Geochemical and isotopic study to determine sources and processes affecting nitrate and sulphate in groundwater influenced by intensive human activity - carbonate aquifer Gliwice (southern Poland). (January 2017)

• Record Type: Journal Article
• Authors: Jakóbczyk-Karpierz, Sabina; Sitek, Sławomir; Jakobsen, Rasmus; Kowalczyk, Andrzej
• Is Part Of: Applied geochemistry. Volume 76(2017:Jan.)
• Page Start: 168
• Page End: 181
• Publication Date: 2017-01
• Subjects: Environmental tracers -- Stable isotopes -- Nitrate -- Sulphate -- Geochemical modelling -- Carbonate aquifer -- Urban geochemistry; Environmental geochemistry -- Periodicals; Water chemistry -- Periodicals; Geochemistry -- Social aspects -- Periodicals; Geochemistry -- Periodicals; 551.9
• DOI: 10.1016/j.apgeochem.2016.12.005
• Languages: English
• ISSNs: 0883-2927

Abstract

Abstract: A multi-species, multi-stable-isotope approach (δ 15 NNO3, δ 18 ONO3, δ 34 SSO4, δ 18 OSO4, δ 18 OH2O and δ 2 HH2O ) was used together with environmental tracers (Ar, Ne, CFC-11 and CFC-12) and geochemical modelling to characterize sources and processes controlling concentrations of NO3 − and SO4 2- in groundwater of the carbonate aquifer Gliwice (southern Poland). The study area represents a strongly transformed environment with a range of human activities i.a. Agriculture, urbanization and industry. The δ 15 NNO3 and δ 18 ONO3 indicated that most samples contained NO3 − of mixed sources: artificial fertilizers, municipal and industrial sewage, while very good correlation between NO3 − and CFC-12 suggested that nitrate originated primarily from residential and industrial sewage. Conversely, isotopic composition of sulphate in groundwater suggested agriculture as well as oxidation of sulphides as dominant. The conclusion was supported by the comparison of CFCs and sulphate concentrations which revealed no relevant correlation. Geochemical modelling confirmed the presence of sulphate reduction in areas where isotopic analyses were not possible due to undetectable sulphate. Thus, the integrated application of stable isotopes, environmental tracers, groundwater chemistry and geochemical modelling shows a complex origin of groundwater pollution in the study area as well as variety of geochemical processes controlling chemistry of groundwater in a triple-porosity aquifer influenced by different types of human activity. Highlights: CFCs helped to identify municipal and industrial sources of NO3 − in groundwater. δ 18 O and δ 34 S suggested domination of SO4 2- from agriculture and sulphide oxidation. Sulphate reduction was confirmed using geochemical modelling for SO4 2- -free water.