Determination of radon in soil and water in parts of Accra, and generation of preliminary radon map for Ghana

The research was focused on determining the radon levels in soil and water in parts of Accra, generate a preliminary radon map for Ghana and estimate a pilot reference level for the country, using the data obtained from this research and collated data from other researchers. The radon gas measurement was done with the passive method, using the SSNTDs which are sensitive to alpha particles emitted by radon. Cellulose nitrate LR – 115 type II alpha particle detectors were used. The detectors were chemically etched in a 2.5 M NaOH solution at a temperature of 60 °C for 90 minutes, after two weeks and two months of exposure to soil and water respectively. The images of the etched detectors were acquired by means of a scanner and then tracks counted with ImageJ software. Inverse Distance Weighing (IDW) method of ArcGIS 10.2 was used to spatially distribute the radon concentration on a map. The average soil radon concentration in the study area ranges from 0.191 kBqm^-3 to 3.416 kBqm^-3 with a mean of 1.193 kBqm^-3. The radon concentration in water from the study area ranges from 0.00346 BqL^-1 to 0.00538 BqL^-1 with an average of 0.00456 BqL^-1. A strong negative correlation has been established between radon in soil and water in the study area. The preliminary national average indoor, water and soil radon concentrations are 137 Bqm^-3, 361.93 Bqm^-3 and 3716.74 Bqm^-3 respectively. The average levels of water and indoor radon exceeded WHO's reference level of 100 Bqm^-3. Accordingly, the pilot national indoor radon reference level for Ghana is set as 200 Bqm^-3. (au)