Levels, profiles and source identification of PCDD/Fs in farmland soils of Guiyu, China

The present study finished the first comprehensive survey of polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) in farmland soils of Guiyu, China. Guiyu was a major electronic wastes (EWs) dismantling area, but primitive and crude EWs disposal manner had led to severe PCDD/Fs pollution there. Twenty-three farmland soil samples covering the entire Guiyu region were analyzed. Toxic equivalent quantities (I-TEQs) of soils in EWs disposal areas were 5.7-57 pg TEQ g−1, and the total concentrations of tetra- to octa-homologues were 2816-17 738 pg g−1. The SL district was a heavily contaminated area, and the neighboring SMP town was influenced by Guiyu. EWs disposal might be the source of PCDD/Fs. The homologue profiles were of three types, representing different disposal manner of EWs. Tetrachlorodibenzo-p-dioxins (TCDDs) and octachlorodibenzo-p-dioxin (OCDD) could be used as indicators for source identification, open thermal disposal of EWs was inclined to lead to formation of TCDDs, OCDD was a product of non-thermal processes.

► The first comprehensive survey of PCDD/Fs in farmland soils of Guiyu, China. ► The different disposal manner of e-wastes appeared different homologue profiles. ► TCDD was indicator for open thermal disposal of e-wastes. ► OCDD was indicator for non-thermal process. ► The disposal of e-wastes was the source of PCDD/Fs in Guiyu.