Abstract: In order to realize the remediation and treatment of composite heavy metal pollution of copper ore dressing and smelting slag,this study focuses on a typical copper smelting slag site in Sichuan,China. Sulfate-reducing bacteria (SRB) were employed as the bioremediation agent to investigate their growth characteristics,the variation of heavy metal ions in solution and the remediation effects. The results demonstrate that SRB can proliferate rapidly during the remediation process,making them suitable for the treatment of composite heavy metal pollution. Due to the significant activity differences among heavy metals such as iron,zinc,copper and lead,their stabilization effects also vary considerably. Within 30 days,the optimal inoculation rates for the four heavy metals of Cu、Pb、Zn、Fe were 5%,10%,15%,and 15%,respectively,with the bioavailability reduction rates of 72. 36%,98. 37%,43. 01% and 79. 31%. As the stabilization period increased,the concentration of heavy metal ions in the solution initially increased and then decreased,but this did not affect the remediation effect. Therefore,SRB can simultaneously remediate multiple heavy metals,effectively addressing the composite heavy metal pollution of iron,zinc,copper,and lead in the typical copper smelting slag in Sichuan.

Key words: copper mining slag,sulfate-reducing bacteria,contamination by complex heavy metals,bioavailability