| Polycyclic Aromatic Hydrocarbons(PAHs) consist of two or more benzenoid-rings, which can be formed by the incomplete combustion of pyrolysis of organic materials containing carbon and hydrogen such as coal, petroleum, wood, macromolecule organic materials, tobaccos. PAHs are ubiquitous environmental pollutants that represent the largest class of suspected chemical carcinogens, and are hence of great concern due to their toxic effects, persistence and bioaccumulations. To protect humans against noxious environmental pollution, it is very important to know the characteristics of level, sources and fatal of PAHs in the environment. Guiyang city is located in a basin of the southwest of China, where coal is the main energy sources, and vehicle increase fast in recent years. Fourteen priority polycyclic aromatic hydrocarbons(PAHs) were determined in the airborne particles, soils, river and lakes in this study. The main conclusions have been reached as followings:1. A sensitive, rapid and accurate method for extraction and determination of US EPA 14 priority pollutant polycyclic aromatic hydrocarbons (PAHs) from samples has been developed by modification of conventional method in this study. This method is only based on sonication extraction with dichloromethane (DCM) and purification by silica gel for airborne particles, soil samples, and solid-phase extraction for water samples. The separation and determination of PAHs is carried out by high performance liquid chromatograph (HPLC) by using gradient elution and fluorescence programmed multiple wavelength shift detection.2. The variation characteristics of composition and concentration of PAHs in airborne particles, rain water, lake, river and soils in Guiyang were investigated. Fourteen PAHs concentrations range from an amount under detection limit (nd) to 72.3ng/m~3 in airborne particles, and total fourteen PAHs concentrations vary from 6.02ng/m~3-80.2ng/m~3 in twelve months. Total PAHs concentrations vary from 76.9-1108 ng/L in rain water and the average concentration is 274 ng/L. Totalconcentrations in Nanming River, Aha Lake, Hongfeng Lake are 231, 266, 177ng/L, respectively. Total fourteen PAHs concentrations range from 59.6-1437ug/kg in soils. It is clear that 5-and 6-ring PAHs dominated total PAH burden in airborne particles and soils, but on average 2-3-4-ring PAHs is dominant in total PAHs burden in waters.3. In airborne particles, higher concentration of total PAHs, TSP and total PAHs/TSP were found in winter and spring samples than in summer and fall samples. Good correlations of the investigated particle- bound PAHs were found with TSP. A correlation analysis was performed between concentrations of total PAHs, TSP, total PAHs/TSP and meteorological data simultaneously monitored. Total PAHs, TSP were found to negatively correlate with relative humidity, while total PAHs/TSP positively correlated with relative humidity. Correlations of particle-bound PAHs and total PAHs/ TSP with temperature are weak. More fine particle were easily washed away than coarse particle in rain, hence concentrations of PAHs and TSP were lower but total PAHs/TSP were higher in rain. The highest PAHs concentrations were obtained when the wind was from south, and the lowest PAHs concentrations were obtained when the wind was from north, while PAHs concentrations were in the middle when the wind was from east.4. Correlations between total PAHs concentrations and the temperature, humidity, pH are poor in rain water, and also correlations of total PAHs concentrations with precipitation rain fall are weak. The characteristics of hydrodynamics have more influence on total PAHs concentrations in Aha Lake, Nanming River, and Hongfeng Lake. Higher PAHs concentrations wi rain water were obtained when the wind was from north than south. PAHs in Aria Lake are mainly originated from waste water from coal mine, chemical works and residential area, while PAHs in Hongfeng Lake mainly polluted by atmospheric deposition. Waste water from factories and residential area surrounding are major sources of PAHs in Nanming River. Rain water may also contribute to PAHs compounds in Aha Lake, Nanming River, and Hong feng Lake.5. This study shows obviously different PAHs levels in urban and suburban airborne particles and soil samples. Generally, concentration of PAHs was higher in urban samples than in suburban samples, while PAHs concentration was higher insuburban samples near to factories locations than in urban samples. Similar to other cities worldwide, PAHs levels in airborne particles and soil in Guiyang city were higher than most cities in other countries but lower than most cities in China. Accordingly, it can be concluded that the soil in Guiyang city has been contaminated by PAHs at a medium level.6. Coal combustion and traffic exhaust sources, and correlation coefficient matrix of the concentration of different PAH ring (2+3-ring, 4-ring, 5-ring, 6-ring) of different sample sites were used to evaluate the possible PAHs sources. Coal-burning were thought to be the major source of airborne particle-associated PAHs in Guiyang city, and traffic exhaust also did some contribution to airborne particle-associated PAHs. Soils around the Guiyang city may have been dominantly polluted from diffusion of coal-combustion and traffic exhaust.
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