Drinking-water fluorosis is universal along coastal zones, and the seawater or brine water intrusion is occasionally supposed to enrich groundwater fluorine levels. However, there is no conclusive proof, and the laws and mechanisms remain ambiguous. Granite, the common fluorine-bearing rock, is selected and experimented upon to reveal the characteristics and laws of fluorine's leaching ability during the intrusion of seawater. The fluorine-leaching ability increases with the increasing ratios of seawater or brine water, the increasing levels of NaCl or NaHCO₃, and the decreasing levels of CaCl₂. Such results directly confirm that seawater or brine water intrusion, as well as the conditions of higher Na⁺, HCO₃⁻ and lower Ca²⁺, promotes fluorine-leaching ability from granite. The intensities of SiOSi, SiOFe, SiOAl bonds decrease but those of OH bonds increase with a higher ratio of seawater or brine water, the higher levels of NaCl or NaHCO₃, and the lower levels of CaCl₂. This indicates the more silicate dissolution and stronger OH-F exchange evoked by seawater or brine water intrusion are responsible for the higher fluorine-leaching from granite. Therefore, the process of seawater or brine water intrusion should be important for the groundwater enrichment dynamics along coastal zones.

饮用水氟中毒在沿海地区普遍存在，有时海水或盐水的入侵会增加地下水中的氟含量。但是，没有确凿的证据，法律和机制仍然不明确。花岗岩是常见的含氟岩石，经过选择和试验，揭示了氟在海水入侵过程中的浸出能力特征和规律。氟的浸出能力随海水或盐水的比例增加，NaCl或NaHCO ₃含量的增加以及CaCl ₂含量的降低而增加。这样的结果直接证实，海水或盐水的水的侵入，以及较高的Na的条件⁺，HCO ₃ ^-Ca ²⁺较低，促进了花岗岩中氟的浸出能力。随着海水或盐水的比例越高，NaCl或NaHCO ₃的含量越高，CaCl _2的含量越低，Si O Si，Si O Fe，Si O Al键的强度降低，但OH键的强度升高。这表明海水或盐水入侵引起的硅酸盐溶解量增加和OH-F交换更强，这是导致花岗岩中氟含量较高的原因。因此，海水或盐水的侵入过程对于沿岸地区的地下水富集动态应该是重要的。