Geographical distribution patterns of iodine in drinking-water and its associations with geological factors in Shandong Province, China.
County-based spatial distribution characteristics and the related geological factors for iodine in drinking-water were studied in Shandong Province (China). Spatial autocorrelation analysis and spatial scan statistic were applied to analyze the spatial characteristics. Generalized linear models (GLMs) and geographically weighted regression (GWR) studies were conducted to explore the relationship between water iodine level and its related geological factors. The spatial distribution of iodine in drinking-water was significantly heterogeneous in Shandong Province (Moran's I = 0.52, Z = 7.4, p < 0.001). Two clusters for high iodine in drinking-water were identified in the south-western and north-western parts of Shandong Province by the purely spatial scan statistic approach. Both GLMs and GWR indicated a significantly global association between iodine in drinking-water and geological factors. Furthermore, GWR showed obviously spatial variability across the study region. Soil type and distance to Yellow River were statistically significant at most areas of Shandong Province, confirming the hypothesis that the Yellow River causes iodine deposits in Shandong Province. Our results suggested that the more effective regional monitoring plan and water improvement strategies should be strengthened targeting at the cluster areas based on the characteristics of geological factors and the spatial variability of local relationships between iodine in drinking-water and geological factors.
Department of Epidemiology, School of Public Health, Fudan University, Shanghai 200032, China. agao1224@163.com.
Jie
J
Gao
Department of Epidemiology, School of Public Health, Fudan University, Shanghai 200032, China. epistat@gmail.com.
Zhijie
Z
Zhang
Department of Epidemiology, School of Public Health, Fudan University, Shanghai 200032, China. stevenhyy@163.com.
Yi
Y
Hu
Shandong Institute of Prevention and Control for Endemic Disease, Jinan 250014, China. bianjc1008@163.com.
Jianchao
J
Bian
Shandong Institute of Prevention and Control for Endemic Disease, Jinan 250014, China. shelloloh@126.com.
Wen
W
Jiang
Shandong Institute of Prevention and Control for Endemic Disease, Jinan 250014, China. booew@163.com.
Xiaoming
X
Wang
Department of Epidemiology, School of Public Health, Fudan University, Shanghai 200032, China. 13211020063@fudan.edu.cn.
Liqian
L
Sun
Department of Epidemiology, School of Public Health, Fudan University, Shanghai 200032, China. jiangqw@fudan.edu.cn.
Qingwu
Q
Jiang
D002681:China; D060766:Drinking Water / Q000032:analysis*; D004784:Environmental Monitoring; D005843:Geography; D019015:Geologic Sediments / Q000737:chemistry*; D007455:Iodine / Q000032:analysis*; D016014:Linear Models; D012044:Regression Analysis; D062206:Spatial Analysis; D013053:Spectrophotometry
D060766:Drinking Water; D007455:Iodine