Partitioning variation of heavy metals in contaminated river sediment via bioleaching: effect of sulfur added to total solids ratio.
The aim of this study was to determine the effect of the ratio of sulfur added to total sediment solids (SA/TS) on the remobilization of heavy metals from contaminated river sediment by indigenous sulfur-oxidizing bacteria. Also, the difference in metal binding fractions before and after bioleaching was explored. It was found that sediment pH decreased at a significantly faster rate at higher SA/TS ratios (0.413 and 0.199) than at lower ones. Sulfate concentrations increased at a faster rate at these higher SA/TS ratios. At the lower SA/TS ratios, more acid must be produced and therefore it took more time for sulfur-oxidizing bacteria to lower the sediment pH. Remobilization efficiency of total extractable Pb and Cr was significantly higher at higher SA/TS ratios. After bioleaching, Mn-oxides became a stronger binding pool, and the percentage of Pb and Zn bound to Mn-oxides and Cr and Cu bound to organic matter increased with the decrease of SA/TS. Different heavy metals showed different binding behavior at the various SA/TS ratios.
Tsai
Li-Jyur
LJ
Department of Environmental Engineering and Science, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan.
Yu
Kuang-Chung
KC
Chen
Shu-Fen
SF
Kung
Pei-Yi
PY
Chang
Chia-Yuan
CY
Lin
Chao-Hsien
CH
D001419:Bacteria; D001682:Biological Availability; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D019216:Metals, Heavy / Q000032:analysis / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry* / Q000378:metabolism; D014871:Water Microbiology; D014873:Water Pollutants / Q000032:analysis*
D019216:Metals, Heavy; D014873:Water Pollutants; D013455:Sulfur