Combining nontarget and target analysis to determine organic pollutants in secondary copper and aluminum smelter fly ash.

Abstract

Understanding secondary copper (Cu) smelter (SCS) and secondary aluminum (Al) smelter (SAS) fly ash compositions is critical for appropriate waste management and environmental risk control. Employing comprehensive two-dimensional gas chromatography with high resolution time-of-flight mass spectrometry combining nontarget analysis, the method detected 572, 899, and 612 organic compounds in dryer-derived SCS fly ash, blower-derived SCS fly ash, and SAS fly ash, respectively. Specifically, nontarget screening detected chlorinated and brominated organic contaminants encompassing polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and brominated aliphatic/aromatic compounds. Guided by nontarget results, PCDD/Fs and dioxin-like PCBs were observed by target analysis employing high resolution gas chromatography-high resolution mass spectrometry, demonstrating the toxic equivalent concentrations (μg/kg): PCDD/Fs - 19.280 (Cu dryer), 2.958 (Cu blower), 6.538 (Al); dioxin-like PCBs - 0.377 (Cu dryer), 0.276 (Cu blower), 0.130 (Al). In addition, higher chlorination degrees and PCDD/Fs and PCBs concentrations were detected in SCS fly ash relative to SAS fly ash, potentially attributable to distinct catalytic properties between Cu and Al.

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