Seventy-five polycyclic aromatic compounds (PACs) were detected in sediments, river water (dissolved phase and suspended particulate matter, SPM), and riparian soils along the coal-impacted Huai River, China. Mean ΣPAC concentrations were 77 ± 43 ng/L in the dissolved phase, 200 ± 150 ng/L in SPM, 4000 ± 13,000 ng/g in sediments, and 5100 ± 12,000 ng/g in riparian soils. Priority PAHs (PriPAHs) dominated across compartments, while alkylated naphthalenes and perylene were also notable. Toxicity assessment showed that 5–6 ring PACs dominated ΣPAC toxicity, implying that ΣPriPAHs alone may underestimate total toxicity by excluding alkylated 5–6 ring PACs and nonpriority PAHs. Spatial patterns and compositional fingerprints suggested that coal-related activities increased PAC concentrations without clearly altering relative profiles. Diagnostic ratios, alkyl-to-parent relationships, and fugacity analysis indicated that sediments are a key secondary source, releasing PACs through fugacity-driven diffusive exchange and resuspension, while resuspended SPM may further sustain dissolved PACs via desorption. Source apportionment suggested combustion dominance in soils, sediments, and SPM, whereas dissolved PACs also reflected noncombustion inputs, such as fossil-fuel leakage. Based on river discharge, the annual downstream flux of PACs was estimated at ∼7.8 t.
Wu et al. (Wed,) studied this question.