Environmental assessment of radionuclides levels and some heavy metals pollution along Gulf of Suez, Egypt

Abstract

This work aims to evaluate radioactivity levels of 238U (²²⁶Ra), ²³²Th(²²⁸Ra), and ⁴⁰K and the associated radiological hazard indices, as well as to assess the current status and concentrations of heavy metals along the coastline of the Gulf of Suez, in order to identify potential sources of contamination and to construct radioactivity baseline for this area. Measurements of the activity concentrations of ²³⁸U(²²⁶Ra), ²³²Th(²²⁸Ra), and ⁴⁰K in Bq kg^-1 of the collected samples were carried out using high-purity germanium (HPGe) detector. Heavy metals in seawater, shore sediment, and algae samples were determined using ICP-OES. The average activity concentrations of ²³⁸U(²²⁶Ra), ²³²Th(²²⁸Ra), and ⁴⁰K were found to be 13.79 ± 0.75, 14.57 ± 1.15, and 128.9 ± 4.15 Bq kg^-1, respectively. The radiological hazard indices of absorbed dose rate in nGy h^-1 (D), annual effective dose rate in mSv y^-1, AED, radium equivalent activity in Bq (Ra_eq), external and internal hazard indices (H_ex, H_in), and cancer risk factor were calculated and compared with the worldwide averages. The distribution patterns of annual effective dose (AED) at the Suez Gulf showed that the south east of the Gulf is characterized by higher AED. Water quality parameters (water temperature, salinity, pH, DO, and Eh) reveal that Suez Gulf was undoubtedly affected by the rate of the human activities. Heavy metal concentrations in shore sediments showed some variation within the study area and followed the following order: Fe > Mn > Zn > Al > B > Co > Ni > Pb > V > Cr > Mo > Cu > Cd. Furthermore, heavy metal concentrations indicated that northern part of the Gulf contains the highest levels of these metals compared to the southern one.

Keywords: Environmental samples; Heavy metals; Radiological hazard indices; Radionuclides; Suez Gulf.