Assessment of ten potentially toxic metal in tea leaves from selected tea gardens in southern Western Ghats, India

Abstract

Introduction

Tea is one of the world’s non-alcoholic and caffeinated beverages. However, elemental content will accumulate in the tea due to the excess use of growth nutrients and inorganic fertilisers during the tea planting process and instruments used in processing, which pose health risks to tea consumers. Therefore, we investigated potentially toxic ten metals (PTMs) in tea leaves from selected tea gardens in the Nilgiris and Anamalais, Southern Western Ghats, Tamil Nadu, India.

Methods

Fresh tea leaves were collected from six different tea gardens during pre- monsoon 2023; in each tea garden are 9 samples, and the overall collected samples are 54. The tea leaf samples were digested with concentrated nitric acid, sulphuric acid, and perchloric acid triacid mixture 9:2:1 as mentioned in APHA. The samples were then analysed for elemental content with the help of an ICP-MS, Perkin Elmer NexIon-300x and USA.

Results

The highest elemental content detected in Gudalur was Al- 14,716 mg g^-1, Fe - 3396.86 mg g^-1 and Mn- 955.77 mg g^-1. In the Valparai tea leaves, Fe-371.88 mg g^-1, Mn-584.01 mg g^-1 Ni-23.16 mg g^-1. Cd was detected in all the studied tea gardens and above the maximum permissible limit. Pb concentration exceeded in Udhagai and Gudalur. Additionally, Ni concentration is high in Kothagiri and Udhagai tea gardens.

Conclusion

The results of our study suggest taking action to monitor tea samples regularly to improve the quality of the tea crop production. This can be achieved by implementing strict regulations, promoting eco-friendly practices, and raising awareness about the harmful effects of PTMs for tea growers.