Levels of Cs-137, natural radionuclides and heavy metals in soil of Al-Negila area, Northwestern Coast of Egypt: distribution and risk assessment

Radionuclides and heavy metals/metalloids content in soils shore sediments of Al-Negila area (Matrouh, Egypt) were determined to assess the associated environmental risks. A total 46 soil sediment samples collected analysed for natural man-made radionuclides (238U series, 232Th 40K 137Cs) (Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mn, Ni, Si, Sr, Zn, Hg). Within study area, are mainly calcareous with sandy, sandy clay silty sized textures. The concentrations higher than those sediments, meanwhile, they within safe world average values. estimated (±SD) activity 226Ra, 228Ra, 137Cs 20.3 ± 5.3, 17.8 6.3, 353.1 129.8, 2.7 Bq/kg, respectively. concentration is characterised by greatest variability characterising fallout deposited radionuclides. values Raeq (72.9 23.7 Bq/kg), air absorbed gamma dose rate (34.9 11.4 nGy/h), annual effective (42.8 14.0 µSv/y), external hazard index (0.2 0.1) lower international averages reported UNSCEAR 2008. (mg/kg) decrease following order: Mn (129.8) > Sr (95.0) Si (28.8) Ba (25.7) Zn (25.1) Cr (17.6) B (10.0) Ni (3.9) Cu (3.3) Co (0.5) Cd (0.007) Hg (7.0 µg/kg). According classes pollution load contamination degree indices, generally uncontaminated. However, a few sampling sites considered moderately contaminated Sr. metal/metalloid contents should be observed assessed regularly, especially 137Cs.