Abstract：
The Italian Apennines are among the most important sources of freshwater for several Italian regions. With evidences of deep CO2-rich fluids intruding into aquifers in the nearby central-southern Apennines, a thorough investigation into the geochemistry of groundwater became critical to ensure the water quality in the area. Here, we show the main hydrogeochemical processes occurring in the Matese Massif (MM) aquifer through the investigation of 98 water samples collected from springs and water wells. All waters were classified as HCO3 type with Ca dominance (from 50% up to 97%) and variable amount of Mg (from 1% up to 49%). A multivariate statistical approach through the application of the factor analysis (FA) highlighted three main hydrogeochemical processes: (i) water-carbonate rock interactions mostly enhanced in peripheral areas of the MM by CO2 deep degassing; (ii) addition of NaCl-rich components linked to recharging process and to water mixing processes of the groundwater with a thermal component relatively rich in Cl, Na, and CO2; (iii) anthropogenic activities influencing groundwater composition at the foothills of MM. Furthermore, the first detailed TDIC, pCO2, and δ13C-TDIC distribution maps of the MM area have been created, which track chemical and isotopic anomalies in several peripheral areas (Pratella, Ailano, and Telese) throughout the region. These maps systematically highlight that the greater the amount of dissolved carbon occurs the heavier the C isotope enrichment, especially in the peripheral areas. Conversely, spring waters emerging at higher altitudes within MM are only slightly mineralized and associated with δ13C-TDIC values mainly characterized by recharging processes with the addition of biogenic carbon during the infiltration process through the soil.
摘要：
意大利亚平宁山脉是意大利几个地区最重要的淡水来源之一。有证据表明，富含CO2的深层流体侵入附近中南部亚平宁山脉的含水层，对地下水地球化学的彻底调查对于确保该地区的水质至关重要。这里,通过调查从泉水和水井收集的98个水样，我们显示了Matese地块（MM）含水层中发生的主要水文地球化学过程。所有水域均被分类为HCO3型，Ca占主导地位（从50％到97％），Mg含量可变（从1％到49％）。通过应用因子分析（FA）的多元统计方法强调了三个主要的水文地球化学过程：（i）通过CO2深度脱气在MM的外围区域主要增强了水-碳酸盐岩的相互作用；（ii）添加与补给过程和地下水的水混合过程相关的富含NaCl的成分，Na,和CO2；（iii）影响MM山麓地下水组成的人为活动。此外，第一个详细的TDIC，已创建MM区域的pCO2和δ13C-TDIC分布图，跟踪几个外围区域的化学和同位素异常(Pratella，Ailano,和Telese）整个地区。这些地图系统地强调，溶解碳的数量越多，C同位素富集越重，尤其是在周边地区。相反，在MM中的高海拔地区出现的泉水仅略微矿化，并与δ13C-TDIC值相关，其特征主要是在通过土壤的渗透过程中添加了生物碳。
