Assessment of groundwater quality based on principal component analysis and pollution source-based examination: a case study in Ho Chi Minh City, Vietnam.

The current study aimed to assess the quality of apportion pollution sources and examine the impacts of anthropogenic activities on groundwater. The study was implemented in two sequential steps of (1) bulk examination of groundwater quality followed by principal component analysis/factor analysis (PCA/FA) to apportion pollution sources and (2) pollution source-based examination to assess the effects of anthropogenic activities. Well-water samples were taken in Ho Chi Minh City, Vietnam, in 2015 (233 samples) and 2019 (20 samples) and analyzed for 8 and 15 water quality parameters, respectively. The results showed that 99% of studied wells had pH value lower than the permissible limit, and 29, 20, 15, and 14% of studied wells had concentrations of Fe, NH4+, COD (chemical oxygen demand), and coliform, respectively, higher than the maximum permissible limit. PCA/FA revealed that three pollution sources, ranked in the order of importance: agricultural, urban, and industrial activities, could mainly contribute to enriching the pollutant concentrations of groundwater. While agricultural activities may contaminate groundwater with organic substances, the urban area may enrich bacterial-pathogen density such as E. coli and coliform, and the industrial area may contribute to contaminating groundwater with some inorganic parameters. Groundwater quality index and ANOVA showed that groundwater of the studied area was poor to very poor in quality and that in the agricultural area was the worst of the three land-use types. In brief, the groundwater quality in the studied area was degraded and agricultural activities were the most important factor causing the degradation followed by urban and industrial activities.