[Over one hundred year sedimentary record of polycyclic aromatic hydrocarbons in the Pearl River Estuary, South China].

The western shoal of the Lingding Bay is known to be an important deposition zone of terrestrial substance in the Pearl River Estuary (PRE). In this study, the vertical variations of concentration and fluxes of polycyclic aromatic hydrocarbon (PAH) are investigated in a core from the west shoal of Lingding Bay. In combining with 210Pb-dating, the PAHs sedimentary record in the last 100 years is reconstructed. The sigmaPAH concentration ranged from 59 ng x g(-1) to 330 ng x g(-1) throughout the core with two distinct peaks. An initial increase in sigmaPAH concentration was found around the 1860s, followed with the first maximum in the 1950s. There was a decrease in total PAHs concentration and flux in 1960s and 1970s. A sharp increase in PAHs levels was observed from 1980s and a maximum was found in the 1990s. PAHs diagnostic ratios indicate that PAH in the sediment core are mainly of pyrolytic origin. PAHs concentrations are found to correlate positively with the Gross Domestic Production, vehicle numbers and power generation in the surrounding regions, indicating that the PAHs in the sediment core are mainly anthropogenic. Atmospheric deposition and land runoff may serve as the important pathway of PAHs input to the sediment.