Health ecological risk assessment of natural radionuclides and heavy metals in some sediment at Red Sea coast, Egypt

The main objective of this study was to evaluate the health and ecological risks of natural radionuclides and heavy metals based on 23 sediment and water samples collected from some sediment at the Red Sea Coast in Egypt. The studied area is characterised old harbour used for shipping and processing phosphate ore. The results revealed that Cd and Zn contents in some water and sediment samples exceeded the standard limit, their concentrations reached (0.027-0.09) mg/L in water and (4.5-236) mg/Kg in sediment samples respectively. While the other analysed trace elements Fe, Mn, Ni, pb and Cu remain below permissible limits. The estimated contamination degree varied from low to considerable while the ecologic risk indices revealed that sediment ranged 10.8 to 466.6 as from low to moderately contaminate with trace elements. The average activity concentrations of U-238, Th-232, and K-40 were 3.4, 0.83 and 5.5 Bq/L in water and 63.5, 16.5 and 556 Bq/Kg in sediment samples which were below the recommended limits except for the activity concentrations of U-238 and K-40 in some water and sediment samples above the permissible limits. The total annual effective dose rates from the exposure pathway were 0.09 to 0.26 mSv y(-1). The estimated excess lifetime cancer risk values for workers were slightly higher than that of the sediment world average.