Dietary Trace Elements and Arsenic Species in Rice: A Study of Samples from Croatian Supermarkets

Rice (Oryza sativa L.) is a vital staple food and an important source of energy and macro- and micronutrients for billions of people. However, rice can accumulate undesirable levels of toxic trace elements, especially inorganic arsenic, which may pose a health risk. This study aimed to determine the concentrations of 29 essential and toxic elements and the fractions of four As species in 58 rice samples purchased in Croatian supermarkets. In addition, the influence of rice variety, cultivation methods, and origin on the composition of trace elements was analysed. The elements were quantified using inductively coupled plasma mass spectrometry (ICP-MS), and As species were quantified using high-performance liquid chromatography (HPLC) coupled with ICP-MS. Organic brown rice had higher concentrations of essential trace elements (Se, Zn, Cu, Fe, Mn, Co, Cr) than white rice, with organic brown rice containing more essential elements than conventionally grown rice. The average total arsenic concentration (tAs) across all samples was 142 ± 57 µg/kg, with brown, conventionally grown rice containing a higher amount. Arsenite was the predominant arsenic species. Regional differences in As and Se concentrations were observed. These results emphasize the complex relationship between trace elements in rice and their potential impacts on health.