Occurrence, distribution and annual emissions of chlorinated paraffins in hazardous byproducts from municipal solid waste incineration plants in South China

Nowadays incineration technology has become the most mainstream way for the disposal of municipal wastes. Short chain chlorinated paraffins (SCCPs) and medium chain chlorinated paraffins (MCCPs) are currently classified as new persistent organic pollutants (POPs) and candidate POPs under the Stockholm Convention, respectively. However, the occurrence and contamination characteristics of these main hazardous byproducts (e.g., leachate, fly ash, and bottom ash) from municipal solid waste incineration (MSWI) plants have remained unknown. This study focused on the SCCPs and MCCPs (defined as CPs) contamination and their annual emissions from leachate, fly ash, and bottom ash among three typical MSWI plants in Shenzhen, South China. Compared to the dissolved phase of the leachate, higher concentrations of CPs were detected in the adsorbed phase. The total concentrations of CPs ranged from lower method detection limits (1 in leachate (i.e., adsorbed phase) and bottom ash, while the opposite results were found in fly ash. The dominant SCCP congener groups were C10Cl6-7 in leachate and fly ash, and C13Cl6-7 in bottom ash. The dominant MCCP congener groups were C14Cl7-8 in leachate, fly ash and bottom ash samples. Principal component analysis (PCA) revealed the dominant CPs in fly ash were obviously different from those in leachate and bottom ash. Estimated total annual emissions of CPs from the three main hazardous byproducts generated from typical MSWI plants were estimated between 66.2 and 7510 kg/y and bottom ash contributed the most to the CP emissions. Overall, this study is the first report on CP contamination in hazardous byproducts from MSWI plants, and can provide basic data support for CP contamination control.