@proceedings{AnaCatarinaPereiraSimões2014,
	month={september},
	note={Arsenic (As) is a metalloid that occurs naturally in soils and groundwater. Contamination of rice (Oryza sativa) with As has become a global concern. Rice is an essential food source for the world population, including Portugal which is the largest consumer in Europe, per capita. The growth conditions of the rice plant allow the accumulation of arsenic in both plant and grain which may be a route for the intake of this element by consumers. In anaerobic conditions, As is mainly present the form of arsenite (As III), the more toxic form and the one that preferentially accumulates in the grain [1].
This study was conducted with 21 samples of rice and rice products available in the Portuguese market in which we determined the levels of total arsenic by electrothermal atomic absorption spectrophotometry (ETAAS). The obtained rice samples originated from Portugal, other European countries and from Asia.
In samples of milled rice originating from Europe and Asia, the average content of As ranged from 12.0 ± 5.5 to 300.8 ± 31.8 mg kg-1. The highest As content was found in Portuguese rice in varieties japonica (“carolino”) and Indica (“agulha”). The oriental varieties, thai jasmine and basmati showed the lowest levels of As in the grain. These results suggest that geographical origin and variety can influence the levels of As in rice grain. Only one sample of rice “carolino” had a score higher than that recommended by FAO/WHO (300 mg kg-1 DW) for the rice grain [2], all the other samples being below this value.
Based on the levels of As found in the analysed Portuguese rice samples and on the average rice consumption in Portugal (16.1 kg person-1 year-1 [3]), a value of daily intake of As was estimated: 0.17 to 0.23 mg kg-1 day-1 for a person of 60 kg. These results are within the range defined for a European consumer (0.13 to 0.56 mg kg-1) [4], suggesting that the values obtained are not significant in terms of potential consequences for public health. However, special attention should be paid to risk groups such as children and celiacs, whose diet is based on rice.
Regarding the rice products, we analysed 3 wafer samples, 4 rice flour samples and 4 samples of other rice products (rice and corn sticks, rice sheets, rice-based breakfast cereals and rice drink). The results indicate the presence of arsenic, but the concentration depends on multiple factors, such as the percentage of rice in the product mix, geographical origin and variety of rice, and production and processing methods. The highest levels of As were found in one type of rice flour (400.5 ± 27.9 mg kg-1 DW). 
Generally, in all the rice products analysed, the values were lower than the indicated limits, although by a small margin in some cases. Nonetheless the levels of As must be constantly monitored in rice products from all origins to guarantee that the limits are not exceed and that the food chain is not contaminated.},
	organization={Sociedade Portuguesa de Quimica, ISA},
	title={Evaluation of the levels of arsenic in rice and rice products available in the Portuguese market},
	year=2014,
}