[Pollution Characteristics and Emission Factors of PCDD/Fs from Iron and Steel Industry].

The pollution level, emission characteristics, and emission factors of PCDD/Fs from a number of steel plants were investigated in a particular province of China. The results showed that the concentration of PCDD/Fs was at a low level and decreased by 1-2 orders of magnitude compared with that in 2005-2019. In detail, the concentrations of PCDD/Fs ranged from 0.003-0.557 ng·m-3(I-TEQ), and the mean value was 0.165 ng·m-3 for the sintering process. Moreover, the concentrations of PCDD/Fs ranged from 0.006 to 0.057 ng·m-3, and the mean value was 0.025 ng·m-3 for the electric furnace process. In addition, the concentration of PCDD/Fs in the iron and steel industry from 2005 to 2020 increased first and then decreased, especially after the implementation of the new emission standard and the ultra-low emission control of conventional pollutants such as smoke, showing a significant decline. The results of fingerprint analysis showed that 2,3,7,8-TCDF was the largest congener contributing to the mass concentration, and lower chlorinated PCDFs were increased. This result differed from those of previous studies in which highly chlorinated PCDFs and PCDDs dominated, indicating that the generation source of PCDD/Fs had changed. The congener and isomer profiles of PCDD/Fs in flue gas from the sintering process were similar to those in the flue gas from the electric furnace process. Additionally, showing the characteristics of the typical high-temperature thermal process, the de novo synthesis may be the dominant mechanism of formation of PCDD/Fs in the sintering process and electric furnace process. The emission factor was 0.003-0.5 µg·t-1 (I-TEQ), and the average emission factor was (0.18±0.22) µg·t-1 for the sintering process. The emission factor was 0.04-0.5 µg·t-1, and the average emission factor was (0.27±0.23) µg·t-1 for the electric furnace process. These values were far lower than those of the standard toolkit for identification and quantification of dioxin and furan emissions released by UNEP in 2013 and the emission factors in the dioxin emission inventory of China in 2004. It is suggested that the emission factors of PCDD/Fs in the iron and steel industry of China should be studied and updated.

[Discussion of Emissions and Health Risk of Polycyclic Aromatic Hydrocarbons (PAHs) from the Retreading Process of Waste Tires].

The emissions characteristics of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) in ambient air during the waste tire retreading process (open-air storage, mixing, vulcanization, and grinding processes) and in workers' dormitory were analyzed. In addition, the occupational health risk of the workers was evaluated. Results showed that PAHs were detected in all retreading processes and in the workers' dormitory. The highest concentration site was the mixing process, followed by open-air storage and vulcanization process. The lowest concentration point was in the grinding process. The average concentration of PAHs in the workers' dormitory was 11.1 ng·m-3. The PAHs at all sampling points were largely phenanthrene (Phe), fluoranthene (Flu), anthracene (Ant), and pyrene (Pry), which also had a stronger linear correlation with the total PAH concentration. An analysis of the benzene rings showed that three ring and four ring were the majority, while two ring, five ring, and six ring components accounted for less than 10%. Results of the possible influencing factors of the PAHs revealed that the open-air storage and dormitory might be affected by a combustion source, but the mixing, vulcanization, and grinding processes might be affected by rubber oil. The principal component analysis (PCA) and cluster analysis showed that the spatial location of all sites would significantly influence the distribution of PAHs during the tire retreading process. The health risk assessment showed that occupational workers had a lower risk of lifelong cancer, and there was little influence on life expectancy.

[Possible Sources of PCDD/Fs in Atmosphere of a Certain District in Guangdong].

This paper analyzed 17 polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs) by HRGC/HRMS in the flue gas of a certain municipal solid waste incinerator(MSWI) and its surrounding air and other possible sources in Guangdong. It discussed the feature of homologs and main toxic monomers in all samples. It also investigated the relationship among surrounding area, MSWI and possible sources using principle component analysis (PCA) and cluster analysis. The results showed that the concentration of PCDD/Fs was higher in the flue gas than the ambient air, moreover non-effect suffered by prevailing wind direction. The possible sources might be tyre factory and open burning based on spot survey. The concentration of PCDD/Fs was lower in tyre factory than upwind station, but higher at open burning spot than outdrop monitoring station. The analysis of homologs showed that OCDD, 1,2,3,4,6,7,8-HpCDD and 1,2,3,4,6,7,8-HpCDF were the main materials in the flue gas and air, meanwhile OCDF was also found in atmosphere. There was similar feature of 17 PCDD/Fs between surrounding monitoring station and tyre factory, and the same between flue gas and open burning. The further analysis showed that the linearly dependent coefficients of 1,2,3,7,8-PeCDD and 2,3,4,6,7,8-HxCDF were 0.95 and 0.75, respectively. It showed the strong correlation of two monomers in all ambient air samples. The PCA and cluster analysis showed that MSWI influenced the surrounding air, tyre factory had an impact on upwind station, and open burning had a lower effect on outdrop monitoring station.

[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.

[Internal Exposure Levels of PAHs of Primary School Students in Guangzhou].

In order to investigate the internal exposure levels of polycyclic aromatic hydrocarbons (PAHs) in primary school students of Guangzhou, the research collected urine of 78 and 86 primary school students from two primary schools in the summer of 2014, one school located in the ordinary residential area and the other in the industrial area. The contents of 10 kinds of OH-PAHs were tested by the rapid liquid chromatography coupled to triple quadruple tandem mass spectrometry. The results showed that the concentrations of total OH-PAHs in primary school students in the residential zone ranged from 0.83 µmol · mol⁻¹ to 80.63 µmol · mol⁻¹, while those in industrial area ranged from 1.06 µmol · mol⁻¹ to 72.47 µmol · mol⁻¹. The geometric average concentrations were 6.18 µmol · mol⁻¹ and 6.47 µmol · mol⁻¹, respectively, and there was no statistical significance between them (P > 0.05). Comparison of the exposure levels of different components of PAHs in the two areas found that all the OH-PAHs had no significant difference except for the levels of 1- OHP (P < 0.05). We should also pay attention to the higher exposure levels of PAHs in both areas when compared with other researches. In addition, the OH-PAHs in primary school students in the ordinary residential area had a good correlation between 0. 511 and 0.928 (P < 0.01), whereas there was no correlation between 1-OHP and 2-OHN, 1-OHN in the primary school students in the industrial area and other OH-PAHs had relatively weak correlation ranging from 0.338 to 0.855 (P < 0.01). This difference might indicate different pollution sources of PAHs in different functional areas, which was relatively single in the residential area, while the industrial area was polluted by multiple sources of industrial enterprises and logistics transportation emissions.

[Emission of PCDD/Fs from Crematories and Its Influencing Factors].

To analysis the influencing factors for the emssions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) as structure of crematory, air pollution control device (APCD) and funeral objects, etc, we collected and measured the PCDD/Fs emissions in flue gas from 13 crematories in China. Then we proposed some supervision suggestions on measures of pollution control and management. The results indicated that the emission levels of PCDD/Fs (as the toxic equivalent concentration, TEQ) was ranged in a large gap from 0.027 to 15.8 ng x m(-3), and the average was 3.2 ng x m(-3). Emissions factor of PCDD/Fs (as TEQ) from 13 crematories varied between 45.9 and 22 236 ng x body(-1), and the average was 4 738 ng x body(-1). The emissions of PCDD/Fs from flat incinerators were generally lower, whereas higher ratio up to the national discharge standard, than that of car type incinerators. Congener distribution of PCDD/Fs in flue gas from 13 crematories were different from each other. Since the emission of PCDD/Fs from some crematories remains in high level, it is necessary to control pollution from the source, improve the pollution control technology, and strengthen government supervision, by following measures: 11 cremating funeral objects separately from corpse; 22 adding one

[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.

[Concentrations, distribution characteristics and electron beam radiolysis degradation of PCDD/Fs in waste water from a paper mill].

Concentrations and distribution characteristics of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (2,3,7,8-PCDD/Fs) were analyzed in waste water from a paper mill. And concentrations of 2,3,7,8-PCDD/Fs in waste water before and after electron beam irradiation with different doses were compared. The feasibility, mechanism and rates of 2,3,7,8-PCDD/Fs degradation were discussed. The PCDD/Fs concentrations and corresponding I-TEQ (toxic equivalent quantity) values were 239 pg x L(-1) and 41.0 pg x L(-1), respectively, in the waste water. The concentrations of total 2,3,7,8-PCDD/Fs decreased after electron beam radiolysis at a dose of 30 kGy and 60 kGy with degradation rates of 5.27% and 23.6%, respectively.

[Seasonal variation of concentrations and distribution characteristics of PCDD/Fs in atmosphere of an industrial area, Guangzhou].

Atmospheric concentrations of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were measured seasonally in an industrial area of Guangzhou City. And seasonal variation of concentrations and distribution characteristics of 2,3,7,8- PCDD/Fs was investigated. The PCDD/Fs concentrations and corresponding I-TEQ (toxic equivalent quantity) values were in the range of 2.33-75.4 pg x m(-3) (mean = 23.2 pg x m(-3)) and 0.229-10.7 pg x m(-3) (mean = 2.00 pg x m(-3)), respectively. The seasonal variation of PCDD/Fs concentrations was obvious, with the highest concentration was found in spring (37.8 pg x m(-3)) and the lowest in summer (13.5 pg x m(-3)). However, no obvious difference of concentrations was observed for autumn (22.3 pg x m(-3)) and winter (19.1 pg x m(-3)). The seasonal variation of I-TEQ values is as follows: spring (5.58 pg x m(-3)) > summer (1.06 pg x m(-3)) > autumn (0.839 pg x m(-3)) > winter (0.525 pg x m(-3)). The influences of monsoon and rainfall on the concentration of PCDD/Fs in atmosphere are discussed.

[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.

[Preliminary study of PBDE levels in house dust and human exposure to PBDEs via dust ingestion].

Fifty-two house dust samples were randomly collected in Guangzhou and Haikou City, to analyze the concentrations of Sigma10 PBDEs (sum of BDE 28, 47, 66, 85, 99, 100, 153, 154, 183 and 209), the PBDE composition profiles, and possible influencing factors, and estimate human exposure to PBDEs via dust ingestion for adults and toddlers. The results showed that PBDEs were found in all samples, with the Sigma10 PBDEs concentrations ranging from 544.2 ng/g to 9 654 ng/g, and with median (mean) of 2 547 (3 096) ng/g. The PBDE levels in Guangzhou samples were obviously higher than those in Haikou. No significant correlations between PBDE levels and residential characteristics (number of TVs, computers, and polyurethane foam-contained furniture, time of using TVs and computers) were observed. BDE209, with a mean concentration of 3 021 ng/g, was the dominated congener, contributing 73.70%-99.74% to the Sigma10 PBDEs, with a mean contribution of 96.85%. BDE 47, 99 and 183 were the most abundant congeners of Sigma9 PBDEs (BDE 209 excluded), with a mean contribution of 24.48%, 23.99%, and 21.66%, respectively. There is no notable difference in PBDE composition between Guangzhou and Haikou samples. The estimated exposure for adults and toddlers to PBDEs ranged from 10.59 ng/d to 254.7 ng/d and from 140.1 ng/d to 509.3 ng/d, respectively. Due to their increased dust ingestion rates, toddlers in took more PBDEs via dust ingestion than adults. Dust ingestion was an important human exposure route for PBDEs, especially for toddlers.

[Content analysis and assessment of polycyclic aromatic hydrocarbons in surface sediments from Beijiang River, China].

In the present study, 16 polycyclic aromatic hydrocarbons (PAHs) in the surface sediment from Beijiang River in China were quantitatively determined by GC/MS. The concentration of PAHs varied from 38.2 to 6470 ng x g(-1) dry weight, with average 1071 ng x g(-1), which was in moderate level compared with other rivers in Pear River Basin. The PAHs distribution in Bejiang River was obviously affected by point source emissions. The high PAHs concentrations of 6470 ng x g(-1) and 4 470 ng x g(-1) were found at the outfalls of Shaoye and the Shakou town, respectively, where PAHs probably derived from local mining/smelting and related industrial actives. The ecological risk of surface sediment in Beijiang River was assessed with the methods of sediment quality guidelines (SQGs), sediment quality standards (SQSs) and contamination factors (CFs) . The result shows that the adverse biological toxicity effect might occasionally happen in more than half of sampling stations. By comparison with the background area, the contamination degrees of PAHs in 20 sampling stations were at very high level, which should arrest the local governments' attentions. The highest ecological risk areas occurred at the outfalls of Shaoye and the Shakou town in which the ecological risks derived from PAHs were within between probable effect level (PEL) and frequent effect level (FEL). The future research was suggested mainly focusing on the status of benthos, sources of pollutants and ways to control pollution in high-risk areas.