Small-scale waste incinerators in rural China: Potential risks of dioxin and polychlorinated naphthalene emissions

Rapid development has led to a tremendous increase in the volume of solid waste produced in rural China. The annual amount of solid waste produced from Chinese rural areas is approximately 110 million tons. Many small-scale solid waste incinerators have been built in Chinese rural areas. It was speculated that the emissions and potential risks of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs, commonly known as dioxins) and polychlorinated naphthalenes (PCNs) from these incinerators could be serious. A preliminary case investigation on PCDD/F and PCN emissions from a small-scale waste incinerator was performed. The stack gas samples were collected using auto isokinetic sampling techniques and PCDD/F and PCN congeners were identified and quantified by high resolution gas chromatography combined with high resolution mass spectrometry. Concentrations and toxic equivalents of PCDD/Fs emitted from the small-scale waste incinerator were 153 ng m −3 and 5.6 ng TEQ m −3 , respectively, which was much higher than the regulatory level for municipal solid waste incinerators permitted in China and the European Union Directive. PCNs have similar toxicological effects with PCDD/Fs, and the relative potency factors (RPFs) of some PCN congeners (dioxin-like PCNs) to 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD) were previously proposed to evaluate the dioxin-like toxicity of PCNs. The mass concentrations of PCNs and dioxin-like PCNs from the small-scale solid incinerator were 2927 ng m −3 and 1137 ng m −3 , much higher than that of dioxins. However, much less attention has been paid to the small-scale incinerators compared with municipal solid waste incinerators. Here, we proposed that there should be a growing need to focus on the emissions and potential risks of dioxins and dioxin-like pollutants from these small-scale waste incinerators in rural China.