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The lead (Pb) isotopes Pb-206 and Pb-208 are the final products of the radioactive decay of U-238 and Th-232, respectively. Soils in the municipalities of Pedra and Venturosa, Brazil, present high levels of these radionuclides. We hypothesized that forage plants growing in these soils may take up high amounts of Pb and, consequently, intoxicate dairy cows. To test this, we quantified Pb concentrations in 23 forage samples from this region. Pb concentrations varied from 5 to 344 mg kg(-1). The highest values are one order of magnitude above the reported limit, therefore, indicating high risk of Pb contamination for dairy cows.