Use of factor analysis to identify sources controlling groundwater chemistry in the shallow coastal plain aquifer, Western Saudi Arabia

Abstract EN

R-mode Factor analysis was used to interpret collected data concerning the groundwater chemistry from the shallow coastal plain aquifer and relating them to specific factors that brought about changes in the water quality.

Five factors, accounting for nearly 81% of the total variance, were identified.

These factors reflect different chemical processes that control the groundwater chemistry.

Factor 1 reflects the most important process; namely the intensive evaporation which resulted in the highly mineralized water.

Other processes that could be associated with this factor include the chemical weathering of silicate minerals, ion exchange reactions and mixing processes.

Factor 2 represents the precipitation and dissolution of carbonate minerals (calcite and dolomite).

Factors 1 and 2 could be considered the major factors controlling the chemical composition of the groundwater since they account for 50 % of the total variance and together, they produce a chemical population ranging from low to extremely high saline water, which is confirmed by the chemical analysis results.

The other three factors, which dominate the chemical processes, include oxidation of pyrite, groundwater pollution and solubility of silica.

They could, therefore, be considered as contributor factors to the groundwater chemistry in an overall scale.

Distribution score maps of the first four factors were constructed to delineate their relative spatial impact.