Spatial distribution of perfluoroalkyl acids in the Pearl River of southern China.

An intensive campaign was conducted in September 2012 to collect surface water samples along the tributaries of the Pearl River in southern China. Thirteen perfluoroalkyl acids (PFAAs), including perfluorocarboxylates (PFCAs, C4-C11) and perfluorosulfonates (PFSAs, C4, C6-C8, and C10), were determined using high-performance liquid chromatography/negative electrospray ionization-tandem mass spectrometry (HPLC/(-)ESI-MS/MS). The concentrations of total PFAAs (ΣPFAAs) ranged from 3.0 to 52 ng L(-1), with an average of 19±12 ng L(-1). The highest concentrations of ΣPFAAs were detected in the surface water of the Dong Jiang tributary (17-52 ng L(-1)), followed by the main stream (13-26 ng L(-1)) and the Sha Wan stream (3.0-4.5 ng L(-1)). Perfluorooctanoate (PFOA), perfluorobutane sulfonate (PFBS), and perfluorooctane sulfonate (PFOS) were the three most abundant PFAAs and on average accounted for 20%, 24%, and 19% of ΣPFAAs, respectively. PFBS was the most abundant PFAA in the Dong Jiang tributary, and PFOA was the highest PFAA in the samples from the main stream of the Pearl River. A correlation was found between PFBS and PFOA, which suggests that both of these PFAAs originate from common source(s) in the region. Nevertheless, the slope of PFBS/PFOA was different in the different tributaries sampled, which indicates a spatial difference in the source profiles of the PFAAs.