Urban soil anthropogenic activities

Because anthropogenic activities are the main sources of PAHs, the levels of PAHs in soils in urban areas are approximately 2-10 times higher than those in rural areas. An extensive and systematic survey has been undertaken by Tang et al. (2005) to evaluate the PAH contamination of urban soils in Beijing, China. Soil samples were collected from campuses of universities, schools and kindergartens, public squares, fallow land, and roadsides, and were analyzed for 16 PAHs by GC-MS. There was a high variability in the total PAHs (EPAHs) concentrations, ranging from less... 

Kelly, J., Thornton, I., and Simpson, P. R. (1996). Urban geochemistry A study of the influence of anthropogenic activity on the heavy metal content of soils in traditionally industrial and nonindustrial areas of Britain. Appl. Geochem. 1, 363—370. 

From these data, it appears that in areas where PAH concentrations are high, such as the northeastern United States, one can associate the PAH mixtures found with both anthropogenic activity and combustion. There is a possibility that natural combustion, such as forest fires, could contribute to the more remote areas (Maine soil, for example). The contribution of PAH to the offshore sediments (Samples 3, 4, 9) by forest fires should be minimal compared with the anthropogenic contribution because of the proximity of these sites to urban areas and their distance from large forested areas. 

River chemistry is very sensitive to alteration by many human activities, particularly mining and the chemical industries, but also to urbanization as urban wastewaters are much more concentrated than rural streams, and to agriculture through the use of fertilizers (Table 2) (Meybeck et al., 1989 Meybeck, 1996 Flintrop et al., 1996). New sinks are also created such as reservoirs (calcite and silica trapping enhanced evaporation) and irrigated soils, which may retain soluble elements if they are poorly drained. New controls correspond to these anthropogenic influences, such as mining... 

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