Abstract: Taking Brassica juncea as a hyperaccumulator, a pot experiment was conducted to study the effects of Bacillusme gaterium-Bacillus mucilaginosus mixed agent and Aspergillus niger 30177 fermentation liquor on the phytoremediation of Cd, Pb, and Zn-contaminated soil. The B. gaterium-B. mucilaginosus mixed agent not only promoted the growth of B. juncea, but also increased the soil Cd, Pb, and Zn uptake by the hyperaccumulator, with the phytoremediation  efficiency enhanced greatly. The enrichment amount of Cd, Pb and Zn in B. juncea on the soil added with soluble Cd, Pb and Zn increased by 118, 154 and 085 folds, while that on the soil added with Cd, Pb and Zn-contaminated sediment increased by 400, 064 and 065 folds, respectively, compared with the control. A. niger 30177 fermentation liquor increased the soil Cd, Pb, and Zn uptake by B. juncea. Comparing with the control, the enrichment amount of Cd, Pb and Zn in aboveground part of B. juncea on the soil added with soluble Cd, Pb and Zn increased by 8882%, 12904% and 1680%, while that on the soil added with Cd, Pb and Zn-contaminated sediment increased by 7895%, 11363% and 3385%, respectively. However, A. niger 30177 fermentation liquor decreased the B. juncea biomass greatly, having less effect in the enhancement of phytoremediation efficiency. The analysis of reversed-phase high performance liquid chromatography showed that the fermentation liquor of B. gaterium and B. mucilaginosus contained some organic acids such as oxalic acid and citric acid. These acids could dissolve the heavy metals to some degree, and accordingly, enhance the bioavailability of the metals.

Key words: phytoremediation, microbial promotion, soil contamination, cadmium, lead, zinc, yield, quality., partition rate of ¹⁵N, nitrogen fertilization with subsurface irrigation, broadcast fertilization, utilization rate of ¹⁵N, nitrogen fertilization with drip irrigation