典型岩溶地下水系统地球化学敏感性研究

Study on Geochemical Susceptivity of Groundwater System in Representative Karstic Regions

通过研究典型岩溶地下水系统地球化学敏感性表明,地下水系统水化学阳离子以Ca2+、Mg2+为主,平均敏感指数分别为0.73和0.19;阴离子以HCO3-和SO24-为主,平均敏感指数分别为0.92和0.37;主量元素表现出明显的地球化学敏感性特征.研究区主量元素的地球化学敏感性依次为:HCO3->Ca2+>SO42->Mg2+>Cl->Na+>NO3->K+.运用敏感性最强的HCO3-敏感性指数(GSIHCO3-)对地下水系统进行敏感区域区划,GSIHCO3-<0.5的区域为低敏感区,0.5<GSIHCO3-<1的区域为中度敏感区,GSIHCO3->1的区域为高敏感区.高敏感区域地下水系统可能成为污染物的汇和源,地下水与地表水之间的频繁快速转化和相互补给可能形成两者交叉污染和叠加污染的恶性循环.

We investigated geochemical susceptivity of groundwater in representative karst groundwater system. The results indicated that Ca^2 ＋ and Mg^2 ＋ ,correlative the average values of geochemical susceptivity index （GSI） were 0. 73 and 0. 19; HCO 3^- and SO4^2 -, interrelated the average values of geochemical susceptivity index were 0. 92 and 0. 37,are the principal cations and anions in karstic groundwater system,respectively. And the major elements are obviously characterized by the geochemical susceptivity. The rank order of geochemical susceptivity for major elements in study region is HCO 3^-〉 Ca^2 ＋ 〉SO4^2 -〉 Mg^2 ＋ 〉Cl - 〉Na^＋〉 NO ^3-〉 K ^＋ . The susceptive regions of groundwater system were zoned by the geochemical susceptivity index of HCO 3^- （GSIHCO 3^- ）,which classified as GSIHCO 3^- 0. 5 is low-susceptivity zone,0. 5 GSIHCO 3^- 1 is moderate-susceptivity zone and GSIHCO 3^- 1 is high-susceptivity zone, respectively. The groundwater systems in high-susceptivity zone may become as a collected and genetic room for pollutants. Furthermore,both continual or active exchange and mutual recharge between surface water and groundwater in high-susceptivity zones might induce intersectant pollution and serious cycle.