Background radiation levels in selected dumpsites in Nnewi community setting Southeast Nigeria

Nnewi town has undergone a marked increase in industrialization over the years. Considering the continuous disposal of automotive and hospital wastes in dumpsites within the town there is a need to ascertain the background radiation level of some of its dumpsites.

 To evaluate the level of background radiation in some selected dumpsites in Nnewi and compare the background radiation dose levels with the worldwide recommended average natural dose of 2.4mSv/yr to humans.

The levels of background radiation in these dumpsites were estimated using a well-calibrated International Medicom CRM-100 Digital Radiation Monitor (survey meter). A cross-sectional survey was adopted for this study. Following the standard procedure, the radiation monitor was held at a distance of 1.0 meters above the ground and three readings are taken at each location and the mean recorded. The Annual Absorbed Dose Rate (ADR), Absorbed Dose Rate (AD) and the Annual Equivalent Dose Rate (AEDR) were calculated. Descriptive statistics were used to summarize the data using Statistical Package for Social Sciences SPSS version 20.

 The mean of the calculated Annual Absorbed Dose Rates recorded at 21 and 24 meters was marginally greater than the accepted exposure rate for the public with the values of 1.5 mSv/year respectively. At 12 and 27 meters, the values were 1.5 mSv/year for Bank Road dumpsite respectively. Other distances were below the limit of 1mSv/year for the public and also below the dose limit of 20mSv/year for radiation workers as recommended by the ICRP.

 The radiation levels emitted from the study area were within permissible limits for the general population. Therefore there is little risk of instantaneous radiation hazard with an estimated safety zone at 6 meters from the dumpsites.