Cadmium and lead concentrations in yerba mate leaves from agroforestry and plantation systems: An international survey in South America

Current legislation for Cd and Pb has been causing concern in the yerba mate production chain. An international survey was conducted to identify the relation of Cd and Pb concentration in yerba mate leaves with soil properties, geographic location, and agricultural management, and also to assess the exposure of humans to Cd and Pb when drinking yerba mate infusion. Paired yerba mate leaves and soil samples were collected on 115 farms from agroforestry and plantation systems in Brazil, Argentina, and Paraguay. We found correlations between available Cd in soil and yerba mate leaves, as well as between Cd and Zn foliar. Cultivation management adopted did not reflect differences in Cd and Pb concentrations between soils and the plant leaves. Cadmium in 21 % of the leaf samples (0.29 +/- 0.30 mg kg(-1)) were above the Cd threshold established for yerba mate leaves in South America (0.40 mg kg(-1)) and 38 % of leaf samples (0.61 +/- 0.40 mg kg(-1)) were above the Pb threshold of 0.60 mg kg(-1). The legal levels of Cd and Pb established for yerba mate leaves affect rather their trade than consumer health, as Cd and Pb intake estimated from yerba mate infusion were low.

Automated summary

Legislation concerning cadmium and lead levels in yerba mate production has raised concerns in the industry. An international survey found correlations between available cadmium in soil and yerba mate leaves, as well as between cadmium and zinc foliar. While some leaf samples exceeded legal thresholds for cadmium and lead, intake estimates from yerba mate infusion were found to be low for consumer health.