Arsenic and cadmium contents in Brazilian rice from different origins can vary more than two orders of magnitude.

Brazil is a major producer of rice, but there is not enough information about As and Cd in rice grown under different conditions in this country. Here, As and Cd were determined by ICP-MS and species of As by HPLC-ICP-MS in Brazilian husked rice, covering diverse cultivars and regions, as well as upland and flooded production systems. Significant differences were observed for contents of both elements according to the origin of rice. All samples were below the maximum limit for Cd (400 µg/kg) set by national legislation, while nine samples presented total As above the legislation limit (300 µg/kg). From 24 samples analyzed for As species, 42% showed iAs above the European limit for production of food to infants (100 µg/kg). The total As content in samples from Mato Grosso state presented a maximum value of 6 µg/kg, which combined with low Cd content make interesting further studies.

Trace element measurement for assessment of dog food safety.

The quality of dog diets depends on adequate ingredients capable of providing optimal nutrition and free of contaminants, for promoting long-term health. Trace elements in 95 samples of dry food for dog puppies (n = 32) and adults (n = 63) of various brands were measured using instrumental neutron activation analysis (INAA). The mass fractions of most elements were within the permissible limits for dogs. Aluminum, antimony, and uranium presented fairly high levels in some samples, which may imply health risks. Aluminum mass fractions ranged from <21 to 11,900 mg/kg, in same brand, super-premium dog food. Antimony mass fractions ranged up to 5.14 mg/kg, with the highest values measured in six samples of dog food from the same producer. The mass fractions of uranium was found up to 4 mg/kg in commercial brands from five different producers.

Chemical elements in organic and conventional sweet oranges.

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.

Analytical quality in environmental studies: uncertainty evaluation of chemical concentrations determined by INAA

A análise por ativação neutrônica instrumental (INAA) é uma técnica analítica de alto nível metrológico para a determinação de elementos químicos. No contexto do programa BIOTA/FAPESP, folhas de árvores vêm sendo avaliadas empregando-se INAA para a biomonitoração da Mata Atlântica. Para garantir a comparabilidade dos resultados em estudos ambientais, amostra de folhas de Marlierea tomentosa, cujas concentrações de elementos químicos obtidas foram as menores, foi selecionada para a avaliação da qualidade analítica na mais desfavorável situação. Esta avaliação levou em consideração a homogeneidade das concentrações de elementos e a estimativa da repetitividade analítica. Embora a homogeneidade das concentrações tenha sido detectada em nível de 95% de confiança e a INAA tenha apresentado repetitividade estimada em 2% para Br, Co, Cs, Fe, K, Na, Rb e Sr, a incerteza pode ter sido superestimada. Para a avaliação da incerteza devido à variabilidade das concentrações químicas na amostra, os métodos Jackknife e Bootstrap foram empregados para estimar o desvio padrão máximo esperado. A estimativa de incerteza foi considerada adequada para a geração de resultados de concentrações químicas em estudos ambientais.