Analysis of Mercury Content in Various Types of Tea (Camellia sinensis) and Yerba Mate (Ilex paraguariensis)

Due to the content of active ingredients, teas can be used prophylactically, but most of all they are consumed for taste reasons. As with food or water, these products can be contaminated with heavy metals, including mercury. Mercury (Hg) is a toxic element, it causes many side effects in the human body depending on the form of Hg, which can include respiratory failure, kidney damage, neurological disorders. At the cellular level, Hg and its compounds lead to a disturbance of metabolism and cell death. The aim of the study was to evaluate the mercury concentration of tea (Camellia sinensis) and Yerba Mate (Ilex paraguariensis). Eighty-six samples were collected and analyzed, including the following kinds: black, green, white, Pu-erh, and Yerba Mate. The samples came from Poland. The Hg concentration was determined with an AMA 254 atomic absorption spectrometer. The study showed that the Hg content in each tea sample averaged 2.47 μg/kg. The Hg concentration in the tested types of tea differed significantly statistically (p = 0.000). It was the largest in Yerba Mate, followed by green, Pu-erh, and white tea, and was the smallest in black tea. Statistically significant differences in the Hg content (p = 0.004) were also dependent on the form of the product; in leaf tea samples, the concentration of Hg (2.54 µg/kg) was higher than in tea bags (1.16 µg/kg). The Hg concentration determined in the tested samples does not exceed the permitted EU standard. Consuming these teas poses no health risk in terms of the amount of Hg.