Dynamics of Environmental Repletion of Iodine

Abstract

Southern Xinjiang province of the People’s Republic of China is an area of severe iodine deficiency. The people, who are Uygurs, China’s largest minority group, are rural, poor, isolated, and self-subsistent on iodine-deficient desert land entirely dependent on irrigation (1). We previously reported studies from the Hotien region of southern Xinjiang describing the parameters of iodine deficiency disease, indicating that 8–11 Yo of infants have definite neurological deficits and 25–30% have microcephaly, attributable to iodine deficiency (2). Soil iodine content is in the range of 7–32 µg/kg; water iodine 1–1.5 µg/L, and urine iodine excretion in some villages has a median value less than 10 µg/L, the lower limit of measurement. Usual methods of iodine supplementation have failed, including iodized salt, injection of iodine in oil, and oral iodine-in-oil capsules, because of distribution difficulties, cost, suspicions by some people that the supplements contained contraceptives, and the preference of the population for their traditional source, rock salt from the desert floor, which is low in iodine. Faced with these difficulties, we devised a method of providing iodine to the population by adding iodine to irrigation water in order to increase iodine content of soil, crops, domestic animals, and the people.