Health risk assessment of polychlorinated dibenzo-p-dioxins polychlorinated dibenzofurans (PCDDs/PCDFs) regarding municipal solid waste incineration

Incineration carries significant weight in waste disposal in general. Seventy-five percent of the total quantity of municipal solid waste (MSW) is incinerated. In the year 1994, there were a total of 1854 incineration plants for MSW and 3376 incineration plants for industrial waste in Japan. But air pollution by exhaust substances -especially dioxin- from incineration plants poses a problem. This may place a big hurdle before future incineration plant projects. The study team on the risk assessment set by the Ministry of Health and Welfare (M.H. & W.) proposed 10 pg.Toxic Equivalents (TEQ)/kg/d as a Tolerable Daily Intake (TDI) for PCDDs/PCDFs in June 1996. And the study team on risk assessment set by Environment Agency proposed 5 pg.TEQ/kg/d as a risk assessment reference value for PCDDs/PCDFs in December 1996. These figures are obtained by dividing No Observed Adverse Effect Level (NOAEL) value (1 ng.TEQ/kg/d) by uncertainty factors 100 and 200, respectively. Exposures of PCDDs/PCDFs to the human and health risk are discussed here.