Arsenic: bioaccessibility from seaweed and rice, dietary exposure calculations and risk assessment

Abstract

Arsenic is a metalloid that occurs in food and the environment in different chemical forms. Inorganic arsenic is classified as a class I carcinogen. The inorganic arsenic intake from food and drinking water varies depending on the geographic arsenic background. Non-dietary exposure to arsenic is likely to be of minor importance for the general population within the European Union. In Europe, arsenic in drinking water is on average low, but food products (e.g. rice and seaweed) are imported from all over the world including from regions with naturally high arsenic levels. Therefore, specific populations living in Europe could also have a high exposure to inorganic arsenic due to their consumption pattern. Current risk assessment is based on exposure via drinking water. For a good estimation of the risks of arsenic in food, it is important to investigate if the bioavailability of inorganic arsenic from food is different from drinking water. The present study further explores the issue of European dietary exposure to inorganic arsenic via rice and seaweed and its associated health risks. The bioavailability of inorganic arsenic was measured in in vitro digestion experiments. The data indicate that the bioavailability of inorganic arsenic is similar for rice and seaweed compared with drinking water. The calculated dietary intake for specific European Union populations varied between 0.44 and 4.51 µg kg^–1 bw day^–1. The margins of exposure between the inorganic intake levels and the BMDL_0.5 values as derived by JECFA are low. Decreasing the intake of inorganic arsenic via Hijiki seaweed could be achieved by setting legal limits similar to those set for rice by the Codex Alimentarius Commission in July 2014.

Keywords:

• bioavailability
• organic arsenic
• inorganic arsenic
• arsenite
• arsenate

Acknowledgement

This investigation was performed by order, and for the account of, the Ministry of Health, Welfare and Sport of the Netherlands. The authors would like to thank GALAB laboratories for performing the analysis of As and its different species. Furthermore, they thank RIKILT – Institute of Food Safety (part of Wageningen University and Research Centre) – for performing the in vitro digestion experiments; and Hans Verhagen (National Institute for Public Health and the Environment) for his help with the intake calculations. In addition, the authors thank Gerrit Wolterink (National Institute for Public Health and the Environment) for his critical input during the preparation of this article. This investigation was performed by order, and for the account of, the Dutch Ministry of Health, Welfare and Sport. The authors have no financial or personal relationships with people or organisations that could influence (bias) their work.