Research On Dioxin Pollution In Ambient Air In Automobile Casting And Waste Incineration Plants

The dioxins is a kind of important pollutant, which is extremely toxic and has the characteristics of stability and can accumulate in living organisms easily, etc. It can cause potential effects on human health when human was exposed to dioxins. In recent years, our country have paid more and more attention to the pollution concentration and characteristics of dioxins and the risk to human health. The melting-casting industry and incineration industry are the two main industries of dioxins pollution emission in our country, and there are many of workers in those industries.To investigate the dioxin pollution in the air of the workshops, an automobile foundry and two MSWI was selected as the research objects in this study, which were the main industries of dioxins pollution industries in the area. To investigate the air pollution level, characteristics, the pollution sources and occupational inhalation exposure of PCDD/Fs in the industries, fine particles and gas phase of air in workshops, nearby residential areas and remote background area were collected and analyzed. The main research results are as follows:(1)For I-TEQ concentration, the results of all the air sampling points in the foundry were lower than the ambient air quality standards. The mean value of the workshops was 0.282 pg I-TEQ/m3 and the highest value was found in the cadmium mineralization zone, and PCDFs were the major dioxins pollutant in the foundry workshops.(2)The value of the MSWIs ranged from 0.034?2.152 pg I-TEQ/m3, most of them were higher than the ambient air quality standards. And the area behind the incinerator had a high I-TEQ. OCDD and 1,2,3,4,6,7,8-HpCDD were the main homologues. For MSWI A, the flue gas and the fly ash had major effect on PCDD/Fs, while the dioxins pollution in MSWI B only effected by the fly ash.(3)Estimated occupational inhalation exposure dose to PCDD/Fs ranged from 0.02-0.25 pg I-TEQ/(kg·d) in the different workshops in the foundry, which were all lower than the limit value. The workers in the cadmium mineralization zone were bearing the highest PCDD/Fs exposure risk in the factory, and workers in the foundry workshops were in low risk of non-cancer, but the risk of cancer exceeded the acceptable level.(4) Estimated occupational inhalation exposure dose to PCDD/Fs ranged from 0.01?1.10 pg I-TEQ/(kg-d) in MSWIs, the some exposure of the individual value exceeded the limit on breathing exposure assessment, and the staff quarter area in A and the zone behind the incinerator B had the highest exposure level. The the non-cancer indexs in MSWIs were not high, but some workers had a medium risk of cancer.