Multi-scale spatial characteristics of topsoil PAHs in Tianjin area
天津地区表土PAHs含量的多尺度空间相关性

With the increase of population and the development of agriculture and industry, our human beings are facing more and more serious environmental problems. Polycyclic aromatic hydrocarbons (PAHs) are one of the important global pollutants. Using the method of factorial Kriging, the spatial scale-correlation structure among the 16 types of topsoil PAHs in Tianjin area is discussed in this paper. The results revealed that the pollution process of topsoil PAHs in Tianjin area can be attributed to three spatial scales: nugget scale (0~5km), indicates minor spatial variability which is less than the sample interval; small scale (5~10km), indicates local spatial variability; and large scale (10~50km), indicates regional spatial variability. Significant differences in spatial correlations at different spatial scales among PAHs compounds have been identified. In a word, there exist spatial scale-correlations among these 16 PAHs. This analysis can help to identify the sources and migration/transformation law of the PAHs pollutants in the environment. On the nugget scale,the principal origin of the PAHs may be petroleum source. Because of the errors of determination, the analysis of nugget scale may not reflect the real situation. On the small scale, the principal origin of the PAHs may be the burning of fossil fuels. On the large scale, the principal origin of the PAHs may be the regional deposit from atmosphere.