Distribution of polycyclic aromatic hydrocarbons in surface water and sediment near a drinking water reservoir in Northeastern China

The levels of polycyclic aromatic hydrocarbons (PAHs) in the water and the sediment samples collected near the Mopanshan Reservoir—the most important drinking water resource of Harbin City in Northeast China—were examined. A total of 16 PAHs were concurrently identified and quantified in the three water bodies tested (Lalin River, Mangniu River, and Mopanshan Reservoir) and in the Mopanshan drinking water treatment plant during the high- and low water periods. The total PAH concentrations in the water and sediment samples ranged from 122.7 to 639.8 ng/L and from 89.1 to 749.0 ng/g dry weight, respectively. Similar spatial and temporal trends were also found for both samples. The lowest Σ₁₆PAH concentration of the Mopanshan Reservoir was obtained during the high water period; by contrast, the Lalin River had the highest concentration during the low water period. The PAH profiles resembling the three water bodies, with high percentages of low-molecular weight PAHs and dominated by two- to three-ring PAHs (78.4 to 89.0 %). Two of the molecular indices used reflected the possible PAH sources, indicating the main input from coal combustion, especially during the low water period. The conventional drinking water treatment operations resulted in a 20.7 to 67.0 % decrease in the different-ringed PAHs in the Mopanshan-treated drinking water. These findings indicate that human activities negatively affect the drinking water resource. Without the obvious removal of the PAHs in the waterworks, drinking water poses certain potential health risks to people.