穆兴平原北区浅层地下水水化学分布特征及其形成机理

Hydrochemical distribution characteristics of shallow groundwater in the north of Muling-Xingkai Plain and their formation mechanism

采用2016年8月采集的192个地下水样品水化学数据,查明了穆棱河—兴凯湖平原(穆兴平原)北区第四系浅层地下水溶解性总固体(TDS)和地下水化学类型分布特征,并结合研究区水文地质条件和人类活动影响分析其形成原因。结果表明:穆兴平原北区浅层地下水主要以TDS小于0.5g/L的淡水为主,未见TDS大于1.0g/L的微咸水。地下水TDS受含水介质、溶滤作用和地表水-地下水交互作用影响,在区内呈多种分带规律。区内浅层地下水化学类型不具备明显的水平分带规律,主要以HCO_3-Ca·Mg型水为主,与人为活动较少的20世纪60年代背景水化学类型(HCO_3-Ca·Na型水)对照,地下水中硫酸根、氯离子及镁离子的增加与煤矿开采、生活用水污染及大范围农业施肥等人类活动相关。

We studied the distribution characteristics of total dissolved solids （ TDS ） and hydrochemical types of shallow groundwater in the Muling-Xingkai Plain on the basis of analyzing 192 groundwater samples.Then we explored the cause of formation by considering the hydrogeological conditions and human activities.The results showed that the shallow groundwater in the study area was mainly fresh water with TDS less than 0.5 g/L,and there was no saline groundwater with TDS higher than 1.0 g/L.Influenced by aquifer medium,leaching,and groundwater-river interaction,the groundwater TDS showed zonal distribution in the study area.There was no obvious zonal distribution regularity of the hydrochemical types in the study area.Nowadays,the HCO 3-Ca·Mg type water has replaced the HCO 3-Ca·Na type water in the 1960 s （considered as background water type） to become the common water type in the study area.The increases of sulfate ion,chloride ion,and magnesium ion in groundwater were mainly due to coal mining,domestic wastewater pollution,and fertilization.