State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an 710069, China.
State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an 710069, China; Xi'an Key Laboratory of Multiple Energy Resources Exploration and Development, Xi'an 710069, China.
J Hazard Mater. 2024 Dec 5;480:136468. doi: 10.1016/j.jhazmat.2024.136468. Epub 2024 Nov 12.
The enrichment of fluoride in the deep geothermal water of the Lantian - Bahe Formation in parts of the Weihe Basin in China is a potential health hazard for the millions of inhabitants of this region. We conducted hydrochemical and hydrogeological analyses of water samples from 31 geothermal wells in the Weihe Basin, with the aims of determining the distribution characteristics, enrichment patterns, hydrochemical processes, and the factors influencing the geochemistry of deep geothermal fluids. We also evaluated the potential health hazards of fluoride ions in these fluids. Our results show that geothermal fluids with high fluoride content are widely distributed in the deep aquifers of the Weihe Basin. The principal hydrochemical types are: HCO-Na and SO⋅HCO⋅Cl-Na. We used hydrodynamic simulation and regression analysis to show that the high proportion of HCO in the geothermal water facilitates the precipitation of Ca and the dissolution of fluorine-bearing minerals. The high temperature, alkaline environment, cation exchange reactions, and dissolution and precipitation processes lead to Ca depletion, which facilitates the release of fluoride ions from the surrounding rocks into the geothermal fluids. A human health risk assessment shows that the hazard quotient (HQ) values of geothermal water for adult males, adult females, children, and infants are: 3.96 - 14.41 (median 6.55), 3.32 - 12.08 (median 4.50), 4.63 - 16.84 (median 5.50), and 7.48 - 27.22 (median 9.00), respectively. Infants are the most susceptible to the effects of high fluoride in groundwater due to their physiological characteristics. while the potential health risks of F for children and adult women/men are relatively low. Therefore, in the process of developing deep geothermal water, it is necessary to prevent it from mixing into shallow drinking water as much as possible. If the fluoride ion content in the shallow water exceeds the standard, it may have an impact on the local environment and residents' health. These findings provide a scientific foundation for the effective management of high fluoride groundwater in the Weihe Basin and analogous regions elsewhere.
中国渭河流域蓝田-灞河组深部地热水中氟的富集对该地区数百万居民的健康构成了潜在威胁。我们对渭河流域 31 口地热井的水样进行了水文地球化学和水文地质分析，目的是确定深部地热流体的分布特征、富集模式、水文地球化学过程以及影响其地球化学性质的因素。我们还评估了这些流体中氟离子的潜在健康危害。研究结果表明，渭河流域深部含水层中广泛分布着高氟含量的地热流体。主要的水化学类型为：HCO-Na 和 SO⋅HCO⋅Cl-Na。我们利用水动力模拟和回归分析表明，地热水中高比例的 HCO 有利于 Ca 的沉淀和含氟矿物的溶解。高温、碱性环境、阳离子交换反应以及溶解和沉淀过程导致 Ca 耗尽，从而促进了氟离子从周围岩石向地热流体中的释放。人体健康风险评估表明，地热水中氟对成年男性、成年女性、儿童和婴儿的危害系数（HQ）值分别为：3.96-14.41（中位数 6.55）、3.32-12.08（中位数 4.50）、4.63-16.84（中位数 5.50）和 7.48-27.22（中位数 9.00）。由于生理特点，婴儿对地下水高氟的影响最敏感，而儿童和成年女性/男性受 F 的潜在健康风险相对较低。因此，在开发深部地热水资源的过程中，应尽可能防止其混入浅层饮用水。如果浅层水中的氟离子含量超标，可能会对当地环境和居民健康产生影响。这些发现为渭河流域及其他类似地区高氟地下水的有效管理提供了科学依据。
