Fluoride-leaching simulation of aquifer sediment and its influence on groundwater fluoride levels along coastal plains
C. P. Jia,
Q. Chen,
M. G. An,
C. L. Zhi,
S. W. Lou,
P. P. Zhang,
Q. C. Li,
Y. M. Zhang,
S. Y. Han,
H. T. Zheng
Affiliations
C. P. Jia
College of Science, China University of Petroleum (East China), Qingdao 266580, China
Q. Chen
Shandong Provincial Key Laboratory of Depositional Mineralization & Sedimentary Minerals, College of Earth Science & Engineering, Shandong University of Science and Technology, Qingdao 266590, China
M. G. An
Shandong Provincial Lunan Geology and Exploration Institute (Shandong Provincial Bureau of Geology and Mineral Resources No.2 Geological Brigade), Yanzhou 272100, China
C. L. Zhi
Shandong Provincial Lunan Geology and Exploration Institute (Shandong Provincial Bureau of Geology and Mineral Resources No.2 Geological Brigade), Yanzhou 272100, China
S. W. Lou
The Fourth Exploration Team of Shandong Coal Geology Bureau, Weifang 261200, China
P. P. Zhang
Shandong Institute of Geophysical & Geochemical Exploration, Jinan 250013, China
Q. C. Li
Shandong Provincial Lunan Geology and Exploration Institute (Shandong Provincial Bureau of Geology and Mineral Resources No.2 Geological Brigade), Yanzhou 272100, China
Y. M. Zhang
Shandong Provincial Lunan Geology and Exploration Institute (Shandong Provincial Bureau of Geology and Mineral Resources No.2 Geological Brigade), Yanzhou 272100, China
S. Y. Han
Shandong Provincial Lunan Geology and Exploration Institute (Shandong Provincial Bureau of Geology and Mineral Resources No.2 Geological Brigade), Yanzhou 272100, China
H. T. Zheng
Shandong Provincial Lunan Geology and Exploration Institute (Shandong Provincial Bureau of Geology and Mineral Resources No.2 Geological Brigade), Yanzhou 272100, China
Seawater intrusion and drinking-water fluorosis are frequently documented along coastal plains. Groundwater is characterized by high OH−, Na+, total dissolved solids, and low Ca2+ because of seawater intrusion, and such conditions favor sediment fluoride-leaching and fluorosis. But the geological process of seawater intrusion has not been noticed when high-fluoride groundwater along coastal areas is discussed. The groundwater and sediments in a typical seawater intrusion and fluorosis area are gained, and fluoride-leaching simulation experiments are performed. Sediment fluoride levels are equal to or lower than average sediment fluoride levels in China and Shandong province, but strong fluoride-leaching in aquifers is observed. Compared with the supplied water from the non-intruded neighboring area, the local groundwater has higher fluoride levels, together with higher pH, total dissolved solids, HCO3−, Cl−, Br−, SO42−, Na+, K+, and low Ca2+ because of seawater intrusion. Aquifer sediment fluoride-leaching ability increases with an increase in seawater (brine water) mixing ratios, and NaCl or NaHCO3 levels, but with a decrease in CaCl2 levels. This directly confirms that seawater (brine water) intrusion promotes sediment fluoride-leaching, and the high pH, Na+, HCO3−, and low Ca2+ levels caused by seawater intrusion are responsible for the high-fluoride groundwater along coastal plains. HIGHLIGHTS The local groundwater is characterized by seawater intrusion and high fluorine levels, while the aquifer sediments show low fluorine levels.; The fluorine-leaching ability of aquifer sediments increases with higher ratios of seawater or brine water, higher levels of NaCl and NaHCO3, and lower levels of CaCl2.; Seawater intrusion is an important dynamic of groundwater fluorine enrichment along coastal plains.;
