Hydro-Geochemical Assessment of Groundwater Quality in Aseer Region, Saudi Arabia

Abstract

Saudi Arabia is an arid country with very limited water resources. The absence of surface water bodies along with erratic rainfall renders groundwater as the most reliable source of potable water in arid and semi-arid regions globally. Groundwater quality is determined by aquifer characteristics regional geology and it is extensively influenced by both natural and anthropogenic activities. In the recent past, several methodologies have been adopted to analyze the quality of groundwater and associated hydro-geochemical process i.e., multivariate statistical analysis, geochemical modelling, stable isotopes, a redox indicator, structural equation modelling. In the current study, statistical methods combined with geochemical modelling and conventional plots have been used to investigate groundwater and related geochemical processes in the Aseer region of Saudi Arabia. A total of 62 groundwater samples has been collected and analyzed in laboratory for major cations and anions. Groundwater in the study region is mostly alkaline with electrical conductivity ranging from 285–3796 μS/cm. The hydro-geochemical characteristics of groundwater are highly influenced by extreme evaporation. Climatic conditions combined with low rainfall and high temperature have resulted in a highly alkaline aquifer environment. Principal component analysis (PCA) yielded principal components explaining 79.9% of the variance in the dataset. PCA indicates ion exchange, soil mineralization, dissolution of carbonates and halite are the major processes governing the groundwater geochemistry. Groundwater in this region is oversaturated with calcite and dolomite while undersaturated with gypsum and halite which suggests dissolution of gypsum and halite as major process resulting into high chloride in groundwater. The study concludes that the combined approach of a multivariate statistical technique, conventional plots and geochemical modelling is effective in determining the factors controlling the groundwater quality.

Investigation of groundwater salinity using geophysical and geochemical approaches: heuningnes catchment coastal aquifer. Western Cape Province, South Africa

“…The groundwater samples which were tested indicate Mg 2+ /Ca 2+ ratios above 1 (Table 4) however, they fall below the seawater range implying that other sources are responsible for salinization of groundwater such as (reverse cation exchange, dolomite dissolution processes or sewage invasion). To define freshwater and seawater mixing SO 4 2− /Cl − ratio is used as a natural tracer, in seawater the value of (SO 4 2− /Cl − ) * 1000 is found to be 103.4 and, as established from these values the quality of groundwater can be classified into two clusters (i) samples with a SO 4 2− /Cl − ratio similar to seawater, and (ii) samples with a ratio of SO 4 2− /Cl − ratio more than 300, mainly influenced by dissolution of evaporates according to Mallick et al (2018). In the present study, the ratio of (SO 4 2− /Cl − ) * 1000 ranges from 0 to 100; none of the samples are above 300 indicating no influence of seawater on groundwater.…”

GIS-based spatio-temporal and geostatistical analysis of groundwater parameters of Lahore region Pakistan and their source characterization

“…Municipal or domestic sewage waste, fertilizers, and atmospheric precipitation are the primary sources of Clions in groundwater (Mallick et al 2018). Low percentages (up to 3 %) of the samples were found to have Clvalues exceeding the WHO recommended limits for drinking water, as given in Table 3.…”

Physical–chemical evaluation of groundwater quality in semi-arid areas: case study—Sabzevar plain, Iran

“…Hiscock et al (1995) assessed the groundwater vulnerability and showed that the GIS is appropriate for the information extraction and is flexible in revising the classification plan. Mallick et al (2018) assessed the quality of groundwater in the Aseer region of Saudi Arabia. Their research showed that geochemical modeling has an important role in identifying the effective factors of groundwater quality.…”