Evaluation of groundwater quality in central Saudi Arabia using hydrogeochemical characteristics and pollution indices.

Talal Alharbi,Abdelbaset S El-Sorogy,Fahad Alshehri,Saleh Qaysi

doi:10.1007/s11356-021-14575-1

Abstract

The groundwater quality and heavy metal (HM) contamination were evaluated in palm farms, central Saudi Arabia, using pollution indices, irrigation quality parameters, and multivariate statistical analyses. Thirty groundwater samples were collected in October 2020 for major anions, cations, and HMs analyses and interpretation. The results showed that the average concentrations of total dissolved solids (TDS), Ca+, Na+, K+, Cl-, SO42-, and F- were greater than the permissible limits of the WHO standards for drinking water. The groundwater facies types were Ca-Na-SO4-Cl (23 samples), Ca-Cl-SO4, (4 samples), and Ca-SO4-Cl type (3 samples). The groundwater quality index indicated that 15 groundwater samples were of good quality and 15 were of poor quality, whereas the metal index and heavy metal pollution index indicated that all samples were categorized as slightly affected and with low pollution, respectively. The variation is attributed to the increasing average concentrations of some ions and decreasing HMs. The dissolution/precipitation of silicates, gypsum, and carbonates and soil leaching were the natural factors affecting groundwater chemistry, whereas higher PO43-, NO3-, F-, Pb, and Zn values in some samples may be attributed to human activities from the extensive use of fertilizers and pesticides on the investigated farms.

Highlights

Groundwater is a critical resource for domestic and agricultural needs, especially in arid countries, where the geochemical processes resulting from aquifer–water interaction often control its quality in such minimal rainfall recharge (Alharbi 2018)
The results showed that the average values of TDS, Ca +, Na +, K +, Cl −, SO 4 2−, and F − were greater than the permissible limits of the WHO standards for drinking water
As groundwater is an important source of heavy metals (HMs) for these plants and can reach humans directly or indirectly, this study evaluates the groundwater quality and HM contamination in some palm farms in central Saudi Arabia in the Al Uyaynah-Al Jubailah region and documents the possible sources of contamination, using hydrogeochemical characteristics, pollution indices, and multivariate analyses

Summary

Introduction

Groundwater is a critical resource for domestic and agricultural needs, especially in arid countries, where the geochemical processes resulting from aquifer–water interaction often control its quality in such minimal rainfall recharge (Alharbi 2018). The thick Mesozoic and Cenozoic sedimentary rocks function as a prolific aquifer for groundwater in central Saudi Arabia (Alharbi and Zaidi 2018). Overdependence on groundwater resources, especially in arid countries, often leads to decreased groundwater levels and deteriorates its quality (Alharbi 2018). The rapid population growth in and extension of agricultural activities around Saudi Arabia have increased the need for freshwater resources (Khanfar 2008; Al-Hammad and Abd El-Salam 2016). The Al Uyaynah-Al Jubailah region (Fig. 1) is located 40–55 km northwest of Riyadh, inside the narrow, dry riverbed of Wadi Hanifa, which continues southwards through Dir'iyyah and Riyadh

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Results

Conclusion