Dustfall-bound polycyclic aromatic hydrocarbons (PAHs) over the fifth largest Chinese lake: residual levels, source apportionment, and correlations with suspended particulate matter (SPM)-bound PAHs in water.

Residual levels and temporal-spatial distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) in dustfall were studied at the seasonal scale between June 2010 and May 2011 in the fifth largest shallow lake in China. PAHs flux of atmospheric deposition and the impact on the PAHs in the lake water column were estimated. The major sources of PAHs were identified by multiple methods. We found that (1) the seasonal residual levels of 16 priority controlled PAHs (PAH) were spring (8.89 ± 3.93 μg g) > summer (6.68 ± 4.31 μg g) > winter (6.06 ± 2.95 μg g) > autumn (3.55 ± 2.21 μg g). (2) Significant positive correlations were found between the PAH levels in the dustfall and the suspended particle material (SPM) content, as well as between the deposition flux and the PAH content in the water in all four seasons. (3) Vehicle emissions, coal combustion, biomass combustion, and coke ovens were the four major sources in Lake Chaohu, accounting for 12.7%, 40.9%, 14.5%, and 31.9% of the total PAHs, respectively. (4) Compared to long-distance trajectories, short-distance trajectories played a more important role in the external sources of atmospheric PAHs in the region of Lake Chaohu.