| Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) is a typical semi-volatile persistentorganic pollutants and people has been paid more attention to it for its strong carcinogenic,teratogenic and mutagenic. Dioxins from the source entered into atmosphere by diffusing,entered into soil and water through the dry and wet deposition and entered the plants throughadsorption of leaves. With the trophic level of the food chain increasing, it showedbiomagnification accumulation and biological. The study aimed at the increasingly seriousenvironmental problems in the Pearl River Delta region, choosed two typical municipal solidwaste incinerator （MSWI） in South China. Through setting up scientifically arrangement ofmonitoring points, monitored environmental characteristics of dioxins, detection levels,analysed distribution characteristics of dioxin in different media and analyse the possiblesources. With the aid of excellent experimental conditions, determination of dioxin content ofisotope dilution mass spectrometry with internal standard method was carried out by usingHRGC/HRMS, which ensured the data accurate and reliable. This study analyzed42atmospheric samples,14soil samples and14plant samples at14positions of zone A and5airsamples,6soil and6plant samples of zone B. The main conclusion were as follows：（1）The concentrations of2378-PCDD/Fs of air sampling area A were in the range of0.156~1.44pg I-TEQ/m~3, with the average concentration as0.426pg I-TEQ/m~3, theconcentrations of2378-PCDD/Fs of air sampling area B were in the range of0.0503~0.148pgI-TEQ/m~3, with the average concentration as0.111pg I-TEQ/m~3and the levels of samplingsites A and B were lower than the ambient air standard of0.6pg TEQ/m~3for dioxins proposedby Japan;Compared with Beijing (0.268pg I-TEQ/m~3), Shanghai (0.268pg I-TEQ/m~3) andGuangzhou (0.364pg I-TEQ/m~3), A study area was at the same level,the B study area werelower than that of level. The concentrations of2378-PCDD/Fs of the soil sampling area Awere in the range of0.66~7.11pg I-TEQ/g, with the average concentration as2.99pg I-TEQ/g,the concentrations of2378-PCDD/Fs of the soil sampling area B were in the range of3.71~20.1pg I-TEQ/g, with the average concentration as9.66pg I-TEQ/g; A study area aroundthe point were lower than the sensitive standard limit (10pg I-TEQ/g) proposed by Swedish,but almost all points were slightly beyond the provisions of Holland agricultural soil standard(1pg I-TEQ/g), the soil of B area was polluted at a higher level; The concentrations of2378-PCDD/Fs of the plant sampling area A were in the range of6.18~61.0pg I-TEQ/g, withthe average concentration as20.9pg, which matched the Japanese pine needles pollutionlevels (23.49pg I-TEQ/g). The concentrations of2378-PCDD/Fs of the plant sampling B areawere in the range of1.32~13.2pg I-TEQ/g, with the average concentration as5.37pg I-TEQ/g,which matched banyan leaf level (4.92pg I-TEQ/g) of Taiwan.（2）For the higher emission source (112.4ng I-TEQ/m~3), it showed a high level ofpollution in some points around ambient air. The content of PCDD/Fs of incineration plant dominant wind in the atmosphere was higher. For the emission source (0.171ng I-TEQ/m~3)with a general level, the impact on the surrounding environment was not obvious and thePCDD/Fs pollution was lower than the general level of city in our country;（3）For the air samples,1,2,3,4,6,7,8-HpCDF and OCDD were the main dominantcomponents,2,3,4,7,8-PeCDF was the most contribution rate of monomer toxicity equivalentof dioxin in all samples. The OCDD was the most concentration contribution for soil samples,meanwhile2,3,4,7,8-PeCDF and OCDD were two large contributors;2,3,4,7,8-PeCDF wasthe largest monomer toxicity equivalent of dioxinin in all plant samples;（4）Principal component analysis (PCA) statistical methods were used for the studyarea, and the results were as follows: some air points were significantly affected by MSWI,while other sites may be affected by other sources (such as traffic source). Soils wereinfluenced by traffic emissions significantly, some points of plant were affected by bothMSWI and CI, showing a performance of the joint action by multi-source. For the B studyarea, the effects of MSWI on each medium was not very significant;（5）The incineration technology reformed and it has stopped running for a year.7typical points were selected for atmospheric monitoring, analysing the concentrations anddistribution characteristics. Compared with the prior results, it can be obtained in the studyarea: traffic source was an important source of dioxin pollution in the atmosphere. Meanwhile,the CI also had a certain contribution, which further inspected the previous conclusion;（6）The potential dioxin inhalation exposure dose was0.021~0.190pgI-TEQ/kg for theadult and0.028~0.250pg I-TEQ/kg for the children in A study area, also potential dioxininhalation exposure dose was0.00495~0.0145pgI-TEQ/kg·d for the adult and0.00874~0.0257pg I-TEQ/kg·d for the children in B study area. Compared the intake into thebody of dioxin by breathing with tolerable daily intake by10%evaluation standard, adult andchildren’s respiratory exposure levels were at a safe level in two areas, relative to the adult,children would be withstand a higher respiratory exposure dose. |
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