|
|
Panagopoulos, G. (2009). Application of major and trace elements as well as boron isotopes for tracing hydrochemical processes: the case of Trifilia coastal karst aquifer, Greece. Environmental Geology, 58(5), 1067–1082.
|
|
|
|
Stigter, T. Y., van Ooijen, S. P. J., Post, V. E. A., Appelo, C. A. J., & Carvalho Dill, A. M. M. (1998). A hydrogeological and hydrochemical explanation of the groundwater composition under irrigated land in a Mediterranean environment, Algarve, Portugal. Journal of Hydrology, 208(3), 262–279.
Abstract: In the Campina de Faro, in the south of Portugal, agricultural practices have a large impact on groundwater composition. These practices involve pumping of water for irrigation from combinations of large diameter, shallow wells (noras) and small diameter, deep boreholes (furos). Excess irrigation water returns to the aquifer and mixes with water from the regional groundwater flow system. This irrigation return flow is concentrated by strong evapotranspiration and by flushing of fertilisers. The concentration increase induces cation exchange, whereby Ca on the soil exchanger is replaced by Na. The mixing in the aquifer allows application of a mixing cell model which may then be used to calculate transmissivities from the Cl mass balance. The calculations are complicated by the time-variant behaviour of Cl and the method is adjusted to calculate the change of chloride in time. Results from the calculations appear to be in good agreement with hydrochemical observations.
|
|
|
|
Wigley, T. M. L., & Plummer, L. N. (1976). Mixing of carbonate waters. Geochimica et Cosmochimica Acta, 40(9), 989–995.
Abstract: When mineral solutions of different compositions are mixed, the molalities and activities of individual ions in the mixture are often non-linear functions of their end-member values. This non-linearity is particularly significant in determining mineral saturation levels. Mixtures of saturated solutions may be either undersaturated or supersaturated depending on the end-member compositions and the physical conditions in which end-members and their mixtures exist. In carbonate solutions important non-linear effects occur due to redistribution of carbonate species. In extreme cases this causes mixture pH to be below both the end-member pH values. A simple but precise computer program (WATMIX) has been developed for calculating mixture composition for closed and open system mixing of arbitrary end-members. A number of mixing examples are considered which allow one to isolate three important processes leading to non-linear behaviour: the algebraic effect, the δPCO2 effect, and the ionic strength effect.
|
|
|
|
Zhou, X., & Li, C. (1992). Hydrogeochemistry of deep formation brines in the central Sichuan Basin, China. Journal of Hydrology, 138(1), 1–15.
Abstract: Subsurface brines are abundant in the Sichuan Basin, China. Five brine-bearing aquifers have been identified within rocks of Triassic age in the central part of the basin. These are of two types: brine-bearing clastic and brine-bearing carbonate aquifers. Brines in this region have high total dissolved solids and chemical species that are different from those of evaporatively concentrated seawater. Deep formation brines in clastic aquifers, in which evaporites do not exist, are characterized by high concentrations of Ca, Sr, Ba, Br and I, low concentrations of Mg and K, and lack of SO4, and are dominated by the NaCaCl type. Brines in carbonate aquifers, which have interbeds of evaporites, are characterized by high total dissolved solids, low concentrations of Ca, Mg and SO4, and lack of Ba, and are of the NaCl type. The brines in clastic aquifers originate from connate continental sedimentary waters mixed with marine waters; membrane filtration through shales has played an important part in modifying the chemical compositions and increasing the salinity of the brines. Those in carbonate aquifers are bittern marine sedimentary waters, with chemical compositions mainly controlled by precipitation of evaporites.
|
|
|
|
Kurunc, A., Ersahin, S., Sonmez, N. K., Kaman, H., Uz, I., Uz, B. Y., et al. (2016). Seasonal changes of spatial variation of some groundwater quality variables in a large irrigated coastal Mediterranean region of Turkey. Science of the Total Environment, 554, 53–63.
Abstract: Soil and groundwater degradations have taken considerable attention, recently. We studied spatial and temporal variations of groundwater table depth and contours, and groundwater pH, electrical conductivity (EC), and nitrate (NO3) content in a large irrigated area in Western Mediterranean region of Turkey. These variables were
monitored during 2009 and 2010 in previously constructed 220 monitoring wells. We analyzed the data by geostatistical techniques and GIS. Spatial variation of groundwater table depth (GTD) and groundwater table contours (GTC) remained similar across the four sampling campaigns. The values for groundwater NO3 content, EC, and pH values ranged from 0.01 to 454.1 g L−1 , 0.06 to 46.0 dS m−1 and 6.53–9.91, respectively. Greatest
geostatistical range (16,964 m) occurred for GTC and minimum (960 m) for groundwater EC. Groundwater NO3 concentrations varied both spatially and temporally. Temporal changes in spatial pattern of NO3 indicated that land use and farming practices influenced spatial and temporal variation of groundwater NO3. Several hot spots occurred for groundwater NO3 content and EC. These localities should be monitored more frequently and
land management practices should be adjusted to avoid soil and groundwater degradation. The results may have important implications for areas with similar soil, land use, and climate conditions across the Mediterranean region.
|
|
