Radionuclide Transfer in Tea Cultivation: Assessing Radiological Risks in the Largest and First Established Tea Garden in Bangladesh

ABSTRACT

To address potential health risks associated with radioactivity in tea consumption, a study was conducted utilizing high purity germanium (HPGe) γ-ray spectrometry to measure the concentrations of ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs radionuclides in soil and tea leaves collected from several major tea gardens (including the Malnicherra tea garden which is the largest and first established tea garden in the Indian subcontinent) situated in Sylhet, Bangladesh. Although nearly all soil samples showed the presence of ¹³⁷Cs (with a maximum activity of 6.5 ± 1.31 Bq/kg), none of the analyzed tea leaf samples exhibited its presence, which can be attributed to its restricted transferability from soil to plants. The range of transfer factors for ²²⁶Ra, ²³²Th and ⁴⁰K from soil to tea leaves was calculated to be (0.39–0.54), (0.25–0.46) and (1.39–3.03), respectively. The heightened concentrations of ⁴⁰K identified in the tea leaf samples can be mainly ascribed to specific metabolic processes associated with potassium, along with the heightened utilization of potassium chloride-based fertilizers aimed at enhancing tea production. The examination of hazard parameters, including the estimated committed effective dose and the excess lifetime cancer risk associated with tea consumption, reveals values that are comparatively lower than the recommended limits. Consequently, the radiation exposure from tea consumption does not present a significant radiological health concern for the general population.

KEYWORDS:

• Radioactivity
• tea leaves
• transfer factor
• HPGe
• health hazard

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

The collection of samples was carried out by [Md. Hossain Kamal]. Data preparation, data analysis, and data counting were carried out by [M.M. Mahfuz Siraz]. [M.M. Mahfuz Siraz], [Dr. Bazlar Rashid], [Jubair Al Mahmud], and [Mohammad Shafiqul Alam] authored the initial draft of the manuscript. The research was supervised by [Selina Yeasmin]. The total manuscript was reviewed by [Dr. Mayeen Uddin Khandaker], [Hamid Osman] and [Zulfiqar Hasan Khan]. The final manuscript was accepted by all writers.

Consent to participate

This study included neither experimental animals nor people as subjects.

Data availability statement

The datasets created and/or examined for this study are not publicly accessible, however they can be obtained from the corresponding author upon justifiable request.

Declarations

“All authors have read, understood, and have complied as applicable with the statement on “Ethical responsibilities of Authors” as found in the Instructions for Authors”.

Additional information

Funding

The authors extend their appreciation to Taif University, Saudi Arabia, for supporting this work through project number [TU-DSPP-2024-42].