Résumé:
The aim of this study is to evaluate the level of natural radioactivity in seven fertilizers from
two different regions, Constantine and Mila in Algeria, and in fertilized and unfertilized soil
samples collected at different depths in two pilot and private Algerian farms, from El-Athmania
and Ferdjioua, Mila, respectively. Using gamma spectroscopy with a hyper-pure germanium
detector (HPGe), a low background configuration and high-resolution.
The activity concentration ranges of 226Ra, 232Th and 40K in the soil samples were found at 23.72
± 2.37 «-ÿ 67.72 ± 7.77, 26.45 ± 0.78 <-ÿ 28.70 ± 0.90 and 178.5 ± 5.64 <-ÿ 290.1 ± 10.5 Bq.kg"
, respectively. The results of this current study have been compared with the world mean
values of 35, 30 and 400 Bq.kg"1, respectively, specified by the UNSCEAR (2000). The
artificial radionuclide, 137Cs was found in all measured soil samples and its mean activity was
2.66 Bq.Kg'1. Additionally, the vertical distribution of 137Cs soil activity concentrations was
studied in this current study. It can assumed from the results the decrease of 137Cs as a function
of depth.
i
Concerning radiological risk to human health, the absorbed gamma dose rate (D) in air is
estimated to be between 36.23 ± 0.4 and 58.78 ± 2.2 nGy.h'1; the outdoor annual effective dose
equivalent (DE) was evaluated to vary from 44.44 ± 0.4 to 69.88 ± 2.7 pSv.y'1, with the
arithmetic mean value of 61.43 ± 33.23 pSv.y"1, which is comparable to the worldwide effective
dose of 70 pSv.y"1. Also, the Raeq, Hex, Hm and Iy values for all soil samples in this work are
lower than the accepted safety limit of 370 Bq.kg'1 and below the unit limit, respectively. The
results indicate that the radiation hazard of primordial radionuclides in all soil samples of the
regions studied in this current work is not significant. On the other hand, the mean value of the
lifetime cancer risk factor for fertilizers studied is 9.45 x 10"4. Two (2) sampling points (FM
and TSP) have ELCR values greater than the worldwide average value. These results show that
lifetime cancer risk from exposure to these fertilizers for up to 70 years is high in both locations.
Therefore, subsequent use of this product for agriculture or for soil remediation studies and
other purposes should be discouraged.
