Source and transport enrichment mechanism of iodine in shallow saline groundwater in Tianjin coastal area

Iodine is one of the essential trace elements in the human body, and excessive or insufficient intake will affect human health. To ensure the safety of drinking water resources, the spatial distribution of iodine content and migration enrichment factors in shallow underground salty water in Tianjin coastal area were studied. The results show that the iodine (as I − ) content of shallow groundwater ranges from not detected (ND) to 1320 μg/L, and high iodine groundwater (100–300 μg/L) and super-high iodine groundwater (> 300 μg/L) account for 37.5% of the groundwater samples, distributed in the east, west, central and south of the study area; iodine-deficient groundwater (