Status and regional distribution of areas with high iodine concentration in residents drinking water in Liaocheng City of Shandong Province / 中华地方病学杂志

ABSTRACT

Objective To investigate the distribution and characteristics of iodine excess areas in Liaocheng City of Shandong Province, and to provide data evidence for taking intervention measures. Methods From 2011 to 2013, 1 - 3 samples of drinking water were collected from all administrative villages in 8 counties (cities and districts) of Liaocheng.At the same time,1 sample of edible salt was collected from the household where water samples were collected. Arsenic and cerium spectrophotometry was used for the detection of water iodine and salt iodine was detected by semi-quantitative method. The region were divide according to the definition of "Water Source Excess Iodine Area and Excess Iodine Disease Area"(GB/T 19380-2016)and"Division of Iodine Deficiency Disorders Area"(GB 16005-2009).Results A total of 7 794 water samples were collected in 5 865 villages of 134 towns and the iodine median was 158.2 μg/L. The median of water iodine of 57 samples was less than 10 μg/L in drinking water and the ratio was 0.7%;2 286 samples were 10- 100 μg/L and the ratio was 29.3%; 5 451 samples were over 100 μg/L and the ratio was 69.9%. The towns with suitable water iodine (10 - 100 μg/L) and high water iodine ( > 100 μg/L) were 24.6%(33/134)and 75.4%(101/134), respectively, and no iodine deficiency town was found. The areas with high water iodine were distributed in patchy or foci. A total of 3 300 salt samples were collected,among them,iodized salt was 1 183(35.58%,1 183/3 300)and non-iodized salt was 2 117(64.15%,2 117/3 300). Among them, there were 36 towns with high iodine content and 20 towns with suitable iodine content, and the iodized salt coverage rates were 10.72% (225/2 099) and 79.77% (958/1 201),respectively.Conclusions The population of Liaocheng City is at risk of iodine excess.The high iodine areas coexists with suitable iodine areas.