Comparison of the Radioactivity Level of Bird’s Eye Chilli in Chemical and Natural Fertilizers

Abstract

Background: Concerns regarding naturally occurring radionuclides in agricultural inputs have increased due to their potential transfer into food crops. This study evaluates the activity concentrations of K-40, Th-232, and Ra-226 in chemical and natural fertilizers and examines their subsequent uptake in Bird’s Eye chilli to assess radiological safety. Methods: Twelve samples comprising chemical fertilizers, natural fertilizers and bird’s eye chilli were collected and analyzed using a High Sensitivity Gamma Spectrometer GDM 10C equipped with WinDAS software. Activity concentrations of the selected radionuclides were quantified, and further assessments of radium equivalent activity (Ra_eq), absorbed dose rate, and annual effective dose were performed. Data processing and comparative analyses were conducted using Microsoft Excel. Results: All three radionuclides were detected in both fertilizer types. Activity concentrations in fertilizers ranged from 1.3329×10?? to 6.3679×10?? Bq/kg, while bird’s eye chilli samples showed higher values ranging from 3.9453×10?? to 9.7137×10?? Bq/kg. Chemical fertilizers exhibited higher radioactivity indicators, with average Ra_eq (3.6147 Bq/kg), absorbed dose rate (1.6472 nGy/h), and annual effective dose (0.0202 mSv) compared to natural fertilizers (1.7146 Bq/kg, 0.7941 nGy/h, and 0.0097 mSv, respectively). Correspondingly, chillies grown with chemical fertilizers showed a higher annual ingestion dose of K-40, Th-232, and Ra-226. Conclusion: Although radioactivity levels were higher in samples influenced by chemical fertilizers compared to natural fertilizers, all measured doses remained well below the public exposure limit of 1 mSv/year. Therefore, the bird’s eye chilli samples analyzed in this study are considered radiologically safe for human consumption.