Study On The Distribution And Health Risk Of PCDD/Fs In The Surrounding Environmental Medium Of Municipal Solid Waste Incineration (MSWI)

Along with the economic development, people’s living standard continue growing, theamount of waste generated in our life is increasing rapidly, and the components of wastebecome complex increasingly. Solid waste incineration technology adapt to China’s currentstatus of waste treatment, with the advantage of harmless during high temperatures, volumereduction and weight loss,this technology have been rapidly developed. However, wasteincineration generated secondary pollution, particularly the dioxins toxicity andenvironmental health hazards caused great attention of society.Against this background, our team have monitored the doxin levels of air, soil andvegetation near a municipal solid waste incinerator in Guangdong Province. We have studiedthe content and distribution of dioxins in the surrounding environment medium of the SolidWaste Incineration Plant, furthermore, we have researched the links of dioxin levels betweenthe environmental mediums, as well as carrying out health risk assessment of dioxincontamination characteristics. The main contents and conclusions of the study are as follows:(1)The scope of the dioxin TEQ in the air of study area is0.05~0.27pgI-TEQ/m3, thislevel is lower than the ambient air standard limits (0.6pg I-TEQ/m3) of which is reference toJapan, also lower than ambient air levels of dioxins in most cities in China reported in theliterature. The dioxin toxic equivalents is in the range of0.226~8.775ngI-TEQ/kg in thesoil of the study area, the mean value is2.346ng I-TEQ/kg, lower than the standardagricultural soil standards(10ng I-TEQ/kg) of Netherlands and Switzerland. The dioxin toxicequivalents is in the range of0.785~16.150ngI-TEQ/kg in the vegetation of the study area,the mean value is2.346ng I-TEQ/kg, this value is higher than other literature reported of theplants and crops.(2)The Spatial distribution characteristics of dioxins in the surrounding environmentmedium of the waste incineration plant shows that, the maximum point of dioxins TEQ inambient air is10#,located on the upwind of dominant wind direction. The minimum dioxinsTEQ point is1#in the factory, the dioxins level in the downwind point2#,4#,5#,6#,7#is low,the dioxins level distribution of these point is inconsistent from flue gas emission from wasteincineration plant. These result shows that waste incineration plant is not the only source ofthis region, there are some other sources affected. The maximum dioxins TEQ point of soil ispoint11#, farther from the waste incineration plant. The14#,15#point is in a closed landfill,the TEQ level of this two place is low. In the upwind of the waste incineration point12#,13#,16#is closed to the waste incineration plant, of which the TEQ level is low, showsthat soil near the plant was less affected during the operation of incineration. The vegetationTEQ maximum points is17#(16.150ngI-TEQ/kg), followed by points19#(9.639ngI-TEQ /kg), dioxin concentration of points15#,18#is lower,9#,12#,10#dioxin levels arehigher, but overall, the dioxin concentration in the7sampling point of these vegetation werein a high level. In view of the dioxins in the plant derived from ambient air and soil, while thedioxin level of ambient air and soil in the study area is low, therefore, it requires furtherinvestigation in order to ascertain the dioxins level of the plant in study area.(3) Study on the dioxin fingerprint characteristics of the ambient air near the Solid WasteIncineration plant shows that, the dioxin fingerprint characteristics of the10sampling pointswere inconsistent from waste incineration flue gas and traffic exhaust emissions. Study on thedioxin fingerprint characteristics of the soil near the Solid Waste Incineration plant shows that,the dioxin fingerprint characteristics of the7sampling points were inconsistent from ambientair and research information. Study on the dioxin fingerprint characteristics of the vegetationnear the Solid Waste Incineration plant shows that, the vegetation dioxin fingerprintcharacteristics of the7sampling points showed a similar distribution with the ambient air andsoil but also there are differences. It shows that the dioxin sources of the environmentalmedium surrounding the MSWI are various and complex.(4) Source analysis of ambient air dioxins in the study area shows it is not only affectedby MSWI and traffic emissions, but also some other sources. Source analysis of the soilsamples shows that, the dioxin sources of these points were similar, the affection of the trafficemission shows higher than the MSWI to the soil dioxin level, there may also be affecting byother emission sources.(5) The range of the dioxin breathing exposure to adults in the study area is0.011~0.057pg I-TEQ/(kg·d), The range of the dioxin breathing exposure to children in thestudy area is0.019~0.102pg I-TEQ/(kg·d). The breathing exposure of the children is almosttwice as adults, indicating that children are more vulnerable to the threat of dioxin in theenvironment. The ratio of standard concentration range of the adults and children isrespectively0.271%-1.150%and0.480%-2.539%, Far below the10%of the human tolerabledaily intake of breath as the evaluation of the level of exposure limits, at an acceptably lowlevel.