[Atmospheric deposition of polychlorinated naphthalenes in Dongjiang River basin of Guangdong Province].

Atmospheric deposition of polychlorinated naphthalenes (PCNs) was investigated at 11 sites in Dongjiang River basin of Guangdong Province during the winter (January and February) and summer (July and August) of 2010 to assess the effect of PCNs on those areas. The average daily deposition fluxes of total PCNs was 828 pg x (m2 x d)(-1), and the corresponding TEQ was 0.14 pg x (m2 x d)(-1). Based on these values, the presumed average annual deposition value of sigma PCNs was 8.5 kg for Dongjiang River basin within Guangdong province, while the corresponding TEQ was 1.3 g. Spatially, the average daily deposition fluxes of PCNs in Guangzhou and Dongguan were much higher than that in Huizhou, and the fluxes were higher in urban areas than those in rural areas. Seasonally, the fluxes were generally higher in summer than those in winter. Tri-CNs dominated the deposition fluxes in all samples and contributed to more than 50% of total PCNs. In addition, higher contents of high chlorinated PCNs (penta-CNs to octa-CN) were found in Guangzhou and Dongguan in comparison with Huizhou. Combustion and other sources may both contribute to the PCNs emission in the Dongjiang River basin. Combustion related source may be the main contributor of PCNs in Dongguan; while non-combustion related source may dominate the contribution to the site of Guangzhou.