Arsenic in cereals, their relation with human health risk, and possible mitigation strategies

ABSTRACT

Arsenic (As) contamination of edible plants is now well recognized mainly in Bangladesh, India, and some other countries of South and Southeast Asia and Latin America. It is well known that long-term use of As-contaminated irrigation water adds As to soils and edible plants to adversely affect food production and quality. Consolidated evidence shows that As uptake in edible plants and crops is proportionally associated with the presence of high As in soils and irrigation waters. However, factors such as cultivation method, As speciation, soil composition, origin, and type of plant have major impact on the amount of As uptake. When As is absorbed by crops and edible plants, this may add substantially to the dietary As intake, thus posing human health risks to local inhabitants and to places where the As-contaminated food is exported. To date, limited attention has been paid to the risk of consumption of As-contaminated foods. In this context, our aim was to review As uptake in some of the common and popular cereals that have been a cause of human health risk. We also reviewed possible mitigation options and what needs to be done in the future.

KEYWORDS:

• Arsenic
• cereal
• crop
• grain
• health risk

Acknowledgments

The authors thank Md Soriful Islam, Department of Experimental and Clinical Medicine, Faculty of Medicine, Università Politecnicadelle Marche, Italy, for critically reviewing the manuscript. The authors also thank Mr. Sanowar Hossain Faruque for extensively editing the manuscript.

Notes

² Arsenite [As (III)] is a chemical compound containing an As oxyanion where As has oxidation state +3. As(III) is 25–60 times more toxic and mobile than arsenate [As(V)].

³ Bangladesh Rice Research Institute (BRRI) works to develop the varieties and production of rice for the sustainable food security.

⁴ At moderate or high redox potentials, arsenic can be stabilized as pentavalent [As(V)]. In plant cells, As (V) is rapidly reduced to As(III).

⁵ Roxarsone is an organoarsenic compound that is widely used in poultry production as a feed additive to increase weight gain and improve feed efficiency.

⁶ Arsanilic acid, also known as aminophenyl arsenic acid or aminophenyl arsonic acid, is an organoarsenic compound.

⁷ DMA (dimethylarsinic acid) is a major form of As in the environment as well as being used as a general herbicide or pesticide. Moreover, DMA is one of the major methylated metabolites of ingested organic or iAs in most mammals, including humans.^(159,160)

⁸ The arsM gene has been identified as bacterial and archaeal homologs of arsenic (+3 oxidation state) methyltransferase. In transgenic rice plant, this gene has the capability for methylating iAs to a variety of organic species, including volatile arsenicals.

⁹ Aquaporins are integral membrane proteins from a larger family of major intrinsic proteins that form pores in the membrane of biological cells.

¹⁰ ABC transporters (ATP-binding cassette transporters) are members of a transport system superfamily that is one of the largest families with representatives in all extant phyla from prokaryotes to humans.

¹¹ Phytochelatins act as chelators, and are important for heavy metal detoxification.