SIMAU - Department of Materials, Environmental Sciences and Urban Planning, Polytechnic University of Marche, Via Brecce Bianche 12 60131 Ancona, Italy.
DiSTABiF - Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Campania University "Luigi Vanvitelli", Via Vivaldi 43 81100, Caserta, Italy.
Water Res. 2024 Oct 1;263:122145. doi: 10.1016/j.watres.2024.122145. Epub 2024 Aug 2.
To counteract the ongoing salinization of coastal aquifers, which poses a significant environmental and socioeconomic challenge to local communities, it is necessary to first understand the origin and mechanisms of this phenomenon. This study investigates the origins of salinity in the Volturno River lowland in Southern Italy and reveals that the primary source in the area is paleo-seawater entrapped within sediments that were subject to evapoconcentration processes. By systematically collecting sediment samples at variable depths and locations and extracting porewaters, a comprehensive understanding of the interplay between freshwater and saline water was gained, including complex patterns of vertical stratification of groundwater salinity. The study highlights the limitations of traditional methods that rely on salinity monitoring via integral depth sampling, particularly in capturing the vertical redox and salinity gradients characteristics of layered aquifer/aquitard systems. On the contrary, environmental tracers, like chloride and bromide, provide valuable insights into the sources of groundwater salinity, distinguishing between current seawater intrusion and other causes, such as paleo-seawater and return flow from drained agricultural land. Results suggest that the majority of salinity does not originate from modern seawater intrusion or recent evaporation. Instead, it can be attributed to paleo-seawater affected by evapoconcentration processes. This study has broader implications for the sustainable management of coastal aquifers and the safeguarding of freshwater resources. While our findings are specific to the Volturno River coastal area, the methodologies and insights here presented can be reproduced in every coastal region facing similar salinity challenges.
为了应对沿海含水层的持续盐化，这对当地社区构成了重大的环境和社会经济挑战，首先需要了解这种现象的起源和机制。本研究调查了意大利南部沃尔图诺河低地盐分的来源，并揭示了该地区的主要盐分来源是被蒸发浓缩过程困在沉积物中的古海水。通过系统地在不同深度和位置采集沉积物样本并提取孔隙水，全面了解了淡水和咸水之间的相互作用，包括地下水盐分垂直分层的复杂模式。该研究强调了传统方法的局限性，这些方法依赖于通过整体深度采样进行盐度监测，特别是在捕捉分层含水层/隔水层系统的垂直氧化还原和盐度梯度特征方面。相比之下，环境示踪剂，如氯和溴，为地下水盐度的来源提供了有价值的见解，能够区分当前海水入侵和其他原因，如古海水和从排水农业用地回流的水。研究结果表明，大部分盐分并非来自现代海水入侵或最近的蒸发。相反，它可以归因于受蒸发浓缩过程影响的古海水。本研究对沿海含水层的可持续管理和保护淡水资源具有更广泛的意义。虽然我们的研究结果是针对沃尔图诺河沿海地区的，但这里提出的方法和见解可以在每个面临类似盐分挑战的沿海地区复制。
