Spatial and Temporal Trends in Surface Water Quality and Pollution Sources in Ben Tre, Vietnam: A Principal Component Analysis/Factor Analysis-based Approach

Authors

• Nguyen Xuan Tong
• Luu Tang Phuc Khang

Publication Date

2025

Abstract

Surface water quality is vital for maintaining ecological health and supporting sustainable development, particularly in the Mekong Delta, Vietnam, where water is heavily utilized. However, rapid urbanization and economic activities have led to water pollution. This study assessed the spatial and temporal variations in surface water quality in Ben Tre Province from January 2022 to December 2023 using 384 samples collected across dry and rainy seasons and two zones (headwater streams and cities). The water quality index (WQI) was calculated on the basis of 15 parameters, and principal component analysis/factor analysis was applied to identify pollution sources. Five key factors influencing water quality, explaining 66.95% of the total variance. These factors reflect the impacts of urbanization, agriculture, aquaculture, and natural conditions, with notable spatial differences in BOD₅, COD, nutrients, and suspended solids. Hierarchical agglomerative cluster analysis was applied to distinguish pollution vulnerability, In the dry season, two clusters emerged: headwater sites with good water quality and urban sites with elevated BOD₅, COD, nutrients, TSS, and coliforms. During the rainy season, three clusters were identified: a main group reflecting moderate runoff effects, a subset of sites with turbidity and nutrient spikes, and a single outlier (S35) with extreme iron and coliform levels under flood conditions. The WQI values revealed that water quality was better during the rainy season, with urban areas generally exhibiting higher WQIs than headwater streams. Correlation analysis highlighted the strong relationship between BOD₅ and COD (r = 0.99), while both were negatively correlated with WQI (r = -0.46 and r = -0.40, respectively). DO was positively correlated with WQI (r = 0.35) and inversely related to NH₄⁺-N (r = -0.34). Fe was strongly positively correlated with WQI (r = 0.77). The organic and nutrient pollution exceeds regulatory limits in some areas, highlighting the need for improved wastewater management.

DOI

10.35762/AER.2025019

First Page

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Last Page

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Recommended Citation

Xuan Tong, Nguyen and Phuc Khang, Luu Tang (2025) "Spatial and Temporal Trends in Surface Water Quality and Pollution Sources in Ben Tre, Vietnam: A Principal Component Analysis/Factor Analysis-based Approach," Applied Environmental Research: Vol. 47: No. 2, Article 9.
DOI: 10.35762/AER.2025019
Available at: https://digital.car.chula.ac.th/aer/vol47/iss2/9