Evaluation of metal accumulation in the forage grass Brachiaria decumbens Stapf grown in contaminated soils with iron tailings

Abstract

The biggest world tailing dam rupture occurred in Brazil in 2015, releasing approximately 32 million m3 of iron tailings in the Doce River watershed, along its 660 km trajectory, reaching the Atlantic Ocean. This disaster significantly altered water and soil properties, increasing the soil metal contents, mainly iron concentration. Little is known about the concentration of toxic elements in plants grown in these areas. Brachiaria decumbens stands out as the most cultivated grass in the affected areas and is widely used for cattle grazing. This study verified the metal contents in soils and in samples of B. decumbens grown in the initial pathway of the debris flow. It was noted that the tailing deposition altered the substrate chemically, increasing Fe by 181% and reducing Zn soil contents by 188%. However, the metal contents in the forage grass were below the toxic limit for cattle feed. In addition, the results suggest that the natural geological characteristics of the region also influenced the metal contents in plants since those plants grown in nonaffected areas also showed high metal concentrations. The impacted area soils had a slightly basic pH, which can reduce the metal availability. Considering that, in the future, these soils would return to their natural acid state, the metal contents in plants grown in the affected regions could probably increase. Thus, long‐term studies are needed to ensure the food safety of the forage production in these areas. Integr Environ Assess Manag 2022;18:528–538. © 2021 SETAC

Leachate characteristics, dry matter yield of Urochloa decumbens and properties of two contrasting soils irrigated with sludgewater in columns

“…A reduction in fertility status of the soil and dry conditions can lead to reduced productivity and so the grass also benefits from irrigation through both nutrient and moisture availability. Although signal grass is sensitive to salinity, in contrast to other perennial grass species (Deifel et al., 2006), it has adaptive characteristics that enable it to survive in metal contaminated soils (Ferreira et al., 2021). The grass has medium tolerance to Mn allowing high levels in the shoot without causing visual symptoms of toxicity (Puga et al., 2012).…”

MsNRAMP2 Enhances Tolerance to Iron Excess Stress in Nicotiana tabacum and MsMYB Binds to Its Promoter

“…Transporters are involved in the absorption, transportation, redistribution, and detoxification of iron in plants. Dicotyledonous alfalfa belongs to the iron uptake strategy I, in which Fe 3+ is reduced to the form of Fe 2+ by Ferric reduction oxidase (FRO) [14] and absorbed by the iron-regulated transporter (IRT) [15]. Natural resistance-associated macrophage proteins (NRAMPs) are a class of metal transporters widely present in plants.…”