|
|
Han, D., & Currell, M. J. (2018). Delineating multiple salinization processes in a coastal plain aquifer, northern China: hydrochemical and isotopic evidence. Hydrology and Earth System Sciences, 22(6), 3473–3491.
Abstract: Groundwater is an important water resource for agricultural irrigation and urban and industrial utilization in the coastal regions of northern China. In the past 5 decades, coastal groundwater salinization in the Yang–Dai river plain has become increasingly serious under the influence of anthropogenic activities and climatic change. It is pivotal for the scientific management of coastal water resources to accurately understand groundwater salinization processes and their causative factors. Hydrochemical (major ion and trace element) and stable isotopic (δ18O and δ2H) analysis of different water bodies (surface water, groundwater, geothermal water and seawater) were conducted to improve understanding of groundwater salinization processes in the plain's Quaternary aquifer. Saltwater intrusion due to intensive groundwater pumping is a major process, either by vertical infiltration along riverbeds which convey saline surface water inland, and/or direct subsurface lateral inflow. Trends in salinity with depth indicate that the former may be more important than previously assumed. The proportion of seawater in groundwater is estimated to have reached up to 13 % in shallow groundwater of a local well field. End-member mixing calculations also indicate that the geothermal water with high total dissolved solids (up to 10.6 g L−1) with depleted stable isotope compositions and elevated strontium concentrations (> 10 mg L−1) also mixes locally with water in the overlying Quaternary aquifers. This is particularly evident in samples with elevated Sr ∕ Cl ratios (> 0.005 mass ratio). Deterioration of groundwater quality by salinization is also clearly exacerbated by anthropogenic pollution. Nitrate contamination via intrusion of heavily polluted marine water is evident locally (e.g., in the Zaoyuan well field); however, more widespread nitrate contamination due to other local sources such as fertilizers and/or domestic wastewater is evident on the basis of NO3 ∕ Cl ratios. This study provides an example of how multiple geochemical indicators can delineate different salinization processes and guide future water management practices in a densely populated water-stressed coastal region.
|
|
|
|
Neal, C., Neal, M., Hughes, S., Wickham, H., Hill, L., & Harman, S. (2007). Bromine and bromide in rainfall, cloud, stream and groundwater in the Plynlimon area of mid-Wales. Hydrology and Earth System Sciences, 11(1), 301–312.
|
|
|
|
Mahindawansha, A., Külls, C., Kraft, P., & Breuer, L. (2020). Investigating unproductive water losses from irrigated agricultural crops in the humid tropics through analyses of stable isotopes of water. Hydrology and Earth System Sciences, 24(7), 3627–3642.
|
|
|
|
Hanshaw, B. B., & Back, W. (1985). Deciphering hydrological systems by means of geochemical processes. Hydrological Sciences Journal, 30(2), 257–271.
Abstract: The distribution of permeability and chemical character of groundwater in carbonate aquifers is significantly influenced by the many diagenetic processes
and reactions that occur in the early development of these rocks. Many of these diagenetic processes occur in the transition zone formed as the carbonate sediments emerge from the marine environment and become fresh-water aquifers. Analyses of trace elements and isotopes
indicate that calcite cements and dolomites are formed in this groundwater mixing zone. Reverse reactions such as mineral dissolution and dedolomitization occur in carbonate aquifer systems. The geochemical reactivity of the fresh-water/salt-water mixing zone results from the nonlinearity of geochemical parameters as a function of ionic strength and causes extensive dissolution in coastal carbonate rocks. Interpretation of geochemical reactions and isotopic composition of groundwater provides a method to determine hydrological parameters
such as porosity, hydraulic conductivity, and groundwater flow rates. This geochemical method is largely independent of the more conventional approach of determining these parameters by an evaluation of physical properties of aquifer systems.
|
|
|
|
Gat, J. R. (1980). The relationship between surface and subsurface waters: water quality aspects in areas of low precipitation / Rapport entre les eaux de surface et les eaux souterraines: aspects des propriétés caractéristiques de l’eau dans les zones à précipitation faible. Hydrological Sciences Bulletin, 25(3), 257–267.
Abstract: In the temperate and semiarid environment the salinity of both surface and subsurface(meteoric) waters is dominated by the weathering products of soil and aquifer minerals, since even surface waters have a history of subsurface flow. In the desert environment, in contrast, surface flows are more superficial and their chemistry dominated by the aeolian salinity. This has both a marine input and
a contribution from recycled salinity from surface accumulation of evaporitic minerals. Both these sources have chloride (and to a lesser extent sulphate) as the dominant anion.
|
|
