ASSESSMENT OF SURFACE WATER QUALITY IN SOC TRANG PROVINCE FOR THE PERIOD 2014 - 2024 USING SEVERAL WQI CALCULATION METHODS

Abstract

This study assessed surface water quality in Soc Trang province from 2014 to 2024 using three indices: WQI-VN, WAWQI and RTWQI. Data from 17 monitoring sites included pH, DO, BOD₅, COD, TOC, N-NH₄⁺, N-NO₃^-, N-NO₂^-, P-PO₄^3-, coliform, total nitrogen and total phosphorus. Results indicate that most rivers and inland canals are polluted by organic matter, nutrients and microorganisms, with water quality generally rated as poor or fair, suitable mainly for navigation or irrigation; the Hau river (NM05) showed better quality. WQI-VN effectively captured temporal variations, RTWQI provided more stable assessments, while WAWQI was stricter when compared with QCVN 08:2023/BTNMT standards. These findings provide a scientific basis for managing, protecting and improving surface water quality for domestic, agricultural and aquaculture purposes.