Emerging contaminant pollution and source contributions in a mixed-land-use lake in Lam Dong, Vietnam: An integrated multivariate, receptor modeling, and ecological risk assessment

Developing tourist destinations in Southeast Asia harbor complex pollution sources due to the coexistence of agricultural, urban, and recreational activities. This study investigated water samples from Xuan Huong Lake in Da Lat, Vietnam, where 345 target compounds were quantified using wide-scope LC-HRMS following multi-layer solid-phase extraction. Among these targets, 184 compounds were detected at least once, and 97 occurred in more than 50% of samples [47 pharmaceuticals and personal care products (PPCPs), 38 pesticides, and 12 other substances], while 34 showed mean concentrations above 100 ng/L. Source identification was performed by comparing principal component analysis–multiple linear regression (PCA–MLR) and positive matrix factorization (PMF). Both methods successfully distinguished steady high-concentration pollutant sources, with PCA–MLR identifying four major pollutant groups dominated by PPCPs (R 2 : 0.8902). In contrast, the PMF model also resolved four source factors, with improved capability to separate sources linked to temporally and spatially variable pollutants (including one factor partly associated with runoff, contributing 16.0%). Furthermore, ecological risk assessment was conducted using the risk quotient (RQ) approach with predicted no-effect concentrations compiled from the NORMAN ecotoxicology database. It revealed that five neonicotinoid insecticides exhibited the highest risk potential as priority substances of concern, followed by amoxicillin (RQ: 2.08E+01) and hexa(methoxymethyl)melamine (2.53E+01). The findings of this study provide a scientific basis for integrated monitoring and management strategies to address emerging contaminants in mixed land-use watersheds. • Target analysis revealed diverse emerging contaminants in a Vietnamese lake • Caffeine, tributyl citrate, and acetaminophen showed high concentrations • PCA–MLR and PMF performances were compared for source contributions • PMF revealed season-specific contaminant patterns in the studied area • Emerging contaminants in the Vietnamese tourism region indicated potential risks