Polycyclic aromatic hydrocarbons in the water-SPM-sediment system from the middle reaches of Huai River, China: Distribution, partitioning, origin tracing and ecological risk assessment

- The PAHs levels in surface and bottom layer are higher than those in up-middle and bottom-middle layer in the water column.
- A model describing the PAHs transformation in water-SPM-sediment system was established.
- The high ecological risk of PAHs indicates the remedial actions must be conducted at once.

The polycyclic aromatic hydrocarbons (PAHs) concentrations in the water, suspended particulate matter (SPM) and sediment from the middle reaches of Huai River were analyzed by a gas chromatograph-mass spectrometer (GC-MS). The mean concentrations for the sum of 16 PAHs (∑16 PAHs) in the water, SPM and sediment were 1204 ng/L, 3192 ng/g (dry weight; dw), and 7955 ng/g (dw), respectively. Along the vertical profiles of water columns, higher ∑16 PAHs levels were seen in surface and bottom water layers and co-located SPM. The PAHs distribution in water and SPM is found to be controlled by organic carbon. Based on the statistic correlations of the organic carbon normalized partition coefficients (lgKOC) and octanol-water partition coefficient (lgKOW), we observed that the calculated partition coefficients do not increase as large as that would be expected from the increase of hydrophobicity. The principal component analysis suggests that coal combustion and the petroleum refinery were the primary PAHs contributors in the studied water-SPM-sediment system. The high ecological risks of PAHs in studied system highlight the urgent needs for remedial actions.

260