Long-Term Monitoring of Dioxin and Furan Level in Soil Around Medical Waste Incinerator

Abstract

The annual generation of solid waste is quite huge in China. For instance, approx. 157 million tons of municipal solid waste (MSW) and 2.04 billion tons of industrial solid waste (14.29 million tons of hazardous waste) were produced in 2009 (National Bureau of Statistics of China, 2010). These wastes would contaminate green land, drinking water and even air, ultimately threatening human health, so they must be treated in scientific methods. Waste treatment is a big challenge for every country. At present, the conventional disposal system according the hierarchy of methodologies includes recycle, compost, combustion and landfill. Combustion has noticeable advantages in volume and weight reduction, disinfection and short time cost, can also realize energy recovery by using waste to energy plants. Thermal treatment (pyrolysis and incineration) is the widely applied technology for waste treatment, for instance, accounting for 18.2% of MSW treatment in China and 11.9% in USA (2009). There are over 300 central incinerators for hazardous solid waste (HSW) in China (National Development and Reform Commission of China, 2003) and 93 municipal solid waste incinerators (National Bureau of Statistics of China, 2010). The present Chinese regulations prohibit the co-combustion of HSW and MSW (Ministry of Environment Protection, 2001). However, waste incineration is still a controversial issue among social and scientific communities due to its secondary pollution, especially after the observation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in incinerators (Olie et al., 1977). Waste incineration is thought a major source of PCDD/Fs in the environment. UNEP (UNEP Chemical, 2005) published the standardized toolkit for identification and quantification of dioxin and furan, including the emission factor of PCDD/Fs from combustion and incineration. Research (Gao et al., 2009; Ni et al., 2009) shows the emission factor of PCDD/Fs from medical waste incinerators (MWI) is nearly 63.3 μg I-TEQ/ton refuse into the atmosphere and 1.73 μg I-TEQ/ton from municipal solid waste incinerators (MSWI) in China, respectively. There are 135 dioxins and 175 furans, each with a different number and position of the chlorine atoms. 17 congeners of PCDD/Fs with 2,3,7,8 positions substituted by chorine are very toxic, which can induce a variety of adverse health problems, such as sarcomas, lymphomas and stomach cancer (Mitrou et al., 2001). These toxic pollutants can be formed by de novo synthesis and from precursor compounds (McKay, 2002), be emitted into the air through the stack, and transported to the ambient air,