Impact of drainage effluents and wind direction on the copper distribution and balance in Abu-Qir Bay, Alexandria, Egypt

Heavy metals entering seawater pose a global threat to marine life and the ecological system. In this regard, this study investigates the mass balance of copper in Abu Qir Bay, a shallow basin located in the western Mediterranean coastal zone of Egypt. The study area is well-thought-out as a fertile marine habitat, which emphasizes the presence of naturogenic and anthropogenic activities. Three land-based sources, namely al-Tabia outfall, al-Maadia outlet, and the Rosetta branch of the Nile River, are seriously affecting the bay causing pollution problems. As part of this research, rainfall, seawater, and drainage water samples were collected to determine and evaluate the relative importance of different sources on the geochemical cycle of copper in the bay. The results revealed that the mean total concentration of copper in the bay was 74.61 ± 18.37 μg/l. Abu Qir Bay receives about 1374.8 ± 171.05 and 643.13 ± 153.03 tons of copper annually from agricultural and industrial discharges, respectively. The outflowing surface water from the bay transports 2463 ton/year of the total amount of copper to the southeastern Mediterranean water. The calculated residence time of copper in Abu Qir Bay was 101 days, while the assimilative factor of copper in the bay amounted to 40 ton.m³/mg.year. As per the findings, a 90 % reduction of the total copper concentration in the bay, in case the external loading stops, can act as an important solution for quick recovery of the bay condition to reach 7.5 μg/l after 121 days.