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In order to assess the pollution of polycyclic aromatic hydrocarbons(PAHs) in a suburban farmland soil, 29 sampling sites were collected around Nanjing according to the grid method, and the contents of 15 different PAHs were determined. Acenaphthene(Ace) was not detected in any of the samples. The total content of PAHs in farmland soil ranged from 24.49 to 750.04 μg·kg -1 , with an average of 226.64 μg·kg -1 . The spatial distribution of high-ring PAHs, the main PAHs in the farmland soil, was similar to that of total PAHs. There was no significant correlation between PAHs and soil organic matter(SOM), pH, cation exchange capacity(CEC), and total nitrogen(TN), whereas bulk density and low ring PAHs were significantly correlated. The results of source apportionment show that the main source of PAHs in the farmland soil is a mixture of combustion and petroleum. The contamination severity index(CSI) index shows that the PAHs does not pose an ecological risk. The results of the health risk assessment show that there is no potential carcinogenic risk to children or adults, and the main sequence of exposure is skin contact>ingestion>inhalation.

The construction of highway ecological landscape is an important part of highway entity and an iconic feature of scenic countryside and ecological garden city, which plays an important role in the process of achieving social and economic sustainable development. The efficient index system and method is a basic measurement for the assessment of the interior quality and its associated outer environment. By taking five arterial highways (G15, G228, G204, S334 and S335) in the territory of Nantong City, Jiangsu Province as the case, an evaluation system containing quantitative and qualitative indices was developed to deal with the ecological landscape quality. The system composed of 12 evaluation indices which were divided into three categories including ornamental value, ecological efficiency, and safety design. Based on the survey and calculation of the raw data, the variable matrix was established and analyzed with principal component (PC) analysis. The results showed that the equation of highway greening ecological evaluation score was H=0.694×PC1+0.191×PC2+0.115×PC3, and scores of 5 highways ranked in the ordination of G204 > G15 > S334 > G228 > S335. The results would provide methods and references for efficient evaluation of highway landscape.