Effects of naturally recovered vegetation on chemical speciation of Mn in goldtracesmining wasteland, northeastern China.

Four vegetation types of typical goldmining wasteland were selected as the study subjects in Rouge Ditch of Mohe County in Daxingan Mountain, northeastern China. By applying BCR sequential extraction method, the effects of different vegetations on four chemical speciations of soil Mn were studied. The results showed that average contents of soil EXMn in Carex rhynchophysaIris ensata community(CR),Salix hsinganicaBetula platyphylla community(SH), Larix gmelinii community(LG), and Pinus sylvestris community(PS) were about 36.25%, 36.63%, 31.04% and 43.39% of the total content; average contents of REDMn took up 30.71%, 32.98%, 36.80% and 27.28% of the total; average contents of OXIMn took up 9.07%, 7.10%, 8.30% and 7.13% of the total; while average contents of RESMn accounted for 23.97%, 23.28%, 23.86% and 22;20% of the total. According to factoranalysis, CR was effective in immobilizing recalcitrant Mn and accumulated high quantity of EXMn; SH preserved few recalcitrant Mn and consumed large amount of EXMn; PS accumulated the largest amount of EXMn and proned to activize the recalcitrant Mn; LG consumed the largest share of EXMn and maintained a weak ability in activizing recalcitrant Mn. These results would provide reference for plant selection in vegetationrestoration process of goldmining wasteland.