Assessment of heavy metals, PAHs, and pesticide levels in yerba mate on the European market

Although yerba mate has been known and used for hundreds of years, not all of its properties have been fully understood yet. Yerba mate is a source of many desirable substances, but it may also contain toxic metals and other substances that are harmful to health. Fifteen samples of yerba mate tea from three South American countries were analyzed. The content of Cr, Ni, and Cd was determined using the AAS technique, while the PHA’s content was determined with the gas chromatography method. Our studies show that some of the analyzed substances present in Ilex paraguariensis may exceed their acceptable levels specified in European standards established for the given substances. All analyzed samples contained the determined metals, where the concentrations of individual elements ranged from 1.92 ± 0.38 to 0.12 ± 0.05 µg/g (for Cr), from 4.86 ± 0.28 to 1.72 ± 0.14 µg/g (for Ni), and from 0.0008 ± 0.000 to 0.0695 ± 0.0745 µg/g (for Cd). The total PAH content ranged from 0.064 to 0.585 mg/kg. Yerba mate samples from Brazil were characterized by a lower PAH content (0.064–0.254 mg/kg), compared with mate from Argentina and Paraguay (0.084–0.374 and 0.197–0.585 mg/kg, respectively). Pesticide residues were found only in samples from Argentina and Paraguay, while samples from Brazil did not contain those compounds. Only four active substances belonging to the group of herbicides, fungicides, and insecticides were detected, two of them not approved for use in the EU: chlorpyrifos and fenbuconazole. The most frequently detected compounds in yerba mate samples were pendimethalin (in four samples), fluazifop-p-butyl and fenbuconazole (detected in two samples), and chlorpyrifos (in one sample).