Health Risk Assessment of Natural Radioactivity in Wasteland Soils in Helao Nafidi dumpsite, Namibia

Abstract

Humans are exposed to radiation in the soil of wasteland areas because radiation occurs naturally in the environment through cosmic and terrestrial rays. Children and residents from the neighborhood use dumpsites every day to scrounge for food and other items, increasing their exposure to radiation. The aim of the study is to ascertain whether the radioactive compounds found in the Helao Nafidi dumpsite pose a threat to human health. In this work, the activity concentrations of 226Ra, 232Th, and 40K in 19 soil samples were measured using a gamma-ray spectrometer. Several radiological parameters were computed from these actions. The average activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K were 4.83 ±0.58, 4.72 ±0.62 and 51.31±5.41, respectively. The average Ra_eq value from the Wasteland soil was 15.53 Bq/kg. All of the soil samples had Raeq values that were less than the average global value of 370 Bq/kg. The average AEDE value was 0.01 mSv.y-1, less than the 0.48 mSv global recommendation. The Wasteland soil's Annual Gonadal Dose Equivalent (AGDE) value was 50.77 Sv.y-1, which was found to be less than the 298 Sv.y-1 global critical value.  The average values of RLI and Hex were found to be 0.11 and 0.04, respectively. These indices were less than the world accepted-limit values. The average value of the excess lifetime cancer risk (ECLR) was found to be 0.03  and lower than world average of 2.9 x . These findings indicate that natural radioactivity in the soil of the Helao Nafidi wasteland area is not now a health risk.