Assessing mineral and toxic elements content in rice grains grown in southern Brazil

The development of rice genotypes with higher mineral content and less accumulation of toxic elements can help to mitigate problems related to mineral deficiency and insure consumption of safe foods. However, genetic improvement depends on the presence of genetic diversity. Therefore, here we characterize a rice panel, grown in southern Brazil, regarding iron (Fe), zinc (Zn), selenium (Se), manganese (Mn), copper (Cu), arsenic (As), cadmium (Cd) and lead (Pb) content in irrigated system with permanent flooding. The environment of each harvest season significantly influenced Cu, Zn, Se, Fe and Mn content in rice grains. None of the analyzed rice genotypes can meet the daily recommendation of Fe and Zn, being the highest contents detected for these mineral of similar to 17 and similar to 27 mg kg(-1), respectively. We detected genotypes able to supply Mn, Cu and Se demand, and genotypes accumulating similar to 37, similar to 5, similar to 0.200 mg kg(-1) were detected, respectively. None of the analyzed genotypes showed Cd and Pb accumulation above the Brazilian allowed limits. However, As content was above of the allowed limit for most of the studied accessions, and some genotypes reached 1 mg kg(-1) of As in their grains. Among the genotypes, low genetic diversity was detected for the evaluated elements.

Automated summary

The study found that the environment and harvest season significantly influenced the levels of copper, zinc, selenium, iron, and manganese in rice grains. None of the analyzed rice genotypes met the daily recommendations for iron and zinc, with the highest detected levels being around 17 mg/kg and 27 mg/kg, respectively. Some genotypes could provide manganese, copper, and selenium within acceptable limits, but arsenic levels were often above the allowed limit.