Groundwater iodine has direct importance for human dietary iodine intake in areas where drinking water is of groundwater origin. However, little is known about enrichment and mobilization mechanisms of groundwater iodine in the North China Plain (NCP). Geochemistry, inorganic/organic carbon isotope and biomarker of groundwater and sediment samples were studied to reveal the effects of depositional environment and organic matter (OM) degradation on the generation of high iodine groundwater (>100 μg/L) in NCP. Results showed that groundwater iodine had a range of 7.2–800 μg/L and was increasing with increase in HCO₃ concentration and decrease in groundwater δ¹³C_DIC value, indicating the potential effects of microbial activity on the elevation of groundwater iodine. Sediments iodine ranged from 0.03 to 2.54 μg/g and higher contents occurred under the oxidizing depositional environment (higher Pr/Ph ratios). Biomarker analysis indicated that the marine iodine-rich OM is considered as the main source of groundwater iodine, which is prone to be released into groundwater by the microbial degradation under the reducing conditions. The hypothesis was evidenced by the ¹³C_org, ¹³C_DIC and 3-D excitation emission matrices of groundwater. These results suggest that carbon-related biogeochemical cycling and redox condition are important in the enrichment and mobilization of iodine in groundwater system.

在饮用水源于地下水的地区，地下水碘对人类饮食碘的摄入具有直接的重要性。然而，对于华北平原（NCP）地下水碘的富集和动员机制知之甚少。研究了地球化学，无机/有机碳同位素以及地下水和沉积物样品的生物标志物，以揭示沉积环境和有机物（OM）降解对NCP中高碘地下水（> 100μg/ L）的生成的影响。结果表明，地下水碘有范围的7.2-800微克/升，并用在HCO增加是增加₃浓度和减小地下水δ ¹³ C ^ _DIC值，表明微生物活动对地下水碘升高的潜在影响。沉积物中碘的含量范围为0.03至2.54μg/ g，在氧化沉积环境下（较高的Pr / Ph比），碘含量较高。生物标志物分析表明，富含海洋碘的OM被认为是地下水碘的主要来源，在还原条件下，微生物降解易将其释放到地下水中。地下水的¹³ C _org，¹³ C _DIC和3-D激发发射矩阵证明了这一假设。这些结果表明，与碳有关的生物地球化学循环和氧化还原条件对地下水系统中碘的富集和迁移具有重要意义。