Analysis of the Presence of Toxic Metals in Yerba Mate Samples: a Case Study from South Brazil

The presence of toxic metals in soil enables them to be absorbed by plants. The RDC 42/2013 published by Brazilian Health Regulatory Agency (ANVISA) defines the maximum values of cadmium (0.4 mg kg −1 ) and lead (0.6 mg kg −1 ) in yerba mate commercialized in Common Market of the South (Mercosul). This work is a retrospective study that aimed to evaluate cadmium and lead levels in processed yerba mate and in natura leaves in Southern Brazil. The cadmium and lead concentrations in 370 processed yerba mate and 122 in natura leave samples obtained in Southern Brazil were analyzed. In 47.56% of the processed samples, the levels of cadmium and/or lead were found to be above the authorized levels. The cadmium levels found in the processed yerba mate were 0.37 ± 0.19 mg kg −1 , and the corresponding values for lead were 0.34 ± 0.21 mg kg −1 . Values above the authorized levels were also found in the non-processed leaves. Studies are required to determine whether these levels are natural or represent contamination.