[Dioxin Pollution and Occupational Inhalation Exposure of PCDD/Fs in Municipal Solid Waste Incinerator].

To assess the pollution levels, characteristics, and the pollution sources and occupational inhalation exposure of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)in the workshops,ambient air samples in different types of incinerators of two municipal solid waste incinerators(MSWI) were collected and analyzed. The results showed that ① The I-TEQ concentration ranged from 0.034-2.152 pg·m-3in the two waste incineration plants, and the most sites' I-TEQ exceeded the ambient air quality standard. Besides, the I-TEQ concentration behind the incineration plant was higher than others. ② The dioxins in incineration plant were dominated by OCDD and 1,2,3,4,6,7,8-HpCDD. For MSWI A, the flue gas and the fly ash had major effect on PCDD/Fs, while the dioxins pollution in MSWI B was only affected by the fly ash. ③ Occupational inhalation exposure of PCDD/Fs was 0.01-1.10 pg·(kg·d)-1 in incineration plant, some occupational inhalation exposure values exceeded the evaluation standard, and the areas behind the incinerators were evaluated to have a high exposure risk.

[Effect of meteorological factors on characteristics of PCDD/F pollution in Guangzhou].

High-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) was used to measure contents of 2, 3, 7, 8-polychlorinated dibenzo-p-dioxin and furan (PCDD/F) in ambient air in Guangzhou city, and its sources were traced and tracked preliminarily. Spatial and seasonal distributions, the correlation between PCDD/F concentrations and various kinds of meteorological factors were studied with emphasis, as well as the trajectory of air mass simulated by hybrid single-particle lagrangian integrated trajectory (HYSPLIT) model of the U. S. A Air Resources Laboratory, which will provide important basic data for understanding PCDD/F pollution levels in urban regions. The results show, PCDD/F concentrations in the industrial area are higher than others, and in spring, PCDD/F TEQs are the highest. Meteorological factors, like wind direction and speed, temperature, air pressure, relative humidity, precipitation all have influence on pollution levels of atmospheric PCDD/Fs. Temperature and wind speed has a negative correlation with the concentration, but it is not obvious. By the analysis of the backward trajectory of air mass, something are obtained that the trajectory extends mainly to northwest areas in autumn, and air masses from inland migrate slowly in winter, while they arrive at Guangzhou after passing southeast coast or sea.

[Concentration, profile distribution and source identification of PCDD/Fs in environmental medium around a HSWI].

The concentration and profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the environmental air, soil and plant samples around a hospital solid waste incinerator (HSWI) in Northwest of China were determined by HRGC/HRMS, and the flue gas samples of the HSWI were also involved. The results showed that the average concentration (I-TEQ) of PCDD/Fs in the exhaust gas was 184 ng x m(-3), which seriously exceeds the emission standard (0.5 ng x m(-3)). And the average concentration of PCDD/ Fs was 7.30 pg x m(-3) in the ambient air samples, 52.5 pg x g(-1) in the soil samples, and 146 pg x g(-1) in the leaves samples. All of them were at quite high levels. The concentrations of PCDD/Fs in air samples of downwind were obviously higher than those of upwind. The concentration increased and then decreased with the increase of distance from the HSWI, and the highest concentration occurred at the distance of 700 m from the HSWI. The mass concentration (I-TEQ) proportional distributions of 2, 3, 7, 8 substitution toxic dioxins in downwind air and soil samples was similar to those in the exhaust gas samples. The analysis results of PCDD/Fs concentrations, profiles distributions and principal components all showed that the major source of PCDD/Fs in this area was from the HSWI flue gas emissions.