Arsenic speciation in rice bran: Agronomic practices, postharvest fermentation, and human health risk assessment across the lifespan

Annika M Weber; Bridget A Baxter; Anna McClung; Molly M Lamb; Sylvia Becker-Dreps; Samuel Vilchez; Ousmane Koita; Frank Wieringa; Elizabeth P Ryan

doi:10.1016/j.envpol.2021.117962

Arsenic speciation in rice bran: Agronomic practices, postharvest fermentation, and human health risk assessment across the lifespan

Environ Pollut. 2021 Dec 1:290:117962. doi: 10.1016/j.envpol.2021.117962. Epub 2021 Aug 12.

Authors

Annika M Weber¹, Bridget A Baxter², Anna McClung³, Molly M Lamb⁴, Sylvia Becker-Dreps⁵, Samuel Vilchez⁶, Ousmane Koita⁷, Frank Wieringa⁸, Elizabeth P Ryan⁹

Affiliations

¹ Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO 80523, USA; Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
² Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
³ USDA-Agricultural Research Service, Dale Bumpers National Rice Research Center, Stuttgart, AR 72160, USA.
⁴ Department of Epidemiology and Center for Global Health, University of Colorado School of Public Health, Aurora, CO 80045, USA.
⁵ Departments of Family Medicine and Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7595, USA.
⁶ Center of Infectious Diseases, Department of Microbiology and Parasitology, Faculty of Medical Sciences, National Autonomous University of Nicaragua, León (UNAN-León), León, Nicaragua.
⁷ Laboratoire de Biologie Moléculaire Appliquée, Campus de Badalabougou, Université des Sciences, des Techniques et des Technologies de Bamako, BP: 1805, Bamako, Mali.
⁸ Alimentation, Nutrition, Santé (E6), UMR95 QualiSud, University of Montpellier, Avignon Université, CIRAD, Institut Agro, Institut de Recherche pour le Développement (IRD), Université de La Reunion, Montpellier, France.
⁹ Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA. Electronic address: E.P.Ryan@colostate.edu.

Abstract

Arsenic (As) exposure is a global public health concern affecting millions worldwide and stems from drinking water and foods containing As. Here, we assessed how agronomic practices and postharvest fermentation techniques influence As concentrations in rice bran, and calculated health risks from consumption. A global suite of 53 rice brans were tested for total As and speciation. Targeted quantification of inorganic As (iAs) concentrations in rice bran were used to calculate Target Hazard Quotient (THQ) and Lifetime Cancer Risk (LCR) across the lifespan. Mean iAs was highest in Thailand rice bran samples (0.619 mg kg^-1) and lowest in Guatemala (0.017 mg kg^-1) rice bran samples. When comparing monosodium-methanearsonate (MSMA) treated and the Native-soil counterpart under the irrigation technique Alternate Wetting and Drying (AWD) management, the MSMA treatment had significantly higher total As (p = 0.022), and iAs (p = 0.016). No significant differences in As concentrations were found between conventional and organic production, nor between fermented and non-fermented rice bran. Health risk assessment calculations for the highest iAs-rice bran dosage scenario for adults, children and infants exceeded THQ and LCR thresholds, and LCR was above threshold for median iAs-rice bran. This environmental exposure investigation into rice bran provides novel information with food safety guidance for an emerging global ingredient.

Keywords: Arsenic; Food safety; Health risk assessment; Inorganic arsenic; Rice bran; Speciation.

MeSH terms

Adult
Arsenic* / analysis
Child
Fermentation
Food Contamination / analysis
Humans
Infant
Longevity
Oryza*
Risk Assessment

Substances

Arsenic