Arsenic speciation in Brazilian rice grains organically and traditionally cultivated: Is there any difference in arsenic content?

Inorganic arsenic contamination in rice is a global public concern due to the risks associated. In spite of being an important issue, few studies concerning differences between inorganic arsenic in rice grains under organic and conventional methods of cultivation are available in Brazil, which is an important producer and consumer. In the present work, samples of polished and husked rice (organic and conventional) and gastronomic rice (Arborio, Carnaroli and red/black rice) were analyzed and the results compared to FAO/Codex maximum limits. The total determination and speciation analysis of arsenic were carried out by ICP-MS and HPLC-ICP-MS, respectively. The results showed no significant statistical differences in total As concentration in organic rice (157.7±56.1ngg-1) vs. conventional rice (137.4±46.6ngg-1) and also in organic husked rice (227.7±95.5ngg-1) vs. conventional husked (217.7±60.9ngg-1). However, inorganic As was 45% higher in organic polished rice than in conventional polished rice and 41% higher in organic husked rice than in conventional husked rice. Gastronomic rice presented total arsenic ranging from 65.4 to 348ngg-1 for black and Arborio rice, respectively. Regarding the maximum levels adopted by Codex for i-As (200ngg-1), no violation was found.