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BACKGROUND Problems associated with PBDEs/ PCBs/ PAHs and heavy metals mixed contaminated sites have received wide attention. To address the associated environmental concerns, innovative remediation techniques are urgently needed. RESULTS 5.0 mL L−1 peanut oil and 5.0 g L−1 tea saponin were found to be effective in extracting 94.6%, 97.1%, 95.1%, 83.5%, and 87.1% of PBDEs, PCBs, PAHs, Pb, and Ni, respectively, after two successive washing cycles. Cultivation of vetiver grass and addition of nutrients for 4 months further degraded 45.1%, 36.2%, and 40.2% of the residual PBDEs, PCBs and PAHs, respectively. Pb and Ni removal efficiencies by phytoextraction were 4.1% and 2.0%, respectively. The combined treatment partially restored the microbiological functions of washed soil, as indicated by a significant increase in the number, biomass C, N, and functioning diversity of soil microorganisms ( P < 0.05). After treatment, the residual organic pollutants and heavy metals mainly existed as very slowly desorbing fractions and residual fractions, as evaluated by Tenax extraction combined with a first-three-compartment model and sequential extraction. The secondary environmental risk of residual mixed pollutants in the remediated soil was limited. CONCLUSION The proposed combined cleanup strategy proved to be effective and environmentally friendly. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]