Assessment of arsenic in Australian grown and imported rice varieties on sale in Australia and potential links with irrigation practises and soil geochemistry

Abstract

Chronic dietary exposure to arsenic, particularly the inorganic forms (defined as elemental arsenic, predominantly As3+ and As5+, and all its inorganic compounds except arsine), is a matter of concern for human health. Ingestion of arsenic usually occurs via contaminated water but recent studies show there is also a risk of exposure from food, particularly Asian rice (Oryza sativa). Australia is a rice growing country, contributing around 2% of the world rice trade, and a large proportion of the population consumes rice regularly. In the present study we investigated concentrations of arsenic in both Australian grown and imported rice on sale in Australia and examined the potential links with irrigation practises and soil geochemistry. The results indicated a wide spread of arsenic levels of 0.09-0.33mgkg-1, with Australian grown Arborio and sushi varieties of O. sativa containing the highest mean value of ~0.22mgkg-1. Arsenic levels in all samples were below the 1mgkg-1 limit set by Food Standards Australia New Zealand.