Occurrence of trace elements in coastal seawater of the Egyptian Red Sea

Abstract

The Red Sea serves a main role in the international economy with cargo containers travelling between the Indian Ocean and the Mediterranean Sea, thus shortening the route between Asia and Europe as compared to travelling around Africa via the Atlantic Ocean. In addition to increase development in the regions around it. These aspects impelled us to investigate the pollution degree along the Red Sea coastal areas. Therefore, the present study planned to monitor the trace elements (Pb, Cd, Cu, Zn, Co, Ni, Mn and Fe) in seawater from different regions along the Egyptian Red Sea. Water samples were collected during winter and summer 2019 from nineteen stations representing different environmental situations of the Gulf of Suez, Aqaba Gulf and Red Sea proper. Concentrations of the studied elements were measured using Atomic Absorption Spectrophotometer technique. The investigated elements recorded an annual mean of 1.13, 0.25, 1.24, 11.65, 0.29, 0.97, 0.68 and 14.67 µg/L (in the Gulf of Suez), 1.07, 0.25, 1.27, 11.88, 0.39, 0.88, 1.19 and 12.45 µg/L (in the Aqaba Gulf of) and 0.76, 0.18, 0.95, 12.28, 0.24, 0.63, 0.45 and 15.22 µg/L (in the Red Sea proper) for Pb, Cd, Cu, Zn, Co, Ni, Mn and Fe, respectively. Summer recorded the highest levels of all studied elements except Cd and Mn with significant temporal variations (p < 0.05) for Cu, Zn, Co, Ni and Fe. Gulf of Suez recorded high concentrations of Pb, Cd and Ni, while Cu, Zn, Co, Mn and Fe were presented in the Aqaba Gulf and Red Sea proper, with only significant variations for Ni and Mn (p = 0.004 and 0.025, respectively) between the different studied regions. Finally, levels of the studied elements in seawater from the Egyptian Red Sea were higher than those recorded for the background concentrations in the open ocean, but still lower than the recommended values for water quality.