[Distribution and partition of polycyclic aromatic hydrocarbons in surface water from the Pearl River estuary]

To obtain the temporal and spatial distribution and partition of PAH between water and particles in coastal area, water samples were collected from the Pearl River Estuary in July 2002 (summer) and April 2003 (spring) and polycyclic aromatic hydrocarbons (PAHs) were analysed with GC-MS in the present study. Total PAH concentrations in water samples were higher in spring (c(p): 4.0-39.1 ng/L; c(w): 15.9-184.2 ng/L) than in summer (c(p): 2.6-26.6 ng/L; c(w): 13.0-28.3 ng/L). Suspended particle matter (SPM) content, photogradation and riverine discharge were the major factors controlling the PAH concentrations in water. The 3-ring PAHs were the dominant PAHs in water samples. The 5 and 6 ring PAHs are more enriched in the inner estuary samples than in outside estuary samples, and the 3 ring PAHs are more enriched in summer samples than in spring samples. The differences in composition and source of SPM might be responsible for this observation. The partition coefficient (Kp) increased with the particular organic carbon content of SPM and salinity of water and decreased with the SPM content of samples, which were consistent with the PAH partition theory. A linear correlation between IgK(OC) and lgK(OW) were found in two sampling periods. The observed values of lgK(OC) exceed their predicted values calculated form linear free energy relationship between lgK(OC) and lgK(OW).