| Open burning of municipal solid waste（MSW）is a potential non-point source emission,especially in developing countries represented by China.In order to understand the characteristics of the pollutants released by the open burning of MSW and the health risks to human health,this study took rubber and plastics,paper,wood and bamboo,textile and mixed solid waste as the research object,and simulates open burning experiment,measurement and analysis of five kinds of MSW open burning emissions of fine particle matter(PM2.5)levels,and the main pollutants in the PM2.5heavy metals and polycyclic aromatic hydrocarbons（PAHs）levels,distribution characteristics,and to evaluate the health risks associated with heavy metals and PAHs.Research showed that:The composition of MSW affects the pollutants emitted during open incineration.The average concentration ratio of PM2.5produced by open burning of five types of waste:rubber and plastic(11.2±1.8mg·m-3),paper(19.2±1.3 mg·m-3),wood and bamboo(11.2±1.8 mg·m-3)1.0±5.7 mg·m-3),textile type(21.0±1.6 mg·m-3)and mixed garbage(78.5±5.6 mg·m-3).The type and content of pollutants absorbed by PM2.5 were also affected by the incineration components.Heavy metal concentrations produced by paper,rubber and plastic wastes and mixed wastes were higher than that produced by wood and bamboo and textiles;and the concentration of PAHs produced by paper,wood and bamboo,and mixed species were higher than that of rubber and plastics and textiles.The eight heavy metals produced by the same component waste incineration had similar changing trends,which were:Zn>Cu>Mn>Pb>As>Ni>Cr>Cd,and the highest concentration of Zn can reach130.0μg·m-3.The variation of PAHs content was greatly affected by the components without obvious rules.Chr,Bb F,Pyr,Phe and Fla were the higher PAHs content produced by each component.The distribution of the number of PAHs was relatively regular.Except for wood and bamboo waste,the PAHs attached to PM2.5produced by open burning of the other four types of domestic waste were mainly four-ring PAHs,followed by 5 rings,6 rings and 3 rings,with the smallest proportion being the 2 rings.Ba P,DBah A,Bb F,Chr and Ba A were the major contributors to the toxicity of PAHs produced by open burning of MSW.The non-carcinogenic risk of heavy metals in PM2.5emitted from the open burning of MSW to humans was not high,but Cr,Ni,As and Cd had obvious carcinogenic risk to human,the risk of adults was higher than that of children under normal respiratory exposure.From the perspective of waste components,heavy metals produced by paper,rubber and plastic waste had the highest risk,followed by mixed waste,wood and bamboo,and textiles were the lowest.The HQ value of PAHs produced by the five types of MSW in open burning was less than 1,which showed no obvious non-carcinogenic risk to the human body,but the HQ value of Bghi P,Phe,Fla and Pyr was between 10-2～10-1,which could not be ignored.The ILCR values of 7 carcinogenic PAHs produced by open burning of MSW to the human body were all greater than 10-6,indicating that there was a carcinogenic risk to the human body,and the carcinogenic risk of each component was in the order of:mixed type>paper>textile>wood and bamboo>rubber and plastic.In addition,the carcinogenic risk of Icd P,DBah A,Bb F,Ba A,and Ba P to adults exceeded the human body tolerable range of 10-4,and there was a high carcinogenic risk.As a typical carcinogen,Ba P brought the highest carcinogenic risk,and its ILCR value up to 5.1E-03.Heavy metals and PAHs in PM2.5 discharged by open burning of five types of MSW posed health risks to human beings.Wood and bamboo,and mixed wastes had a higher non-carcinogenic risk,and their HQ scores were 4.5 and 3.9.And the risk value was higher than that of children.Pollutants produced by the five types of MSW all have carcinogenic risks to the human body,among which the R-value produced by mixed components of MSW was as high as 3.4E-02,showing a very high risk. |
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