High natural bromine concentrations in organic Brazil Nuts from Bolivia

Commercial Brazil Nuts (Bertholletia excelsa) are known for their highly unusual elementome (i.e., the totality of elements in an organism), which includes anomalous selenium, barium, and radionuclide concentrations. Brazil Nut is also abnormal in containing high bromine (Br) concentrations frequently exceeding legislatory maximum residue level (MRL) thresholds. This study sought to determine if the high Br concentrations in Brazil Nuts are of natural origin or derived from methyl bromide fumigation or other contamination. Our analysis shows that the high prevailing concentration of Br in Brazil Nut appears to be a consequence of this species having evolved an enhanced ability to accumulate Br from the soil. Existing thresholds or the chlorine/bromine ratio are not useful for differentiating natural and synthetic sources of Br in Brazil Nut.