Ecological Risk Assessment and Source Contributions of Heavy Metals in the Sediment of the Chan Thnal Reservoir, Kampong Speu, Cambodia

Abstract

Metal contamination from farming, inadequate wastewater treatment, and poor disposal of municipal garbage are major threats to public health. This research aimed to (1) assess the extent of heavy metal contamination in sediment samples, (2) describe the distribution of heavy metals by locating likely pollution sources using a positive matrix factorization (PMF) model, and (3) quantify the potential ecological consequences associated with these metals at six different places around the Chan Thnal Reservoir. The findings indicated steady degradation and suggested moderate to high metal contamination. Fe > Zn > Cr > Cu > Pb > Co > As > Mn > Cd was the trend of metal concentrations in the sediment. Various soil pollution indices showed that most of the studied sediment samples were clean, moderately clean, or slightly contaminated. However, Co and Cd reached high-risk conditions posing a severe problem to the local population living in and around the Chan Thnal Reservoir. Principal component analysis (PCA) was used to estimate primary factors in PMF analysis. It was found that the contamination of As, Cu, Zn, Cd, and Pb originated from agricultural and traffic vehicle sources; however, Zn, Fe, Mn, Cr, and Cu were derived from natural sources (e.g., atmospheric deposition and compost amendment). Furthermore, Fe, Cd, Mn, Co, Pb, and Cr were generated from urban and industrial sources (metal coatings, plastic burning, wastewater irrigation, and sewage sludge). Accordingly, this research improves our knowledge of the prevalence of heavy metal pollution in agroecosystems, which may be used to foresee and mitigate the risks of heavy metal exposure to humans and other organisms.