1. Identification of sources and transformations of nitrate in Cr(VI)-impacted alluvial aquifers by a hydrogeochemical and δ15N-NO3− and δ18O-NO3– isotopes approach.
- Author
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Pyrgaki, Konstantina, Kelepertzis, Efstratios, Argyraki, Ariadne, Boeckx, Pascal, Botsou, Fotini, and Dassenakis, Emmanuel
- Subjects
GEOCHEMICAL modeling ,AQUIFERS ,MULTIVARIATE analysis ,NITROGEN isotopes ,HEXAVALENT chromium ,SEWAGE ,GROUNDWATER monitoring ,AQUIFER pollution - Abstract
A coupled methodology of nitrogen isotopes, hydrogeochemical characterization, multivariate statistical analysis, and SIAR Bayesian modeling has been employed to identify the sources of NO
3 − and N transformation processes in three alluvial aquifers (Schinos, Thiva, and Central Evia) located in central Greece where geogenic Cr(VI) co-occurs with agricultural activity and rural development. Hexavalent chromium concentrations exceed 50 μg/L in many sampling stations of the studied groundwater bodies, while nitrate contamination is evident in all three study areas with concentrations well over 50 mg/L. The mean δ15 N-NO3 – and δ18 Ο-NO3 − values are 6.67 ± 1.77‰ and 2.68 ± 1.77‰ in C. Evia, 8.72 ± 4.74‰ and 3.96 ± 4.57‰ in Schinos and 4.44 ± 1.71‰ and 2.91 ± 1.02‰ in Thiva, respectively. Domestic sewage and N-bearing fertilizers are contributing in various degrees to the observed nitrification which is the dominant transformation process of N in the studied aquifers. Multivariate statistics indicated that the main processes identified in the study areas are salinization, silicate dissolution, and groundwater contamination due to fertilizer use. It is suggested that ultramafic rock–related alluvial aquifers must be closely monitored in terms of nutrient inputs as an effective measure for controlling Cr(VI) release in groundwater. [ABSTRACT FROM AUTHOR]- Published
- 2022
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