Assessment of radiation exposure levels at Alaba e-waste dumpsite in comparison with municipal waste dumpsites in southwest Nigeria

摘要

Radiation exposures at the e-waste dumpsite around Alaba International Market, Lagos and three municipal waste dumpsites located in Ibadan and Ado Ekiti, southwest Nigeria were assessed by gamma ray spectroscopy using a highly shielded Canberra NaI (Tl) detector. Soil samples were collected for analysis at the municipal waste dumpsites for comparison with e-waste dumpsite. Samples were also collected at a location free from waste dumps to serve as control. The mean concentrations of 40 K, 226 Ra, and 232 Th obtained at the e-waste dumpsite were lower than those obtained at the municipal waste dumpsites and the controls site. The values obtained at the e-waste dumpsite were also lower than the world average values of 412?Bq/kg, 35?Bq/kg and 30?Bq/kg for 40 K, 226 Ra, and 232 Th, respectively as reported by UNSCEAR. The mean annual effective dose rate obtained for the soil samples from e-waste dumpsite, Oritaperin, Ring-road and Ilokun dumpsites were respectively 0.026?mSv, 0.074?mSv, 0.080?mSv and 0.093?mSv/yr. The mean absorbed dose rate at the e-waste dumpsite was 21.12nGy/h which is lower than the world average of 60nGy/h. Values for other hazard indices were below the world average and lower than their respective minimum permissible limits. Hence, e-waste and municipal waste does not pose any immediate radiological risk to the people working/living in the vicinity of the dumpsites.