The Content And Distribution Of Polycyclic Aromatic Hydrocarbons(PAHs)of Urban Forest Soil In Nanjing

Polycyclic aromatic hydrocarbons(PAHs), which is hydrophobic organic pollutants widespread in the environment, by two or more benzene ring as condensed form connected, PAHs can cause cancer, birth defects and respectively. This paper use ribbon sampling method,takes different use ways of city forestry soil in Nanjing,by analyzing the content, distribution and source of PAHs in the soil to get know the distribution and pollution status of PAHs in urban forestry soil in nanjing, And by analyzing the correlation between soil physical and chemical properties and the content of PAHs to get know factors of PAHs distribution in soil; To explore the adsorption behavior of PAHs in urban forest soil, and explore the influence factors of soil adsorption soil. The main results were as follows:(1) It has a big difference of PAHs content in different land use soils, range from 221.53ug/kg to 1134.90, the average of PAHs in surface soil in nanjing is 504.19 ug/kg,it has most PAHs in urban overpass and road green belt soil, secondly is residential areas, schools, and power plant, least is landfill, close suburbs forests and far suburbs forest; Between different levels of PAHs content in soil, surface is higher than the middle higher than the lower. By analyzing showed that the sources of PAHs in road greening, urban overpasses, power plants, school is the combustion source, landfill, residential areas, close suburbs forests and far suburbs forest is the oil pollution source.(2) It has significantly positive correlation between organic carbon and black carbon in urban forestry soils of nanjing, Pearson correlation coefficient is 0.876; It has significantly positive correlation between organic carbon, black carbon and PAHs in urban forestry soils of nanjing, Pearson correlation coefficient is 0.611 and 0.789, black carbon effect on the distribution of PAHs in soil is greater than the influence of organic carbon. Pearson correlation coefficient of PAHs and rapidly-available potassium is 0.319, they have significantly positively related; Pearson correlation coefficient of PAHs and total nitrogen is 0.673, they have significantly positive correlation. Pearson correlation coefficient of PAHs and Percentage of soil clay is 0.654, has very significantly positive correlation.(3) Linear fitting model and Freundlich model can be used for adsorption phenanthrene in urban forestry soil in nanjin, the adsorption strength rule of phenanthrene in different land use is: urban overpass > road green belt > far suburbs forest > close suburbs forests, adsorption strength between different soil layers is surface > below middle > lower.Add moisture content and pH can reduced adsorption ability of phenanthrene in soil, It has significantly positive correlation between organic carbon,black carbon and adsorption coefficient Kd, Pearson correlation coefficient is 0.837 and 0.875. It has significant positive correlation between the percentage of clay soil and adsorption coefficient Kd, Pearson correlation coefficient is 0.827.