Fig 1.
Map showing the locations of studied area of Dabaoshan Mine.
(● represented the sample sites; S0 was tailings impoundment; the S1 to S11 located in the Hengshi River affected by AMD; C1 to C3 were control sites located in the tributaries).
Table 1.
Adapted 7-steps sequential extractions sequences developed for this study.
Fig 2.
The variation of heavy metals concentration in Hengshi River.
Fig 3.
Activity of Fe3+ relative to pH (Solubility lines are as follows: goethite (log aFe3+ = 1.4-3pH), ferrihydrite (logaFe3+ = 4.3-3pH), and schwertmannite (log aFe3+ = 2.83–2.6pH), jarosite (log aFe3+ = -2.5–1.67 pH)).
Table 2.
Percentage of iron removed from synthetic minerals in each step of adapted 7-steps sequential extractions.
Fig 4.
SEM images of sediment samples before extraction (Sh: schwertmannite; Jt: jarosite; Gt: goethite; Fh: ferrihydrite; Gp: gypsum; (The scale of all figures is the same)).
Fig 5.
Sequential extractions of sediment samples from sampling sites (S0-S11).
Fig 6.
DXRD and semi-quantitative XRD patterns of sediment samples.
((a) and (b) DXRD patterns refer to samples S0 and S1; (c) and (d) refer to the mixture of NaCl with Sh and Fh; (e) and (f): Semi-quantitative XRD patterns of samples S7 and S8; the Sh: schwertmannite; Fh: Ferrihydrite).
Fig 7.
The content of heavy metals in the precipitates (A triplicate analysis was performed and the relative standard deviations were below 5%).
Fig 8.
Comparison of heavy metals contents in each extract phase of sample S7 (A triplicate analysis was performed and the relative standard deviations were below 5%).
Table 3.
Correlation coefficients calculated for the elements in the sediment samples.