内蒙古托克托县潜水与承压水中氟化物的空间分布特征及形成机理

氟是维持人体健康所必需的微量元素，过多或过少的摄入都会造成相应的健康问题。本研究从氟的来源、迁移和富集等角度，揭示了内蒙古呼和浩特市托克托县高氟地下水的空间分布规律及其在潜水和承压水中富集的原因。对研究区60个水样(30个潜水和30个承压水)进行了统计分析、水化学特征研究、聚类分析以及相关性分析。结果表明：潜水中F^- 浓度为0.40~7.20(2.30±1.80) mg/L，承压水中F^- 浓度为0.29~12.70(1.67±2.48) mg/L；地下水中F-浓度与HCO^-₃、Na⁺、溶解性总固体(TDS)和电导率(EC)呈正相关，与Ca²⁺呈一定的负相关关系。高氟水的水化学类型主要为HCO₃·Cl-Na型。受地下水流场的控制，高氟潜水(>5 mg/L)主要分布在地下水的排泄区；承压水中F^- 的富集主要受含水层岩性的影响，氟高浓度(>1.5 mg/L)分布区主要集中在研究区南部的湖积台地区域。

The Spatial Distribution and Its Formed Mechanism of Fluoride in the Unconfined and Confined Groundwater of Tuoketuo County,Inner Mongolia

Insufficient or excessive intake of fluoride can create health problems for humans. The objective of this study was to understand the occurrence of fluoride in groundwater as well as its spatiotemporal variation and reasons in Tuoketuo County, Hohhot, Inner Mongolia, in view of the factors influencing the sources, migration and enrichment of fluorine. Sixty water samples(30 phreatic and 30 confined sources) were conducted a statistical analysis, water chemistry characteristics analysis, cluster and correlation analysis. The fluoride concentration in water samples varied from 0.40 to 7.20 (2.30±1.80) mg/L and 0.29-12.70(1.67±2.48)mg/L in phreatic and confined water, respectively. An analysis of the hydrogeochemical characteristic of samples indicated that the high fluoride content of groundwater was caused by the alkaline environment with high levels of TDS, HCO^-₃, Na⁺, EC and with a Ca²⁺ deficiency. High F^- concentrations were mainly observed in ground-water of HCO₃·Cl-Na type. The highest concentration of fluoride (>5 mg/L) in phreatic water was located in the groundwater discharge area because this water was affected by the groundwater flow field. In confined aquifers, the concentration of fluoride was mainly controlled by lithology; a high fluoride content (>1.5 mg/L) was only observed in lacustrine platform zone in confined aquifers in the study area.