Gross alpha and beta activities and trace heavy elemental concentration levels in chemical fertilizers and agricultural farm soils in Nigeria

The gross alpha (α) and beta (β) activities and trace heavy elemental concentrations have been determined in Single Super Phosphate (SSP) and Nitrogen Phosphorous Potassium (NPK) fertilizers samples used for agricultural purposes in Nigeria. Cultivated farm soil samples from two regions (north and south) in the country and samples of phosphate rocks were also analyzed for gross α and β radioactivity and elemental concentrations. The beta activity concentration in the NPK (15-15-15) fertilizers was found to vary from 2410.0 ± 80.0 Bq·kg to 4560 ± 140.0 Bq·kg, between 1340.0 ± 70.0 Bq·kg and 1440.0 ± 70.0 Bq·kg in the Single Super phosphate fertilizers while in the farm soil it ranged between 360.0 ± 40.0 Bq·kg to 570.0 ± 50.0 for the north samples and 200.0 ± 50.0 to 230.0 ± 20 Bq·kg for the south samples. The alpha activities in the NPK fertilizers was found to vary from 20.0 ± 10.0 to 90.0 ± 20.0 Bq·kg, in the SSP it varied from 60.0 ± 20.0 to 100.0 ± 20.0 Bq·kg while in the soil samples it varied from 8.0 ± 6.0 to 40.0 ± 10.0 Bq·kg (north) and 10.0 ± 10.0 to 20.0 ± 10.0 Bq·kg (south). The trace heavy metal concentration in Phosphate rock samples, SSP and the NPK (15-15-15) fertilizers samples were lower than the safety limits, however, the heavy elements were all detected in NPK fertilizers samples including Hg.