Water Chemistry Characteristics And Conservation Conditions Study Of Beijing-Tianjin-Hebei Water Conservation Area

The characteristics of water environment and quality are the main controlling factors of water conservation,holding a great significant impact on the rational use of regional water resources and ecologically sustainable development.To promote the overall utilization and protection of water resources in Chengde and its downstream,in this paper,Xinglong county,an important source of water resources in the south of Chengde,is selected as a typical research area.79 water test results of field samples collected in 2019,were adopted to the statistical analysis,GIS spatial analysis,hydrogeochemical graphic,and water quality evaluation method to comprehensively understand the spatial distribution characteristics of water chemistry,the provenance basis of major components,and the formation conditions and water conservation conditions.The research result indicates that:?1?The distribution of various water chemistry types in the study area is consistent with the distribution of stratigraphic lithology,especially controlled by the continuous exposure of carbonate rocks in the area,the water chemistry types are mainly HCO₃-Ca·Mg type?62%?,and the hydrochemical type dominated by HCO₃^-accounted for 89.8%.?2?In each watershed,cations are mainly Ca²⁺and Mg²⁺,and anions are mainly HCO₃^-;TDS is related to Na⁺,Mg²⁺,K⁺,Ca²⁺,Cl^-,SO₄^2-and EC,and Cl^-is related to Na⁺,K⁺and Ca²⁺,and Ca²⁺is related to Mg²⁺,and K⁺is related to Na⁺,and Sr is related to K⁺and Na⁺;water clustering is related to lithology.?3?The groundwater is generally in an oxidizing environment with good connectivity to the atmosphere,and its water chemical components are mainly derived from the water-rock interaction.During the leaching process of atmospheric precipitation,the formation mechanism of the main components is related to the dissolution,filtration and leaching of carbonate rocks,aluminosilicate,and sulfate minerals,and the alternating adsorption of cations,and the direction is that Ca²⁺and Mg²⁺in groundwater exchange Na⁺and K⁺in the surrounding rock;The SI of feldspar,gypsum,anhydrite,calcite,dolomite and other minerals in the area are all less than 0,unsaturated,and continue to dissolve.?4?Beneficial elements such as Sr and Se are enriched in the distribution area of metamorphic rocks and intrusive rocks,and the strontium content has a pH effect,the strontium content is significant between 7.8-8.4.The enrichment of strontium content is controlled by water-rock interaction and structure,alternate cation adsorption and the chemical properties of Ca²⁺and Mg²⁺promote the release of strontium,and the typical strontium-rich pattern in the study area is water storage structure-intrusive vein blockage type.?5?The whole study area is weakly alkaline water with low TDS.The main ion components are rarely exceeded,only SO₄^2-?3 groups?and NO₃^-?2 groups?have exceeded the limit,and Se,As and Sb exceeded in many water samples;Except for the water samples near the mining area that are of Class IV and V,the remaining are mostly Class I and II,accounting for 93.59%of the total,and the water quality is good.In summary,the conservation area is low-mineralized water,riching in Sr and Se healthy elements,and most water quality grades are Class I and II.It has good water conservation conditions,supporting the development of Chengde Ecological Civilization,and ensuring the safety of drinking water in Beijing,Tianjin and Hebei.