Investigation of iodine level in drinking water in iodine, deficiency areas in Shandong province

Objective To look into the current distribution of iodine deficiency area in Shandong province and to guide the re-defined iodine deficiency area and to supplement iodine scientifically. Methods In 2008, 100 iodine deficiency counties（cities, districts）, designated in Shandong province＇s ＂to supplement iodized salt to eliminate the hazard of iodine deficiency management regulations＂, were selected in the study. One to three samples were collected from water source which was used by the majority of local residents in the 100 iodine deficiency places and iodine concentration was tested by As3＋-Ce4＋ catalyzing spectrophotometry. Results A total of 65 716 water samples were collected. Sample recovery efficiency reached 99.8%（65 572/65 716）. The median water iodine was 5.57 μg/L, with 82.05%（ 1097/1337 ） of the township（town） met criteria for the classification of iodine deficiency areas（water iodine 〈 10 μg/L）, 17.43%（233/1337） of the township （town） water iodine moderate（water iodine 10 - 150 μg/L）, and 0.52%（7/1337）of the township（town） should be defined high iodine areas（water iodine 〉 150 - 300 μg/L）. Conclusions The iodine deficiency areas should be redefined because water iodine concentrations of iodine deficiency areas have changed. We suggest that the smallest place to supply salt with different range of iodine content is set to the township（town）. Key words: Iodine;  Deficiency diseases;  Drinking;  Data collection