No abstract

No abstract

No abstract

Soil contamination with polycyclic aromatic hydrocarbons is an increasing problem and has aroused more and more concern in many countries, including China. In this study, representative soil samples (n = 87) of suburban areas in Tianjin (Xiqing, Dongli, Jinnan, Beichen) were evaluated for 16 polycyclic aromatic hydrocarbons. Surface soil samples were air-dried and sieved. Microwave assisted extraction was used for polycyclic aromatic hydrocarbons preparation prior to analysis with gas chromatography-mass spectrometry. The total concentrations of tested polycyclic aromatic hydrocarbons in Xiqing, Dongli, Jinnan, Beichen ranged in 58.5-2,748.3, 36.1-6,734.7, 58.5-4,502.5, 29.7-852.5 ng/g and the averages of total concentration of polycyclic aromatic hydrocarbons were 600.5, 933.6, 640.8, 257.3 ng/g, respectively. Spatial variation of polycyclic aromatic hydrocarbons in soil was illustrated; Pollution status and comparison to other cities were also investigated. Serious polycyclic aromatic hydrocarbons soil pollution was found in Dongli district, on the contrary, Bap in most sites in Beichen did not exceed relative standards and most sites in Beichen should be classified as non-contaminated soil. Principal component analysis was used to identify the possible sources of different districts. It turned out that coal combustion still was the most important sources in three districts except Beichen. Coking, traffic, cooking, biomass combustion also accounted for polycyclic aromatic hydrocarbons pollution to certain extent in different districts. These data can be further used to assess the health risk associated with soils polluted with polycyclic aromatic hydrocarbons and help local government find proper way to reduce polycyclic aromatic hydrocarbons pollution in soils.

Xuanwei and Fuyuan are located in the southwest of China and have the highest lung cancer incidence in China, possibly even highest in the world. Dietary samples were collected from these two counties and the contamination status of sixteen polycyclic aromatic hydrocarbons (PAHs) were determined. PAH components, food constituents, dietary exposure level, as well as spatial difference, were studied in the different groups. The percentage of dietary intake to total intake of PAHs was calculated and the relationship between the dietary intake of PAHs and the abnormal lung cancer incidence was primarily discussed. The results showed that rice and potatoes were the main foods of the local residents in Xuanwei and Fuyuan. The daily exposure doses of Bap (benzo[a]pyrene), total PAHs, and TEQs (toxic equivalents) based on Bap toxicity in two counties were estimated to be 458 ng d(-1), 14,532 ng d(-1), and 896 ng d(-1), respectively, which were much less than those in other cities reported previously. The lower ingestion amount of food with a relatively higher content of PAHs, such as meat and fish, could account for the lower exposure doses. PAHs with less than 4 rings occupied a high percentage of the total PAHs in food samples. The exposure doses varied significantly among different sites and even different families at the same site. Dietary exposure was not the main exposure route of PAHs at most sites. It appears that there was not a direct relationship between dietary exposure and the lung cancer incidence. However, high ratios of dietary intake to total PAHs intake (1.33%-70.61%) were found in several areas and rational diet suggestions should be given in these areas in the future.