RESUMO
Rare earth elements (REE) are a group of chemical elements that include lanthanoids (lanthanum to lutetium), scandium and yttrium. In the last decades, the REE demand in the industry and other areas has increased significantly. In general, REE have shown low concentrations in soils, plants, water and atmosphere, but they may accumulate in such environments due to anthropogenic inputs. In areas where there is REE contamination, the slow accumulation of these elements in the environment could become problematic. Many studies have shown environmental areas contaminated with REE and their toxic effects. Thus, it is important to review, in order to improve the current understanding of these elements in the environment, showing the effects of REE exposure in mining, soil, water, plants and food. Besides, there are few suppliers and a limited quantity of these elements in the world. This paper suggests options to improve the sustainability management of REE chain.
Assuntos
Conservação dos Recursos Naturais , Metais Terras Raras , Animais , Monitoramento Ambiental , Poluentes Ambientais/análise , Contaminação de Alimentos/análise , Humanos , Metais Terras Raras/análiseRESUMO
This work focuses on the determination of chemical elements in sweet oranges of variety Valencia produced under organic and conventional systems using instrumental neutron activation analysis and inductively coupled plasma mass spectrometry. The distribution of chemical elements was variable among the fruit parts with usually higher concentrations of Br, Ca, Ce, K, La, Na, Rb, and Sc in the peel. However, K, Na, and Rb also presented high values in the juice samples, while Fe and Zn were higher in the seeds. Differences between organic and conventional oranges were found for Br and Cu.
Assuntos
Citrus sinensis/química , Alimentos Orgânicos/análise , Oligoelementos/análise , Bebidas/análise , Frutas/química , Espectrometria de Massas , Análise de Ativação de Nêutrons , Sementes/químicaRESUMO
Arsenic (As) and chromium (Cr) contents were measured in agricultural supplies used at different farms in Sao Paulo State, Brazil. The highest mass fractions of As were found in thermophosphates, reaching levels of 4 mg/kg. The highest mass fractions of Cr (21 g/kg) were found in calcium magnesium silicate, while the thermophosphates also presented high values reaching approximately 1 g/kg. The levels of As were within Brazilian guidelines, but the values of Cr in thermophosphates exceeded the levels permitted in Brazil. The As content in fertilizers may be considered safe (<5 mg/kg) in terms of environmental pollution. However, the Cr content in calcium magnesium silicate following continuous use may constitute a significant problem in Brazil due to potentially increasing levels of this metal in soils.