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

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.