Investigation results of iodine in drinking water in Henan Province from 2017 to 2020 / 中华地方病学杂志

ABSTRACT

Objective:To investigate the iodine content in drinking water of residents in Henan Province, and clarify the distribution characteristics of water iodine in Henan Province.Methods:In 2017, in all counties (cities and districts, hereinafter referred to as counties) of Henan Province, taking township (town, subdistrict office, hereinafter referred to as township) as the unit to carry out an investigation of iodine content in drinking water; and in the township with water iodine content of 10 μg/L or more, taking administrative village (neighborhood committee, hereinafter referred to as the administrative village) as the unit to carry out the drinking water iodine content investigation. Supplementary investigation was conducted from 2018 to 2020 in administrative villages where water iodine levels had never been tested or had not been tested after replacing water sources. At least 25 ml water samples were collected at each sampling site, and the water iodine content was determined by cerous sulfate catalytic spectrophotometry.Results:From 2017 to 2020, the median water iodine in Henan Province was 8.20 μg/L. A total of 50 124 administrative villages in 2 465 townships, 160 counties and 18 provincial-level cities were investigated for iodine content in drinking water, of which 65.5% (32 807/50 124) of the administrative villages had a median water iodine < 40 μg/L, belonging to iodine deficiency area; 16.9% (8 473/50 124) of the administrative villages had a median water iodine of 40-100 μg/L, suitable for iodine; and 17.6% (8 844/50 124) of the administrative villages had a median water iodine > 100 μg/L, belonging to water source high iodine area.Conclusions:Henan Province as a whole is at the state of iodine deficiency in the external environment. Most administrative villages are iodine deficiency areas. There are certain proportion of water source areas with high iodine and areas with suitable iodine.