Iran's Groundwater Hydrochemistry

Intrinsic biodegradation, representing the key process in Natural Attenuation, was examined at a tar-oil polluted disposal site. Methods to assess microbial natural attenuation of BTEX and PAH included analysis of groundwater hydrochemistry, pollutant profiles, composition of the microflora, and microcosm studies. In the polluted groundwater downgradient the disposal site, oxygen and nitrate were only available adjacent to the groundwater table and at the plume fringes. In the anaerobic core of the plume, a sequence of predominating redox zones (methanogenic, sulphate-reducing, Fe(III)-reducing) was observed. Changing pollutant profiles in the plume indicated active biodegradation processes, e.g. biodegradation of toluene and naphthalene in the anaerobic zones. High numbers of microorganisms capable of growing under anaerobic conditions and of aerobic pollutant degrading organisms confirmed the impact of biodegradation at this site. In microcosm studies, the autochthonous microflora utilised toluene, ethylbenzene, and naphthalene under sulfate- and Fe(III)-reducing conditions. Additionally, benzene and phenanthrene were degraded in the presence of Fe(III). Under aerobic conditions, all BTEX and PAH were rapidly degraded. The microcosm studies in particular were suitable to examine the role of specific electron acceptors, and represented an important component of the multiple line of evidence concept to assess natural attenuation.

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Surface and Groundwater Hydrochemistry of the Menengai Caldera Geothermal Field and Surrounding Nakuru County, Kenya

Energies ◽

10.3390/en12163131 ◽

2019 ◽

Vol 12 (16) ◽

pp. 3131 ◽

Cited By ~ 2

Author(s):

Nelly Montcoudiol ◽

Neil M. Burnside ◽

Domokos Györe ◽

Nicholas Mariita ◽

Thecla Mutia ◽

...

Keyword(s):

Ionic Composition ◽

Sampling Period ◽

Geothermal Field ◽

Wet Season ◽

Lake Nakuru ◽

Rock Interaction ◽

Geothermal Wells ◽

Groundwater Hydrochemistry ◽

Hydrological System ◽

Oxygen Isotopic

In order to assess the sustainability and impact of production from geothermal reservoirs on hydrological systems, a thorough understanding of local and regional hydrogeological systematics is a prerequisite. The Menengai Caldera in the Kenya Great Rift Valley is one of the largest explored geothermal fields in the country. This paper presents a hydrochemical investigation of the Menengai Caldera geothermal field and the ground and surface waters of the surrounding Nakuru County. Our results demonstrated a similar, sodium-alkaline dominated, ionic composition across all water types. Geothermal wells return the highest cation/anion concentrations and largely demonstrate a meteoric source from their δ18O and δ2H signature. Wells MW-09 (central part of the caldera), MW-18 (eastern part) and MW-20 (central part) showed a more evaporitic signature, closely matching with our own calculated Lake Evaporation Line, suggesting an increased mixing influence of Lake Nakuru waters. MW-09 also showed evidence of high-temperature oxygen isotopic exchange and significant water-rock interaction. Lake samples largely demonstrated seasonal shifts in ionic and isotopic values. Lake Nakuru ionic composition and isotopic values increased throughout the 12-month wet–dry–wet season sampling period. This correlated with a decrease in area which suggests a lessening of water inflow and facilitates increased evaporation. Groundwaters demonstrated clear evidence of mixing between meteoric, irrigation and lake waters. These observations enhanced the understanding of the hydrological system surrounding the Menengai Caldera and, when combined with future studies, will provide a powerful tool to assess the sustainability and impact of soon-to-be completed geothermal power production operations.

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Source identification of inrush water based on groundwater hydrochemistry and statistical analysis

Water Practice & Technology ◽

10.2166/wpt.2016.049 ◽

2016 ◽

Vol 11 (2) ◽

pp. 448-458 ◽

Cited By ~ 7

Author(s):

Linhua Sun ◽

Song Chen ◽

Herong Gui

Keyword(s):

Coal Mine ◽

Environmental Protection Agency ◽

Source Identification ◽

Water Source ◽

Rock Interaction ◽

Aquifer System ◽

Ion Concentrations ◽

Major Ion ◽

Aquifer Systems ◽

Groundwater Hydrochemistry

Water source identification is important for water hazard controlling in coal mines. In this study, major ion concentrations of the groundwater collected from four representative aquifer systems in the Baishan coal mine, northern Anhui Province, China, have been analysed by a series of statistical methods. The results indicate that the major ion concentrations of the groundwater from different aquifer system are different with each other, and provided the possibility of water source identification based on hydrochemistry. Factor analysis indicates that these differences are controlled by different types of water rock interactions. The analysis based on US Environmental Protection Agency (EPA) Unmix model identified three sources (weathering of silicate minerals, dissolution of carbonate and evaporate minerals) responsible for the hydrochemical variations of the groundwater. Also, it shows that their contributions for the groundwater in different aquifer systems vary considerably. Based on these variations and on step by step analysis, the source aquifer system for the groundwater samples with unknown source has been determined and, similar to the result obtained by the cluster and discriminant analysis. Therefore, EPA Unmix model can be applied for water source identification in coal mine, as it can provide information about water rock interaction and water source identification simultaneously.

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