One of the three goals of the United Nations
for sustainable food security is to ensure that all people
have access to sufficient, nutritionally adequate, and
safe food. Decades of tin mining in the Bitsichi area of
the Jos Plateau, Nigeria, have left a legacy of polluted
water supplies, impoverished agricultural land, and soil
containing abnormally high levels of naturally occurring
radioactive elements. In order to ascertain the
radiological food safety of the population, different
crops that constitute the major food nutritive requirements
were collected directly across farmlands in the
area. The activity concentrations of 226Ra, 228Th, and
40K were determined in the food and soil samples using
c-ray spectrometry. Additionally, in situ gamma dose
rate measurements were performed on the farms using
a pre-calibrated survey meter. The corresponding
activity concentrations in the food crops ranged from
below detection limit (BDL) to 684.5 Bq kg–1 for 40K,
from BDL to 83.5 Bq kg–1 for 226Ra, and from BDL to
89.8 Bq kg–1 for 228Th. Activity concentrations of these
radionuclides were found to be lower in cereals than in
tubers and vegetables. As for the soil samples, activity
concentrations of these radionuclides varied from BDL
to 166.4 Bq kg–1, from 10.9 to 470.6 Bq kg–1, and from
122.7 to 2,189.5 Bq kg–1 for 40K, 226Ra, and 228Th,
respectively. Average external gamma dose rates were
found to vary across the farms from 0.50 ± 0.01 to
1.47 ± 0.04 lSv h–1. Due to past mining activities, the
soil radioactivity in the area has been modified and the
concentration level of the investigated natural radionuclides
in the food crops has also been enhanced.
However, the values obtained suggest that the dose
from intake of these radionuclides by the food crops is
low and that harmful health effects are not expected.