Assessment of Groundwater Quality in Water-Scarce Areas of Tay Ninh Province Using Water Quality Indices

Abstract

Water quality indices are widely used around the world and in Vietnam to assess the quality of water for domestic use and industrial use. In this paper, we apply the Groundwater Quality Index (GWQI), the Composite Pollution Index (CPI), and the Heavy Metal Pollution Index (HPI) to assess groundwater quality in the Early Pliocene aquifer (n21) in water-scarce communes in Tay Ninh province for domestic use (including parameters: pH, TDS, hardness, Cl⁻, SO₄²⁻, NO₃⁻, NO₂⁻, NH₄⁺, Fe, As, Pb, Mn, and coliform). The results of a study on 49 groundwater samples, conducted from October 26, 2022, to November 20, 2022, indicate that groundwater quality according to the GWQI is classified into two categories: medium (accounting for 6.1% of the total samples) and good (93.9%); according to the CPI, groundwater quality is classified as clean (6.1%) and very clean (93.9%); according to the HPI, the results show that 100% of the samples are not contaminated by heavy metals. In most boreholes, the groundwater is good quality for domestic use; however, some sampling locations have TDS and coliform levels exceeding the standards and therefore require treatment before use. The study also demonstrates that water quality indices can provide a relatively reliable indicator of groundwater quality, thereby supporting improved planning, management, and exploitation of water resources and contributing to sustainable water resource development.