巴伊盆地平原区地下水水化学特征及污染源识别

Hydrochemical Characteristics and Pollution Source Identification of Groundwater in Plain Area of Barkol-Yiwu Basin

为探明新疆巴伊盆地平原区地下水水化学特征及形成机制并解析污染源,综合运用数理统计、图解法和PCA-APCS-MLR模型等方法,对2022年8月采集的4组泉水样、20组潜水样和11组承压水样的测试结果进行分析.结果表明,研究区地下水化学类型复杂多样,泉水以HCO_(3)·SO_(4)-Na·Ca型地下水为主,潜水以HCO_(3)·SO_(4)-Na·Ca型和HCO_(3)·SO_(4)-Ca型地下水为主,承压水水化学类型主要为HCO_(3)·SO_(4)-Na·Ca型和HCO_(3)·Cl·SO_(4)-Na·Ca型;未利用地承压水水化学类型单一(Cl·SO_(4)-Na·Ca型),耕地及城乡居民用地承压水水化学类型复杂,表明地下水受到人类活动影响;地下水演化过程主要受到水岩相互作用与阳离子交换作用的影响,从泉水至潜水至承压水阳离子交换作用逐渐增强,石膏及硬石膏的风化溶解作用逐渐减弱、岩盐的风化溶解作用逐渐加强;溶滤-富集作用(主要为蒸发岩的溶解)、人类活动因素(工业污染、农业污染、生活污染)和原生地质环境是影响研究区地下水的主要因素.

Groundwater is an important water supply source for production and life in arid and semi-arid areas.This study revealed the hydrochemical characteristics of groundwater in the Barkol-Yiwu Basin of Xinjiang and analyzed the pollution sources,which is of great significance in the sustainable utilization of local groundwater.Four spring water samples,20 unconfined groundwater samples,and 11 confined groundwater samples collected in August 2022 were analyzed using mathematical statistics,a graphic method,and the PCA-APCS-MLR model.The results showed that the chemical types of groundwater in the study area were complex and diverse.The spring water was mainly HCO_(3)·SO_(4)-Na·Ca type groundwater,the chemical types of unconfined groundwater were mainly HCO_(3)·SO_(4)-Na·Ca and HCO_(3)·SO_(4)-Ca,and the chemical types of confined groundwater were HCO_(3)·SO_(4)-Na·Ca and HCO_(3)·Cl·SO_(4)-Na·Ca.The hydrochemical type of confined water in unused land was single(Cl·SO_(4)-Na·Ca),and the hydrochemical types of confined groundwater in cultivated land and urban and rural residential land were complex,indicating that groundwater was affected by human activities.The evolution process of groundwater was mainly affected by water-rock interactions and cationic exchange.The cation exchange from spring water to unconfined groundwater to confined groundwater was gradually enhanced,the weathering and dissolution of gypsum and anhydrite was gradually weakened,and the weathering and dissolution of rock salt was gradually strengthened.Leaching-enrichment(mainly the dissolution of evaporite),human activities(industrial,agricultural,and domestic pollution),and the primary geological environment were the main factors affecting groundwater in the study area.