泰安城区孔隙水水化学特征及水质评价

Hydrochemical characteristics and water quality evaluation of pore water in urban district of Tai'an

为分析泰安市城区孔隙水水化学特征及水质现状,选取2021年采集的31件水样,运用数理统计、Piper三线图、Gibbs图、离子比值等方法分析孔隙水主要离子特征及控制因素,运用改进的内梅罗综合指数评价法对孔隙水水质进行评价。结果表明:泰安城区孔隙水阳离子以Ca^(2+)、Na^(+)为主,阴离子以HCO_(3)^(-)、SO_(4)^(2-)为主;pH值6.75~8.10,整体呈弱碱性;TH含量211~1226 mg·L^(-1),平均603 mg·L^(-1),属于硬水—极硬水;TDS含量368~2002 mg·L^(-1),平均917 mg·L^(-1),属于淡水—微咸水;NO_(3)^(-)含量3.08~111.07 mg·L^(-1),平均31.85 mg·L^(-1);K+、NO_(3)^(-)、Cl-和SO_(4)^(2-)的空间差异性较强。孔隙水水化学类型复杂,水化学成分主要受岩石风化作用的控制,以碳酸盐岩的风化溶解为主,其次为硅酸盐岩风化溶解,同时还受阳离子交替吸附作用和人类活动的影响。研究区孔隙水水质相对较差,Ⅳ、Ⅴ类水占样品总数的74.19%,水质影响因子主要为NO_(3)^(-)和总硬度。

In order to analyze the hydrochemical characteristics and quality status of pore water in the urban district of Tai'an,31 water samples collected in 2021 were selected to analyze the main ion characteristics and control factors of pore water by using mathematical statistics,Piper three line diagram,Gibbs diagram,ion ratio and other methods.The improved Nemero comprehensive index evaluation method was used to evaluate the quality of pore water.The results show that the cation of pore water in Tai'an urban area is mainly Ca^(2+)and Na^(+),while the anion is mainly HCO_(3)^(-)and SO_(4)^(2-).The pH value ranges from 6.75 to 8.10,showing an overall weak alkaline.The TH content ranges from 211 to 1226 mg·L^(-1),with an average of 603 mg·L^(-1),belonging to the category of hard water to extremely hard water.The TDS content ranges from 368 to 2002 mg·L^(-1),with an average of 917 mg·L^(-1),belonging to the category of freshwater to brackish water.The content of NO_(3)^(-)ranges from 3.08 to 111.07 mg·L^(-1),with an average of 31.85 mg·L^(-1).The spatial differences of K+,NO_(3)^(-),Cl-,and SO_(4)^(2-)are strong.The hydrochemical types of pore water are complex,and the hydrochemical composition is mainly controlled by weathering of rocks,mainly the weathering and dissolution of carbonate rock,followed by the weathering and dissolution of silicate rock.At the same time,it is also affected by the alternative adsorption of cations and human activities.The pore water quality in the study area is relatively poor,with classⅣandⅤwater accounting for 74.19%of the total sample size.The main factors affecting water quality are NO_(3)^(-)and total hardness.