Objective:To study the spatial distribution and characteristics of iodine content in residential drinking water in Shaanxi Province, and provide a basis for scientific prevention and control of iodine deficiency disorders.Methods:From March to October 2022, an investigation was conducted in all counties (districts, referred to as counties) of Shaanxi Province, with administrative villages as survey units. For centralized water supply systems, two terminal water samples were collected, and iodine content was measured separately, with the average value representing the drinking water iodine content at that location. For decentralized water supply systems, a 10% sampling method was used to divide each administrative village into five areas (east, south, west, north, and center), with 10% of water wells sampled from each area (if fewer than 10 water wells, the well with the largest drinking population was selected; if fewer than 5 wells, all wells were sampled). One water sample was collected from each water well, and iodine content was determined using the arsenic-cerium catalytic spectrophotometry method. Spatial autocorrelation and spatial scan analysis were used to analyze the spatial distribution and characteristics of drinking water iodine content.Results:A total of 53 990 drinking water samples were collected, with a median water iodine content of 6.66 μg/L, ranging from 0.10 to 779.40 μg/L. Drinking water iodine content was detected in 112 counties, showing a significant spatial positive correlation (global autocorrelation, Moran's I = 0.74, Z = 43.83, P < 0.001). Local autocorrelation analysis showed that the difference in the distribution of iodine content in drinking water among 36 counties was statistically significant ( P < 0.05), with 22 counties showing low-low clustering and 12 counties showing high-high clustering. Spatial scanning identified three water iodine clustering areas, including two high-water iodine cluster areas and one low-water iodine cluster area. Conclusions:The distribution of iodine content in residential drinking water in Shaanxi Province shows significant spatial clustering and heterogeneity, requiring targeted interventions to achieve precise prevention and control of iodine deficiency disorders.

Objective To investigate iodine content in drinking water and clarify the distribution characteristics of iodine in water in Shaanxi Province.Methods A cross-sectional survey method was used to collect water samples from administrative villages in the province.Two tap water samples were taken from the centralized water supply villages,and 10％samples were taken from the decentralized water supply villages.Water iodine was detected by arsenic cerium catalytic spectrophotometry.Water iodine areas were divided according to national standards:＜40 μg/L was iodine deficiency area,40-100 μg/L was iodine adequate area,＞100 μg/L was high iodine area.According to the ecological regionification scheme of the Chinese Academy of Sciences,Shaanxi Province was divided into three types:the central and eastern Inner Mongolia Platea-Loess Plateau ecological region,the Fenwei Basin ecological region,and the Qinba Mountains ecological region.SPSS 25.0 was used for statistical analysis.Results The median of water iodine in Shaanxi Province was 6.66 μg/L.The survey of water iodine content was conducted in 22 848 administrative villages,1 309 townships,112 counties and 14 municipalities in the whole province.The median water iodine was less than 40 μg/L in 91.75％(20 963/22 848)of the administrative villages,between 40 and 100 μg/L in 7.40％(1 691/22 848)of the administrative villages,and more than 100 μg/L in 0.85％(194/22 848)of the administrative villages.The median of water iodine in the central and eastern Inner Mongolia Platea-Lose Plateau ecological zone,the Fenwei Basin ecological zone,and Qinba Mountains ecological zone was 12.35,8.88,and 2.00 μg/L,respectively,and the differences among different ecological zones were statistically significant(H=6 616.23,P＜0.001).The median of water iodine of centralized and decentralized water supply was 6.72 and 6.21 μg/L,respectively,and differences between different water supply methods were statistically significant(Z=5.638,P＜0.01).Conclusion The overall external environment of Shaanxi Province is iodine deficient,and most of the administrative villages are iodine deficient areas.There are a certain proportion of high iodine water source areas and suitable iodine areas.

Objective:To study the spatial distribution and characteristics of iodine content in residential drinking water in Shaanxi Province, and provide a basis for scientific prevention and control of iodine deficiency disorders.Methods:From March to October 2022, an investigation was conducted in all counties (districts, referred to as counties) of Shaanxi Province, with administrative villages as survey units. For centralized water supply systems, two terminal water samples were collected, and iodine content was measured separately, with the average value representing the drinking water iodine content at that location. For decentralized water supply systems, a 10% sampling method was used to divide each administrative village into five areas (east, south, west, north, and center), with 10% of water wells sampled from each area (if fewer than 10 water wells, the well with the largest drinking population was selected; if fewer than 5 wells, all wells were sampled). One water sample was collected from each water well, and iodine content was determined using the arsenic-cerium catalytic spectrophotometry method. Spatial autocorrelation and spatial scan analysis were used to analyze the spatial distribution and characteristics of drinking water iodine content.Results:A total of 53 990 drinking water samples were collected, with a median water iodine content of 6.66 μg/L, ranging from 0.10 to 779.40 μg/L. Drinking water iodine content was detected in 112 counties, showing a significant spatial positive correlation (global autocorrelation, Moran's I = 0.74, Z = 43.83, P < 0.001). Local autocorrelation analysis showed that the difference in the distribution of iodine content in drinking water among 36 counties was statistically significant ( P < 0.05), with 22 counties showing low-low clustering and 12 counties showing high-high clustering. Spatial scanning identified three water iodine clustering areas, including two high-water iodine cluster areas and one low-water iodine cluster area. Conclusions:The distribution of iodine content in residential drinking water in Shaanxi Province shows significant spatial clustering and heterogeneity, requiring targeted interventions to achieve precise prevention and control of iodine deficiency disorders.

Objective To investigate iodine content in drinking water and clarify the distribution characteristics of iodine in water in Shaanxi Province.Methods A cross-sectional survey method was used to collect water samples from administrative villages in the province.Two tap water samples were taken from the centralized water supply villages,and 10％samples were taken from the decentralized water supply villages.Water iodine was detected by arsenic cerium catalytic spectrophotometry.Water iodine areas were divided according to national standards:＜40 μg/L was iodine deficiency area,40-100 μg/L was iodine adequate area,＞100 μg/L was high iodine area.According to the ecological regionification scheme of the Chinese Academy of Sciences,Shaanxi Province was divided into three types:the central and eastern Inner Mongolia Platea-Loess Plateau ecological region,the Fenwei Basin ecological region,and the Qinba Mountains ecological region.SPSS 25.0 was used for statistical analysis.Results The median of water iodine in Shaanxi Province was 6.66 μg/L.The survey of water iodine content was conducted in 22 848 administrative villages,1 309 townships,112 counties and 14 municipalities in the whole province.The median water iodine was less than 40 μg/L in 91.75％(20 963/22 848)of the administrative villages,between 40 and 100 μg/L in 7.40％(1 691/22 848)of the administrative villages,and more than 100 μg/L in 0.85％(194/22 848)of the administrative villages.The median of water iodine in the central and eastern Inner Mongolia Platea-Lose Plateau ecological zone,the Fenwei Basin ecological zone,and Qinba Mountains ecological zone was 12.35,8.88,and 2.00 μg/L,respectively,and the differences among different ecological zones were statistically significant(H=6 616.23,P＜0.001).The median of water iodine of centralized and decentralized water supply was 6.72 and 6.21 μg/L,respectively,and differences between different water supply methods were statistically significant(Z=5.638,P＜0.01).Conclusion The overall external environment of Shaanxi Province is iodine deficient,and most of the administrative villages are iodine deficient areas.There are a certain proportion of high iodine water source areas and suitable iodine areas.