Abstract
This study focuses on the investigation of potential levels of heavy metals and natural radionuclides within both inorganic and organic fertilizers in Nigeria. The mean concentration of 40K activity in inorganic fertilizers was 566±0.36 Bqkg-1, ranging from 101.45 to 1033.60 Bqkg-1. The concentration range for 226Ra activity was 22.99 to 34.48 Bqkg-1, with an average of 28.36±1.96 Bqkg-1. For 232Th, the mean concentration was 57.33±0.7 Bqkg-1, spanning from 40.71 to 77.10 Bqkg-1. The air absorbed dose rate varied between 53.91 and 144.90 nGyh-1, with a mean of 72.31 nGy h-1, surpassing the global average of 51 nGyh-1. The annual effective dose rate averaged at 88.37 µSvy-1 (0.088 mSvy-1), ranging from 60.51 to 178.23 µSvy-1. The calculated Raeq averaged 134 Bqkg-1, falling below the 370 Bqkg-1 threshold for radiation hazards. The Hex and Hin values averaged 0.48 and 0.39, respectively, ranging from 0.398 to 0.83 and 0.29 to 0.77.
In the context of organic fertilizers, the average 40K activity concentration was 305.33±0.196 Bqkg-1, with a range of 120 to 907 Bqkg-1. The average concentration for 232Th was 45.04 Bqkg-1, spanning from 14.66 to 60.20 Bqkg-1. The 226Ra concentration averaged 24.87±0.02 Bqkg-1, with a range of 12.83 to 65.69 Bqkg-1. The average air absorbed dose rate was 51.59 nGyh-1, ranging from 30.33 to 101.23 nGyh-1. The annual effective dose rate averaged 61.33 µSvy-1 (0.061), lower than the global average (0.07 µSvy-1), and ranged from 33.39 to 124.51 µSvy-1. The calculated Raeq for organic fertilizers was 112.90 Bqkg-1, well below the 370 Bqkg-1 maximum. Hex and Hin values for organic fertilizers averaged 0.31 and 0.37, respectively.
From a radiological standpoint, organic fertilizers exhibit minimal radiological risk, as indicated by low hazard indices compared to global averages. Elemental analysis of inorganic fertilizers revealed the presence of several metals, including Cd, Cu, Fe, Zn, Mn, and Ti. Additionally, certain fertilizers contained Cr, Si, and K. All inorganic fertilizers exhibited at least 13 heavy metals in their composition. Among organic fertilizers, various metals such as Cd, Cu, Fe, Ni, Zn, and Mn were found, along with Cr, As, Co, Si, and Ti in specific cases. Some organic fertilizers contained Cs and Sb. Although the environmental presence of these elements doesn’t pose an immediate threat due to concentrations within typical soil levels, ongoing environmental monitoring is essential to prevent cumulative element buildup.
EXPLORING ELEMENTAL AND RADIOLOGICAL ANALYSIS OF SELECTED INORGANIC AND ORGANIC FERTILIZERS IN NIGERIA, GET MORE, ACTUARIAL SCIENCE PROJECT TOPICS AND MATERIALS
