Polycyclic aromatic hydrocarbons sources identification based on multiple indices from the Yangtze estuarine and nearby coastal areas

Samples of suspended particulate matters (SPMs), surface sediment and road dusts were collected in the Yangtze estuarine and nearby coastal areas, coastal rivers, and Shanghai metropolitan area, respectively. Sixteen polycyclic aromatic hydrocarbons (PAHs) in the USEPA priority-controlled list were determined by GC-MS and compound-specific stable carbon isotopes of individual PAHs were analyzed by GC-C-IRMS. PAHs sources of SPMs and surface sediments in the Yangtze estuarine and nearby coastal areas were examined using multiple source identification techniques which integrated molecular mass indices with organic compound-specific stable isotopes. The results showed that the third and fourth rings PAH compounds were dominant in SPMs and surface sediments, similar to those in Wusong sewage discharge outlet, Shidongkou sewage disposal plant, Huangpu River, coastal rivers and Shanghai metropolitan area. Principal component analysis (PCA) integrated with molecular mass indices indicated that gasoline, diesel oil, coal and wood combustion and petroleum were the main sources for PAHs in the Yangtze Estuary. Use of PAH compound-specific stable isotopes tracked PAHs input pathways. PAHs derived from wood and coal combustion and petroleum were input into the Yangtze estuarine and nearby coastal areas by coastal rivers, sewage discharge outlets in dry season and urban storm water runoff in flood season. PAHs derived from vehicle emissions were mainly accumulated in road dusts from urban traffic lines and commercial district, which entered the coastal area by the northwest prevailing wind in dry season and storm water runoff in flood season.