Health Risk Assessment of Natural Radioactivity in Wasteland Soils in Okakarara, Namibia

Human activities such as waste disposal tend to impact negatively on the environment. Some waste products are associated with elevated levels of natural radioactivity. It was therefore, the aim of the study to investigate the health risk associated with natural radioactivity from Okakarara municipal waste dumpsite. In this study, gamma spectrometric analysis was used to determine the activity concentrations of Ra-226, Th-232 and K-40 in 18 soil samples. From these activity concentrations, some radiological parameters were calculated. The average activity concentrations of Ra-226, Th-232 and K-40 in (Bq.kg(-1)) were 15.45 +/- 0.47, 18.00 +/- 0.55, and 215.73 +/- 4.29, respectively. The average Ra-eq value was 57.80 +/- 0.98 Bq.kg(-1). In all the samples, Ra-eq values were found to be lower than the worldwide value of 370 Bq.kg(-1). The absorbed dose rate was found to be 27.00 +/- 0.44 nGy.h(-1), whereas an average value of 0.03 mSv.y(-1) for AEDE was noted, which is less than 0.48 mSv, the worldwide average. The Annual Gonadal Dose Equivalent (AGDE) was 190.89 mu Sv.y(-1), a value less than the world average of 298 mu Sv.y(-1). The average values of the Representative Level Index (RLD and the External Hazard Index (Hex) was found to be 0.43 and 0.16., respectively. These indices were less than unity. The average value of the excess lifetime cancer risk (ECLR) was 1.16 x 10(-4??units). This value was lower than the internationally acceptable limit of 2.9 x 10(-4??). From these results it can be concluded that natural radioactivity from the wasteland area of Okakarara was not an issue of health concern.

Automated summary

The study aimed to assess the health risks associated with natural radioactivity from Okakarara municipal waste dumpsite, revealing that the levels were within acceptable limits internationally, indicating no significant health concerns from the natural radioactivity at the site.