A Dietary Risk Assessment for Indigenous Consumption of Natural Salt Deposits in the Darhad Valley, Northern Mongolia

ABSTRACT

The nomadic herding population of the Darhad Valley, in northern Mongolia, collects and utilizes a salt precipitate, called hujir, which develops at the saline system, Tohi. This culturally important indigenous dietary supplement is consumed daily as an ingredient in a salty milk-tea and because of its essential micro- and macronutrients it is a beneficial and necessary part of their daily diet. Despite its benefits, there are increasing health concerns among the Darhad people as a result of consuming hujir. Therefore, we conducted a dietary risk assessment. Consumption rates were obtained from interviews with nomadic herders of the valley and a chronic exposure assessment was completed using chemical analyses on hujir samples. A combination of chronic toxicity threshold values, dietary reference intake recommendations, and drinking water guidelines were used to estimate dietary risks related to hujir consumption. Exposures to arsenic, fluoride, and nitrate were as high as 33, 1.2, and 1.3 times the chronic oral reference dose, respectively. Exposures to antimony, arsenic, and lead were 1.7, 19, and 14 times the drinking water guidelines, respectively. Given these results, additional studies are needed to better understand possible health effects associated with hujir consumption in the Darhad population, especially for arsenic.

Key Words:

• arsenic exposure
• indigenous salt source
• nomadic population
• Mongolia
• dietary risk assessment

ACKNOWLEDGMENTS

We thank the people of the Darhad Valley for their cooperation, the Mongolian translators (Khongorzul Mendbayar, Sunjidmaa Tsagaan, and Otgonsuren Avirmed), and the Institute of Geoecology for their help in Mongolia. We also thank BioRegions Programs for funding the study and R. Macur and D. Morse for technical assistance.

Notes

¹The study was exempted by the Montana State University's Institutional Review Board (IRB) from the requirement of IRB review in accordance with the Code of Federal Regulations, Part 46, section 101.

^amg/kg body weight/day;

^b95th percentile exposure;

^cOral reference dose;

^dUncertainty factor;

^eRisk quotient;

^fLowest observed adverse effect level;

^gNo observed adverse effect level;

^hValue = benchmark dose, low (BMDL₅₀) and benchmark dose (BMD₅₀), respectively;

ⁱNot available through WHO and/or USEPA.

^amg/kg body weight/day;

^b95th percentile exposure;

^cOral reference dose;

^dRisk quotient;

^eLowest observed adverse effect level;

^fNo observed adverse effect level;

^gValue = benchmark dose, low (BMDL₅₀) and benchmark dose (BMD₅₀), respectively;

^hNot available through WHO and/or USEPA.

^amg/day;

^b95th percentile exposure;

^cDietary reference intakes;

^dRisk quotient;

^eTolerable upper level intake;

^fNot available.

^amg/l;

^bNumbers in parenthesis are 95th percentile exposures (mg/l);

^cRisk quotient.