| Polycyclic aromatic hydrocarbon(PAHs),as a kind of typical persistent organic pollutant, is one of important carcinogenic substances in the environment. PAHs are the ubiquitous environmental pollutants that have been detected in various matrices, such as water, soil, crop and food. PAHs pollution has characteristics of toxin(carcinogenic, teratogenic and mutagenic), residue and bioaccumulation. Therefore, the research of PAHs pollution has caused wide public concern.The research on the indoor environmental pollution is being paid more and more attention since we generally spend more than 80% of our time indoors. Settled dust, as atmospheric sediment, is an important indicator that can reflect atmospheric pollution. The damage of settled dust to the ecosystem is conceal, potential and long-lasting. Settled house dust, as the carrier of various pollutants, can induce a variety of diseases by inhalation and ingestion either directly or indirectly. So far, there are only few studies on PAHs pollution in house settled dust, especially in West China. Since the strategy of “western development ” was established, the western economic society has been greatly developed, howerver, the following environmental problem will be more prominent. So, it is significant for the coordinate development between economy and environment, to grasp first-hand material of PAHs polltion, to understand its space distribution, to explore its influence factor and to build its reasonable early warning system.So in this thesis, the study of PAHs pollution in settled house dust were carried out on the current situation, the seasonal variations, the regeonal distributions and the risk characteristics, since the related researches were scarce in West China. Based on the above research results, the early warning system for PAHs pollution was established. Main contents can be summarized as follows:The researches on the method and theory for early warning system of PAHs pollution in settled house dust were involved in the first part. With the complicated composition and various species of PAHs, efficient method of overall monitoring hundreds of PAHs compounds was not available currently. To overall monitor PAHs pollution, the fingerprint identification theory was introduced and the theoretical framework of early warning system for PAHs pollution was presented, by adopting statistical method and modern chromatographic analysis technology.The second part, was the research on the pollution status and distribution characteristies. To realize the construction of early warning system, 18 kinds of PAHs, which were international required strict control, were selected. The concentration level, space distribution, seasonal variation and influencing mechanism of selected PAHs were anlysed to provide the important basis for the following construction of early warning system.In this part, the method to quantitatively analysis the concentrations of 18 kinds of PAHs by HPLC(the high-performance liquid chromatography) was developed. The method showed a good linear correlation inside the scope of 0.2-2.0 μg. The correlation coefficient were greater than 0.9992. The detection limit and the quantitative limit are 6.18-12.58 ng and 20.6-41.93 ng, respectively. The average recovery of PAHs composition is in the scope of 91.61%-102.81%, with RSD value(relative standard deviation) of 1.06% to 3.24%.Then the constructed analysis method was used to measure the PAHs concentrations of settled dust samples collected from all 9 regional administrative regions in Guizhou(involving 13 cities, 22 towns and 52 villages) in 2012 and 2013. The result showed that the average concentration for Σ18PAHs is 1.61 μg·g-1, and the Σ18PAHs concentrations in different administrative regions were obviously different. Most of them are high molecular weight PAHs(4-6 rings), especially for PHE、FLT and PYR.Based on the analysis results for pollutionstatus and pollution characteristics of 18 kinds of PAHs compounds, the space distribution and seasonal variation were further studied. The result showed that the Σ18PAHs concentration in winter was significantly higher than that in summer and the vast use of coal and biomass in winter was the possiblereason. In comparison, the change of the Σ18PAHs concentrations of different administrativeregions was close accord with thatof population density with a linearly dependent coefficient of 0.91, which showed that human activity was a important driving factor of PAHs levels distribution. The Σ18PAHs mean concentrations in cities, towns and villages were obviously different, and the concentration in city was 1.6 times that in town and 2.7 times that in villages. While, compared to cities and towns, the villages would face greater dual pressure from the environment and economic development. The optimal scale regression model indicated that the factors of the administrative regions, urban and rural areas, sampling seasons, sampling floors and the distances to the main road were the important influence factors for PAHs distrabution, and the factors of the administrative regions and urban and rural areas had largest influences on PAHs concentration in settled house dust.The third part, was the research on sources apportionment and the exposure risk assessment. The results could provide a scientific basis for developing standards of environmental protection. The sources of PAHs were analyzed with methods of characteristic compound ratio and multivariate statistical analyses. The result showed that the PAHs pollution in settled house dust was affected by both ourdoor and indoor environment, and the sources of traffic emission and coal-fired emission had thegreatestinfluence on the PAHs concentration in settled house dust. In cities the sources of coal-fired emission were mainly from outside, and in villages there is a indoor source of coal combustion which can emit PAHs to indoor environment directly. Lifetime cancer risk(ILCR) model was used to assess the health risk of PAHs exposure, and it was found that Cancer risk caused by breathing intake was far less than the ways of skin contact and dust ingestion. In general, the ILCRs of children resulted from PAHs pollution of settled house dust was higher than that of adults. The result of uncertainty analysis by Monte Carlo simulation showed that children were more sensitive to the exposure duration to PAHs in settled house dust.The fourth part introduced theoperation case of PAHs early warning system. Based on the results of theory study and data analysis mentioned above, the PAHs early warning system was established for Guizhou province. In this part, the fingerprint acquisition method was established, and the fingerprints database, including 27 characteristic fingerprints, was achived. The early warning system is composed of 5 core modules such as fingerprint acquisition, characteristic fingerprint extraction, fingerprints database, data matching and result output. At the same time, a case study of Guiyang was given to verify the feasibility of PAHs early warning system. |
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