Productivity and food safety of grain crops and forage species grown in iron ore tailings

The rupture of the Fundao dam (Minas Gerais, Brazil) released a large amount of iron ore tailings, which raised concerns about possible impacts on local agricultural activity. Given this scenario, this study evaluated the productivity and the accumulation of metals to verify if food safety would be compromised in four species of great relevance in the region, two grain crops (bean and maize) and two forage species (braquiaria and crotalaria), cultivated in iron ore tailings and in soil. The tailings showed higher levels of Fe, Mn and Na than the soil. The productivity of bean, crotalaria and maize in the tailings did not differ from that in soil. Braquiaria plants had reduced growth when grown in tailings. With the exception of braquiaria, Fe and Mn were the main metals in higher concentrations in the shoot of plants grown in the tailings. The concentrations of metals detected in bean and maize grains were within the limits allowed for human consumption and do not offer long-term risks, indicating food safety. The results presented here suggest the viability of the resumption of agricultural activity with these species in the region impacted by the iron ore tailings from the rupture of the Fundao dam.