近日，印度国家水文研究所Y. S. Prasad团队报道了印度南部三角洲海水入侵：来自水文地球化学和稳定同位素的证据。该项研究成果发表在2026年3月17日出版的《地球化学学报》杂志上。

印度的三角洲地区由于靠近海洋、河流径流量减少以及地下水的大量开采，极易遭受海水入侵。该研究在印度南部的佩纳尔河三角洲开展，旨在利用水文地球化学指标和稳定同位素（δ¹⁸O 和 δ²H）评估浅层和深层含水层的海水入侵情况。降雨变化成为影响地下水波动的主要因素。关键盐度指标（Na/Cl、Mg²⁺/Ca²⁺、Ca²⁺/(HCO₃^-+ SO₄^2-)）、Na-Cl 水化学类型、水化学相演化图（HFE-D）以及稳定同位素共同证实了多种盐化机制的存在。维达瓦卢鲁和穆图库鲁曼达尔（mandals，印度基层行政单位）的沿海地点显示出强烈的盐度特征，表现为升高的Cl^-/碱度比值和较低的总碱度（TA）/总硬度（TH）值。

克里希纳帕特南和卡特帕利附近的浅井显示出与水产养殖相关的直接海水入侵，并伴有蒸发海水导致的同位素富集。内陆三角洲的深井显示出极端的盐度，但其同位素组成具有大气降水来源特征，表明存在古盐度或深层高盐水锥进的影响。伊萨卡帕利靠近海岸的深井总溶解固体（TDS）相对较低，但 Mg²⁺/Ca²⁺比值升高且同位素值类似海水，表明其受到蒸发作用的早期盐化阶段影响，可能源自邻近的盐田。内拉图鲁的浅井水质反映了来自灰池的咸性地表水渗漏。因此，地下水的盐度升高来源于直接海水入侵、蒸发浓缩、古盐度以及人为污染。防止灰池渗漏并规范沿海地区的地下水开采，对于保护淡水资源免受海水入侵至关重要。

附：英文原文

Title: Seawater intrusion in a delta of southern India: Evidence from hydrogeochemistry and stable isotopes

Author: Prasad, Y. S., Ramana, R. V., Jeyakanthan, V. S., Rao, Y. R. S.

Issue&Volume: 2026-03-17

Abstract: Deltaic regions of India are highly vulnerable to seawater intrusion due to the proximity to the sea, reduced river discharge, and intensive groundwater extraction. This study was carried out in the Pennar delta of southern India to evaluate seawater intrusion in shallow and deep aquifers using hydrogeochemical indicators and stable isotopes (δ18O and δ2H). Rainfall variation emerged as the primary factor influencing groundwater fluctuations. Key salinity indicators (Na/Cl, Mg2+/Ca2+, Ca2+/HCO3+SO42), Na–Cl facies, hydrochemical facies evolution diagrams (HFE-D), and stable isotopes confirm multiple salinization mechanisms. Coastal sites in Vidavaluru and Muthukuru mandals show strong salinity, reflected by elevated Cl/alkalinity ratios and low total alkalinity (TA)/total hardness (TH) values. Shallow wells near Krishnapatnam and Katepalli indicate direct seawater intrusion linked to aquaculture, with isotopic enrichment from evaporated seawater. Deep wells of the inland delta show extreme salinity with a meteoric isotopic composition, suggesting paleo-salinity or upconing of highly saline water. Deep wells near the seacoast at Isakapalli have relatively low total dissolved solids (TDS) but elevated Mg2+/Ca2+ and seawater-like isotopic values, suggesting early-stage salinization influenced by evaporation, likely from adjacent saltpans. The shallow wells at Nelaturu reflect saline surface water seepage from an ash pond. Thus, groundwater salinity arises from direct seawater intrusion, evaporative enrichment, paleo-salinity, and anthropogenic contamination. Preventing leakage from ash ponds and regulating extraction in coastal zones are vital to protecting freshwater resources from seawater intrusion.

DOI: 10.1007/s11631-026-00863-5

Source: https://link.springer.com/article/10.1007/s11631-026-00863-5