| Water is a precious resource for human survival,groundwater is the main source of water for agriculture,industry,and drinking for residents in the dry northern regions.Fuyang is the most populous city in Anhui Province,relying mainly on groundwater for drinking and industrial use.The quality of groundwater directly affects the health of residentsand long-term consumption of highly mineralized and fluorinated groundwater poses significant health risks to local residents.Therefore,studying the hydrochemical characteristics,water quality status and their impact on human health in Fuyang’s centralized groundwater drinking water source is of great significance for the rational development and utilization of groundwater and the protection of residents’ drinking water health.This study utilized various technical methods,such as data collection and assessment,field investigation,sample collection,data analysis,hydrogeochemistry,and technical means,combined with theoretical knowledge such as geology,petrology,mineralogy,statistics,hydrogeology,and hydrogeochemistry.This study investigated the hydrogeological conditions,water quality status,and distribution of surrounding pollution sources of 234 centralized groundwater drinking water sources in Fuyang City.A total of 42 typical centralized groundwater drinking water sources were screened as key research objects,and their water chemical characteristics and typical ion enrichment characteristics were systematically assessed.The study systematically analyzed their hydrochemical and typical ion enrichment characteristics.It revealed the formation mechanism of hydrochemical components,clarified the genesis and influencing factors of typical ions,and evaluated water quality status and health risk levels.Through indoor experimental simulations,CeCl3modified chlorella biochar(Ce-CB)was prepared.A variety of techniques,including’X-ray photoelectron spectroscopy(XPS),X-Ray Diffraction(XRD),Scanning Electron Microscopy-Energy Dispersive X-Ray Spectrometry(SEM-EDS),Fourier transform-infrared spectroscopy(FT-IR),and pore structure analysis,were appliedto conduct fluoride removal experiments in groundwater.The adsorption mechanism was further elucidated.Additionally,the existing fluoride removal device for groundwaterwas improved,which could automatically configure the corresponding regenerationsolution by achieving the stable recycling of activated alumina and improving fluoride removal efficiency.The main achievements obtained are as follows:1.The centralized underground water source in Fuyang City is slightly alkaline and neutral,with high mineralization and a chemical type of HCO3-Na.The distribution of mineralization,fluoride ions,and boron ions shows a trend of being high in the north and low in the south.The vertical distribution of fluoride and boron ions increases with the depth of the aquifer.The spatial distribution characteristics of iron and manganese ions are consistent,but their vertical distribution decreases with the depth of the aquifer.The enrichment of iron,manganese,fluoride,and boron is mainly controlled by the original sedimentary environment and geological conditions and is also affected by climate,hydrogeological conditions,chemical type,and pH value.2.Methods such as Gibbs diagrams,correlation analyses,ion ratio coefficients,and factor analysis were used to demonstrate the formation mechanism of the hydrochemical composition of the groundwater.Groundwater ion characteristics were found to be influenced by rock weathering and evaporation,with rock weathering being the most significant factor.It was also clarified that Ca2+-Mg2+,Na+-Cl-,Na+SO42-,SO42--Cl-and F--B3+in the groundwater had the same ion sources mainly from the dissolution and leaching of rock and soil minerals.It was found that Na+ in sodium-containing rock minerals and Ca2+ and Mg2+ in the underground were alternately adsorbed by cations,which resulted in the enrichment of Na+in groundwater.The first principal component variables TDS,Na+,B3+,HCO3-and Fare the dominant factors controlling the chemical characteristics of the groundwater.3.Water quality,pollution status,and health risk assessments were conducted separately for the centralized underground water drinking source in Fuyang.The single-factor evaluation showed that the water quality indicators were SO42-,Cl-,Fe2+,Mn2+,Na+,F-,B3+ and TDS,and 85.7%of the water source met class Ⅳ and Ⅴgroundwater standards.The evaluation of the pollution status of groundwater showed that pollution-free and lightly polluted groundwater sources accounted for 97.62%.The results of the health risk assessment showed that the total non-carcinogenic risk index of children with Fe2+,Mn2+,F-,and B3+in groundwater was greater than that of adults,and the total non-carcinogenic risk index of F-was greater than 1,which may threaten the health of adults and children through drinking water.4.By conducting the indoor fluoride removal experiments,CeCl3-modified chlorella biochar was used as the adsorbent,with a maximum fluoride adsorption capacity of 228.73 mg/g.The adsorption mechanism of fluoride by Ce-CB was demonstrated to be ion exchange and complexation.Meanwhile,the adsorption isotherm and kinetics were wellsimulated with Sips model and pseudo-second order model,respectively.The fluoride removal device for the stable recycling of activated alumina was developed,with automaticconfiguration of the corresponding regeneration solution after using saturated activated alumina,which improves groundwater fluoride removal efficiency. |
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