Research On Hydrogeochemical Characteristics And Water Quality Assessment Of Groundwater In Heilonggang Basin Of Handan City

Heilonggang plain is an important agricultural production base in Hebei Province.Due to the lack of surface water in the area,groundwater has become the main water supply source supporting its agricultural development and domestic water supply.In recent years,with the rapid development of economy,groundwater has been seriously overdrawn and the water level has continuously reduced,which has changed the circulation mode of groundwater and caused significant changes in the process of hydrochemical evolution.In order to realize the harmonious and sustainable development of groundwater resources and human society,it is urgent to elucidate the hydrogeochemical characteristics and water quality status of groundwater in this region.?1?Groundwater,canal water and river water receive the recharge from atmospheric precipitation and are subjected to intense evaporation.In the vicinity of Laozhanghe River and Dongfengqu Canal,groundwater interacts with surface water closely.The?¹⁸O spatial distribution characteristics of groundwater indicate that the shallow groundwater?¹⁸O is enriched in Nanxindian,Xiangchenggu and Beixiaogu areas,while the deep groundwater?¹⁸O is enriched in Nanliyue and Chencun areas.?2?The spatial distribution characteristics of shallow groundwater TDS are generally low in southwest and high in northeast.The brackish water area is mainly distributed in the northeast of the study area,while the deep groundwater is basically fresh water.The chemical types of shallow groundwater are mainlyNa-Mg-HCO₃andNa-Mg-SO₄-HCO₃ andNa-Mg-SO₄-Cl types,while deep groundwater is mainlyNa-Mg-SO₄-Cl-HCO₃ andNa-HCO₃ types.Groundwater in the study area is mainly controlled by rock weathering,and the gypsum,halite dissolution is the main source of groundwater chemical components.In addition,Glauber's salt,dolomite and calcite also contribute to the chemical compositions in groundwater.By chlor-alkali index and ion correlation analysis,it is found that cation exchange and artificial input in water have significant effects on groundwater chemistry.?3?Results of drinking water quality assessment for groundwater in the study area,for the shallow groundwater?18 samples?,9 samples belonged to?class;for deep groundwater?21 samples?,5 groups fell into?class water.The overall water quality is bad,deep groundwater in Quzhou county,North-East Guantao county,Feixiang county is not suitable for drinking.The sodium?%Na?and residual sodium carbonate?RSC?in groundwater exceeded the standard seriously,which affected the overall irrigation water quality.The shallow groundwater is unsuitable for irrigation,but the deep groundwater is suitable for irrigation purpose.