An environmental approach to correcting iodine deficiency: supplementing iodine in soil by iodination of irrigation water in remote areas.
OBJECTIVE
Iodine deficiency disorders continue to be a severe problem in many parts of Central Asia, causing delayed mental development and cretinism in indigenous populations. In some areas, iodized salt has not succeeded in controlling this problem. In southern Xinjiang Province of China, we tried a new method of supplying iodine to rural populations by dripping potassium iodate into irrigation water canals. By this means iodine was distributed into soil, crops, animals and people. This proved feasible and cost effective; it reached all the people, required no medical expertise, required no continuing effort after the initial dripping, and had the important added benefit of improving livestock production.


METHODS
We serially monitored iodine concentrations in soil, crops, animal products and human urine for several years after the last dripping. In a similar project in Inner Mongolia, total soil iodine was determined in addition. Here, iodine concentrations in soil, crops, animals and people have been monitored for 4 years after supplementation.


RESULTS
After dripping, total iodine increased two-fold, while soluble iodine increased 4-5-fold. Iodine added to soil is available for more than 4 years after a single application.


CONCLUSIONS
Potassium iodate added to soil appears to increase soluble iodine out of proportion to the amount added. This effect and the long persistence of dripped iodate in soil contribute to the efficacy and cost effectiveness of this method of iodine supplementation.
Ren
Qiang
Q
Institute of Population Research, Peking University, Beijing 100871, PR China. renqiang@pku.edu.cn
Fan
Jie
J
Zhang
Zhizhong
Z
Zheng
Xiaoying
X
Delong
G Robert
GR
D000293:Adolescent; D000328:Adult; D000383:Agriculture; D000818:Animals; D002648:Child; D004784:Environmental Monitoring; D005260:Female; D006801:Humans; D007452:Iodates / Q000378:metabolism; D007455:Iodine / Q000032:analysis / Q000172:deficiency* / Q000652:urine; D017680:Potassium Compounds / Q000378:metabolism; D012987:Soil / Q000032:analysis; D014881:Water Supply / Q000032:analysis
D007452:Iodates; D017680:Potassium Compounds; D012987:Soil; D007455:Iodine; C039693:potassium iodate