The synergistic role of agricultural activities in groundwater quality in ultramafic environments: the case of the Psachna basin, central Euboea, Greece

Papazotos, Panagiotis; Vasileiou, Eleni; Perraki, Maria

doi:10.1007/s10661-019-7430-3

Cited by 48 publications

(16 citation statements)

References 109 publications

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“…Moreover, most of the samples representing a high Na and Cl, also represent a high concentration of Ca, Mg, HCO 3 , Cl and SO 4 reflecting ion exchange process. Thus, it can be inferred that reverse ion exchange is also a key process responsible for the hydrochemical variation in the study area during NEM and SWM [85]. However, ion exchange process is more dominant in SWM compared with NEM.…”

Section: Ionic Ratiosmentioning

confidence: 89%

Geochemical variations due to salinization in groundwater along the southeast coast of India

et al. 2021

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In recent years, the extraction of groundwater (GW) in coastal aquifers has rendered the fragile aquifers more saline due to the sea water intrusion. Groundwater from the coastal aquifers of the Pudhucherry region were sampled to study the process of salinization. An integrated approach was adopted to identify the salinization process, by coordinating the results of borehole geophysics, rainfall pattern, water level variation, hydrochemical characters and multivariate statistical analysis. A total of 136 groundwater samples were collected during two different seasons, southwest monsoon (SWM) and northeast monsoon (NEM). The major cations and anions were analyzed adopting standard procedures. Resistivity and litholog indicate that the southeastern (SE) part of the study region has lower resistivity than in north. Based on electrical conductivity (EC) and total dissolved solids (TDS) values, most of the samples are potable, except for few samples from southeastern region. The study results indicated that higher values of Na, EC, K, SO4, Mg and Cl were observed during NEM, indicating leaching of salt into the aquifer and ion exchange process. The predominant hydrochemical facies of groundwater was Na-Cl and Ca–Mg–Cl type reflecting the saline water and the mixing process of saltwater and fresh groundwater, respectively. Though more number of samples with higher EC was noted in NEM, the results of PCA and correlation analysis indicate the predominance of leaching of salts and intense agricultural activities. The process of sea water intrusion was observed to be dominant during SWM.

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Section: Ionic Ratiosmentioning

confidence: 89%

Geochemical variations due to salinization in groundwater along the southeast coast of India

et al. 2021

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“…The phenomenon of seawater intrusion has been recorded in many coastal areas, such as in Texas, Florida, Indonesia, Syria, in South Asia (Bangkok) in Africa (Nigeria, Egypt and Tunisia), China, Australia, and Europe (Cyprus, Turkey, Estonia, Italy, and Greece) [10,12,23,25,[31][32][33][34][35][36][37][38]. Global review publications provide an extensive array of field, laboratory, and computer-based techniques for the investigation of the seawater intrusion, its composition, and prediction of freshwater-saltwater interfaces over regional scales [23,[41][42][43][44][45][46].…”

Section: Global Distribution Of Coastal Groundwatermentioning

confidence: 99%

The Cr(VI) Stability in Contaminated Coastal Groundwater: Salinity as a Driving Force

Eliopoulos

Economou-Eliopoulos

2021

Minerals

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Chromium concentrations in seawater are less than 0.5 μg/L, but the Cr(VI) in contaminated coastal groundwater affected by Cr-bearing rocks/ores and/or human activities, coupled with the intrusion of seawater may reach values of hundreds of μg/L. A potential explanation for the stability of the harmful Cr(VI) in contaminated coastal aquifers is still unexplored. The present study is an overview of new and literature data on the composition of coastal groundwater and seawater, aiming to provide potential relationships between Cr(VI) with major components in seawater and explain the elevated Cr(VI) concentrations. It is known that the oxidation of Cr(III) to Cr(VI) and the subsequent back-reduction of Cr(VI) processes, during the transport of the mobilized Cr(VI) in various aquifers, facilitate the natural attenuation process of Cr(VI). Moreover, the presented positive trend between B and Cr(VI) and negative trend between δ53Cr values and B concentration may suggest that seawater components significantly inhibit the Cr(VI) reduction into Cr(III), and provide insights on the role of the borate, [B(OH)4]− ions, a potential buffer, on the stability of Cr(VI) in coastal groundwater. Therefore, efforts are needed toward the prevention and/or minimization of the contamination by Cr(VI) of in coastal aquifers, which are influenced by the intrusion of seawater and are threatened by changes in sea level, due to climate change. The knowledge of the contamination sources, hotspots and monitoring of water salinization processes (geochemical mapping) for every coastal country may contribute to the optimization of agricultural management strategies.

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“…The third class comprised the rest of natural springs, characterized by mixed water types and a Ca/Mg ratio above the 1:1 line, indicating a limited influence of serpentinites. The bivariate plot of Ca 2+ + Mg 2+ vs. HCO 3 − (Figure 13b) suggests an excess of (Ca 2+ + Mg 2+ ) over HCO 3 reflecting an additional non-carbonate source of Ca 2+ and Mg 2+ ions, such as the dissolution of silicate minerals [38,57]. Iron-Mg-silicates of ultramafic rocks, such as olivine, pyroxene, and amphibole are transformed to serpentine group minerals during the serpentinisation process.…”

Section: Hydrogeochemical Characterization Of the Natural Springs Of Western Vermio Mt The Ultramafic Fingerprintmentioning

confidence: 99%

“…reflecting an additional non-carbonate source of Ca 2+ and Mg 2+ ions, such as the dissolution of silicate minerals [38,57]. Iron-Mg-silicates of ultramafic rocks, such as olivine, pyroxene, and amphibole are transformed to serpentine group minerals during the serpentinisation process.…”

Section: Hydrogeochemistry Of Cr In Natural Ultramafic Springsmentioning

confidence: 99%

“…However, the geochemically immobile Cr(III) is oxidized into the mobile and toxic for the living organisms hexavalent chromium [Cr(VI)] in the presence of natural manganese oxides (MnO 2 ), specifically pyrolusite (b-MnO 2 ), in the typical range of groundwater pH (6.5-8.5) and under oxidizing redox potential (Eh) conditions [23][24][25][26][27][28]. Although an increasing number of studies focus on the occurrence and fate of Cr in the environment [29][30][31][32][33][34][35][36][37][38] only a few have systematically examined the geochemical fingerprint of water-ultramafic rock interaction in natural springs [29,33,35,39]. Typical worldwide examples of ultramafic springs with elevated groundwater concentrations of Cr(VI) have been recorded in the Province of La Spezia, Italy (up to 73 µg/L) [29], the Pollino massif, Italy (up to 30 µg/L) [40], the Gerania springs, Greece (up to 17.2 µg/L) [33], the Euboea Island, Greece (up to 37 µg/L) [41], and the Lesvos and Rhodes Islands, Greece (10-15 µg/L) [42].…”

Section: Introductionmentioning

confidence: 99%

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Hydrogeochemical Processes and Natural Background Levels of Chromium in an Ultramafic Environment. The Case Study of Vermio Mountain, Western Macedonia, Greece

Vasileiou

Papazotos

Dimitrakopoulos³

et al. 2021

Water

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The hydrogeochemical processes and natural background levels (NBLs) of chromium in the ultramafic environment of Vermio Mountain, Western Macedonia, Greece, were studied. Seventy groundwater samples were collected from 15 natural springs between 2014‒2020, and an extensive set of physical and chemical parameters were determined. The ultramafic-dominated environment of western Vermio Mt. favors elevated groundwater concentrations of dissolved magnesium (Mg2+), silicon (Si), nickel (Ni), and Cr in natural spring waters. Chromium was the principal environmental parameter that exhibited a wide range of concentrations, from 0.5 to 131.5 μg/L, systematically exceeding the permissible limit of 50 μg/L for drinking water. Statistical evaluation of hydrogeological, hydrochemical, and hydrological data highlighted the water-ultramafic rock process as the predominant contributor of Cr in groundwater. The NBL assessment for Cr and Cr(VI) was successfully applied to the typical ultramafic-dominated spring “Potistis” that satisfied all the methodology criteria. The NBLs of Cr and Cr(VI) were defined at 130 μg/L and 100 μg/L, respectively, revealing that a natural ultramafic-dominated environment exhibits the geochemical potential to contribute very high concentrations of geogenic Cr to groundwater. The holistic methodology, proposed herein, could be implemented in any catchment scale to assess geogenic and anthropogenic Cr-sources that degrade groundwater quality.

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The synergistic role of agricultural activities in groundwater quality in ultramafic environments: the case of the Psachna basin, central Euboea, Greece

Cited by 48 publications

References 109 publications

Geochemical variations due to salinization in groundwater along the southeast coast of India

Geochemical variations due to salinization in groundwater along the southeast coast of India

The Cr(VI) Stability in Contaminated Coastal Groundwater: Salinity as a Driving Force

Hydrogeochemical Processes and Natural Background Levels of Chromium in an Ultramafic Environment. The Case Study of Vermio Mountain, Western Macedonia, Greece

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