An experimental study was carried out on the sorption of tetravalent ions Zr4+ and Hf4+ onto hydrous ferric oxide (HFO) and their fractionation behavior during colloid/solution interaction. The sorption of the isovale...An experimental study was carried out on the sorption of tetravalent ions Zr4+ and Hf4+ onto hydrous ferric oxide (HFO) and their fractionation behavior during colloid/solution interaction. The sorption of the isovalent ions Zr4+ and Hf4+ onto HFO is nonlinear, and they are fractionated during the sorption and co-precipitation processes: Zr4+ is more affinitive for HFO than Hf4+. At pH<6, the Zr/Hf ratios in solid phase decrease sharply with increasing pH values, but keep unchanged at pH>6. In both cases, the sorption/desorption or particle/water reaction can significantly fractionate Zr/Hf in the surface environment of the Earth.展开更多
Thirty-one congeners of polychlorinated naphthalenes (PCNs) and 21 congeners of polybrominated diphenylethers(PBDEs)in surface sediments at 5 stations and one mussel sample from Qingdao coastal waters were analyzed. T...Thirty-one congeners of polychlorinated naphthalenes (PCNs) and 21 congeners of polybrominated diphenylethers(PBDEs)in surface sediments at 5 stations and one mussel sample from Qingdao coastal waters were analyzed. The maximum contents occur at the station near the Haibo River mouth. The total PCNs contents are in the range of 212-1209 pg/g dw, dominated by tri-Cl CN. The total PBDEs contents are in the range of 117-5510 pg/g dw,dominated by tri- to hexa-BrBDEs. The local sources of PCNs are likely from combustion processes such as incinerations and coal burnings. The sources of PBDEs are molecular diffusion from the materials containing them. Except for the area near the river mouth where is affected by the sewage sludges, an important source of PCNs and PBDEs in this area is believed to be the atmospheric deposition. Mussels enrich PCNs and PBDEs relative to the sediments. The total TEQs of PCNs in mussels are lower than the total TEQs of PCBs.展开更多
The Aha Lake, as a seasonally oxygen-absent man-made reservoir, has been polluted by acidic mining drainage and domestic sewages for a long time, with iron, manganese and sulfate excessively enriched in water and sedi...The Aha Lake, as a seasonally oxygen-absent man-made reservoir, has been polluted by acidic mining drainage and domestic sewages for a long time, with iron, manganese and sulfate excessively enriched in water and sediment. By means of microbe counting, the analysis of trace metals in pore water and electronic acceptors for or-ganic matter decomposing, we have found that strong bio-geochemical remobilization of trace metals occurred near the water-sediment interface. The microbial reduction of iron, manganese and sulfate took place in different parts throughout the sediment core with the extend of iron reduc-tion lower than that of sulfate reduction, which happened in the surficial sediments and hampered the upward release of some trace metals to some extent. Some trace metals in pore water, due to the 揹ual releasing?effects caused by the re-duction of Fe3+ and Mn4+ at varying depth, show a tendency of being enriched excessively in the upper 10 cm of sediment. In this study, we discussed the microbiological mechanism of trace metals enrichment in surficial sediments and the envi-ronmental condition, with an attempt to realize the unsteady mobilization of trace metals and their potential harm to overlying lake water in the Aha Lake, Guiyang.展开更多
文摘An experimental study was carried out on the sorption of tetravalent ions Zr4+ and Hf4+ onto hydrous ferric oxide (HFO) and their fractionation behavior during colloid/solution interaction. The sorption of the isovalent ions Zr4+ and Hf4+ onto HFO is nonlinear, and they are fractionated during the sorption and co-precipitation processes: Zr4+ is more affinitive for HFO than Hf4+. At pH<6, the Zr/Hf ratios in solid phase decrease sharply with increasing pH values, but keep unchanged at pH>6. In both cases, the sorption/desorption or particle/water reaction can significantly fractionate Zr/Hf in the surface environment of the Earth.
文摘Thirty-one congeners of polychlorinated naphthalenes (PCNs) and 21 congeners of polybrominated diphenylethers(PBDEs)in surface sediments at 5 stations and one mussel sample from Qingdao coastal waters were analyzed. The maximum contents occur at the station near the Haibo River mouth. The total PCNs contents are in the range of 212-1209 pg/g dw, dominated by tri-Cl CN. The total PBDEs contents are in the range of 117-5510 pg/g dw,dominated by tri- to hexa-BrBDEs. The local sources of PCNs are likely from combustion processes such as incinerations and coal burnings. The sources of PBDEs are molecular diffusion from the materials containing them. Except for the area near the river mouth where is affected by the sewage sludges, an important source of PCNs and PBDEs in this area is believed to be the atmospheric deposition. Mussels enrich PCNs and PBDEs relative to the sediments. The total TEQs of PCNs in mussels are lower than the total TEQs of PCBs.
基金supported by the research project of the Chinese Academy of Sciences(KZCXZ-105).
文摘The Aha Lake, as a seasonally oxygen-absent man-made reservoir, has been polluted by acidic mining drainage and domestic sewages for a long time, with iron, manganese and sulfate excessively enriched in water and sediment. By means of microbe counting, the analysis of trace metals in pore water and electronic acceptors for or-ganic matter decomposing, we have found that strong bio-geochemical remobilization of trace metals occurred near the water-sediment interface. The microbial reduction of iron, manganese and sulfate took place in different parts throughout the sediment core with the extend of iron reduc-tion lower than that of sulfate reduction, which happened in the surficial sediments and hampered the upward release of some trace metals to some extent. Some trace metals in pore water, due to the 揹ual releasing?effects caused by the re-duction of Fe3+ and Mn4+ at varying depth, show a tendency of being enriched excessively in the upper 10 cm of sediment. In this study, we discussed the microbiological mechanism of trace metals enrichment in surficial sediments and the envi-ronmental condition, with an attempt to realize the unsteady mobilization of trace metals and their potential harm to overlying lake water in the Aha Lake, Guiyang.
