Cadmium in potato and soybeans: Do phosphate fertilization and soil management systems play a role?

While it has been claimed that phosphate (P) fertilizers are essential for agriculture production, there is considerable debate regarding the safety of the cadmium (Cd) added to the soil in such fertilizers. Cadmium intake is a major concern in health risk assessments, and food ingestion represents a relevant route of exposure. Although the addition of P fertilizers might increase Cd contents in soils, its transfer to plants varies according to the management system. This work evaluated the Cd contents in potato cultivars receiving up to 560 kg P2O5 ha−1 and in soybeans cultivated under different management systems in soils with records of long-term applications of high doses of P fertilizers. Most of the Cd remained in the potato peels (23–781 μg kg−1 dry weight – DW) rather than in the tuber (14–43 μg kg−1 DW), and its values varied among cultivars and different areas. For soybeans, the Cd grain contents varied from 10 to 30 μg kg−1 DW for the experiment with crop rotation and 23–38 μg kg−1 DW in the soils receiving different liming rates. All the Cd contents found for the studied crops are in accordance with the Codex Alimentarius guidelines.