Monsoonal rainfall initiates autochthonous alteration of dissolved organic matter composition in Indian groundwaters

IF 3.1 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry Pub Date : 2025-02-01 DOI:10.1016/j.apgeochem.2025.106298

George J.L. Wilson , David A. Aind , Abhijit Mukherjee , David A. Polya , Daren C. Gooddy , Laura A. Richards

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引用次数: 0

Abstract

Groundwater contamination is a considerable threat to public health in many regions of the world. Strong seasonal variation in monsoon-affected regions can have significant effects on groundwater quality, yet these variations are not fully understood. Using excitation-emission matrix (EEM) fluorescent spectroscopy, we explore the seasonal dynamics of dissolved organic matter (DOM) composition along a transect in West Bengal, India. Groundwater, river water and ponds were sampled (n = 59) on a weekly/fortnightly basis, from the onset of monsoon to late-July, to gain an understanding of DOM temporal dynamics in aquifers at a critical point in seasonal hydrological conditions. Several fluorescent DOM (fDOM) components and indices were used to infer the source and nature of DOM. Although dissolved organic carbon (DOC) remained consistent throughout the sample timeframe, precipitation-associated spikes in fluorescence index (FI), specific ultraviolet absorbance (SUVA₂₅₄) and redox potential (Eh) likely point towards rainfall-induced increase of autochthonous DOM and the increase of microbial metabolic activity in response to oxygenated recharge. We suggest that observed fluctuations in organics were associated with concomitant changes in redox- and solubility-controlled elements (e.g. Fe and Mg), thus having wider implications on groundwater geochemistry and particularly the mobility of redox- and organic-sensitive solutes.

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来源期刊

Applied Geochemistry 地学-地球化学与地球物理

CiteScore

6.10

自引率

8.80%

发文量

272

审稿时长

65 days

期刊介绍： Applied Geochemistry is an international journal devoted to publication of original research papers, rapid research communications and selected review papers in geochemistry and urban geochemistry which have some practical application to an aspect of human endeavour, such as the preservation of the environment, health, waste disposal and the search for resources. Papers on applications of inorganic, organic and isotope geochemistry and geochemical processes are therefore welcome provided they meet the main criterion. Spatial and temporal monitoring case studies are only of interest to our international readership if they present new ideas of broad application. Topics covered include: (1) Environmental geochemistry (including natural and anthropogenic aspects, and protection and remediation strategies); (2) Hydrogeochemistry (surface and groundwater); (3) Medical (urban) geochemistry; (4) The search for energy resources (in particular unconventional oil and gas or emerging metal resources); (5) Energy exploitation (in particular geothermal energy and CCS); (6) Upgrading of energy and mineral resources where there is a direct geochemical application; and (7) Waste disposal, including nuclear waste disposal.