Assessment of Activity Concentration and Transfer Factor of Radionuclides in Fluted Pumpkin Cultivated with and without Inorganic Fertilizer

The study examines the activity concentration (AC) of naturally occurring radionuclides and the extent of transfer of these radionuclides from soil to fluted pumpkin leaves. The study was carried out for fluted pumpkin cultivated with and without the use of inorganic fertilizers. The mean AC obtained for fluted pumpkin leaf samples cultivated with inorganic fertilizer were 43.50 ± 3.02 Bq/kg, 16.02 ± 1.18 Bq/kg, 29.11 ± 1.51 Bq/kg and 1324.92 ± 72.62 Bq/kg for 238U, 226Ra, 232Th and 40K respectively. While the mean concentration obtained for fluted pumpkin leaf samples cultivated without inorganic fertilizer were 43.50 ± 2.03 Bq/kg, 16.02 ± 1.27 Bq/kg, 29.11 ± 1.58 Bq/kg and 1324.92 ± 70.09 Bq/kg for 238U, 226Ra, 232Th and 40K respectively. The transfer factor (TF) from soil to the fluted pumpkin cultivated with inorganic fertilizers, for 238U ranges from 0.013 to 1.049 with a mean of 0.572. For 226R, 232Th and 90K, the transfer factors ranges from 0.338 to 1.140 with a mean of 0.549, 0.130 to 1.480 with a mean of 0.734 and 26.679 to 309.92 with a mean of 83.879 respectively. In this study the mean AC for 238U, 226R and 232Th are higher than the recommended limits for both fluted pumpkin leaf samples cultivated with and without inorganic fertilizer.The transfer factor of 238U in location (1.049) is more than the recommended limit of 1. Also, the transfer factors of 226R from soil to the fluted pumpkin in locations (1.001) and (1.140) are all above the recommended values. The mean TF values obtained for 238U, 226Ra and 232Th in this work were lower than unity which is the world recommended value. The TF for 40K was however greater than 5.60 which is the world recommended value. For fluted pumpkin cultivated without inorganic fertilizers, the transfer factors for 238U, 226R, 232Th and 90K from the soil to the fluted pumpkin, ranges from 0.028 to 2.010, 0.334 to 1.219, 0.333 to 1.859 and 21.374 to 165.411 respectively. The transfer factors for 238U, 226R, 232Th and 90K in location F18 are all above the recommended values. It is observed that fluted pumpkin cultivated with inorganic fertilizers, has the highest TFs. This may be related to the morphological characteristics of the plants such as higher weight and size of fluted pumpkin leaves which allows a high amount of the radionuclides to be collected and accumulated.