[Distribution and sources of PAHs in soil from Liaohe estuarine wetland].

16 polycyclic aromatic hydrocarbons (PAHs) were measured by GC-FID for 31 surface soil samples collected from Liaohe estuary wetland in October of 2008 and May and August of 2009. The results showed that the total concentrations of PAHs in surface soil ranged from 293.4 ng x g(-1) to 1936.9 ng x g(-1) with a mean of 851.5 ng x ng(-1). The contents of PAHs were the highest in the oilwell reed field and the lowest in the beach. The total concentrations of PAHs and proportion of median and high molecular weight of samples collected in October was higher than those collected in May and August. The relative abundance of different benzene rings and the ratio analysis illustrated that pyrolysis was the main source in October, and the mixed pollution of pyrogenic and oil spill was the dominant source in May and August. The principle component analysis-multiple linear regression analysis (PCA-MLR) indicated that the major source in October was coal/vehicular emission (accounted for 45.5%), and the mixture of vehicular exhaust and oil spill was the major source in May and August (accounted for 75.2% and 42.2% respectively).

Probabilistic ecological risk assessment and source apportionment of polycyclic aromatic hydrocarbons in surface sediments from Yellow Sea.

Based on the concentrations of polycyclic aromatic hydrocarbons (PAHs) in 12 surface sediment samples from Yellow sea, the relative risk of 9 PAHs was investigated using joint risk probability distribution curves and overlapping area, which were generated based on the distributions of exposure and acute toxicity data (LC(50)), and the sources of PAHs were apportioned using principal component analysis. It was found that joint probability curve and overlapping area indicated the acceptable ecological risk of individual PAHs, only a small fraction of the benthic organisms was affected. Among the nine PAHs studied, the overall risk of pyrene was the highest, with that of naphthalene the lowest. For lower exposure levels at which the percentage of species affected was less than 10%, the risk associated with phenanthrene and fluorene were clearly higher than that of the other seven PAHs. It was indicated that PAHs in surface sediments mainly originated from vehicular emissions, coal combustion sources, coke oven emission and wood combustion, petroleum origin made little influence on sources of PAHs by PCA.