of the level of pollution in the Delta. The small number of samples has been compensated by their integration with previous studies, statistical analyses and data of various water uses in the delta.

However, there is no doubt that the use of a larger number of samples (at least 100 samples) should be done periodically to obtain a more accurate picture of pollution levels, as pollution levels are expected to vary between periods, so the more samples, the higher the quality of the research output.

• According to published research, the total concentration of heavy elements was measured using XRF, and have other images of these elements, such as dissolved and biological images, been taken into account because of their direct effects on the ecosystem and human beneficiaries?

The study focused on the levels of pollution from heavy elements that cannot be easily eliminated under the geomorphological and hydrological situation (soil and water situation) of the Nile River Delta, and due to the nature of the treatment of agricultural and sanitary drainage water that cannot purify water from heavy elements unlike other pollutants.

• Have any of the approved environmental quality indicators or any previous studies analyzed pollution levels been consulted to compare them with those measured during your research?

Several previous studies, whether small-scale or regional, have been compared, and these comparisons have concluded that the level of pollution in the delta increases steadily over time as a result of the increased reliance on triple untreated agricultural and sanitary drainage water for irrigation.

Due to the high cost of wastewater treatment before use, coordination must be made with all Nile Basin countries (Shutterstock)

• In light of the study, what are the short- and long-term implications of such worsening pollution?

One of the direct short-term effects of the pollution of the Nile River bed soil is the lack of productivity of agricultural crops, especially rice, as a result of the increase of some heavy elements such as cadmium in water and soil; in the long term, the continued accumulation of heavy elements in the soil of the Nile River may lead to toxic levels of these elements, especially cadmium and lead, which may lead to the deterioration of the aquatic environment and plant health and population in the delta region.

• What scenarios do you think are proposed to avoid or mitigate the expected increase in pollution as a result of untreated wastewater and dam impacts?

Due to the high cost of treating wastewater before its use, coordination must be made with all Nile Basin countries to reach a joint cooperative management of dams and Nile River flows, so that dependence on untreated wastewater in the Nile Delta can be reduced in a way that does not affect water shares or electricity production in the Upper Nile countries. The competent authorities should also expand the regulation of rules for the substitution of water-hungry crops and the selection of less water-intensive crops in the Nile Delta.

It is important that the State also intensify its efforts to raise widespread awareness of the need to preserve the Nile waters and canals through government awareness campaigns.

In conclusion, I emphasize that the aim of the study is not to cause panic when it was originally to sound the alarm about the need to treat wastewater before reusing it, in addition to paying attention to the dangers of dams being built on the course of the Nile River.

I recommend moving quickly to study this problem closely and work to find effective solutions to mitigate the growing risk of pollution caused by the construction of dams upstream of the Nile.