title: [Effect of Soil and Dominant Plants on Mercury Speciation in Soil and Water System of Water-Level-Fluctuation Zone in the Three Gorges Area].
abstract: Plentiful plants in the water-level-fluctuation-zone (WLFZ) of Three Gorges Reservoir ( TGR) grow vigorously during the non-flooded period, especially the herbaceous ones. Then, the WLFZ is submerged gradually from the end of September. Soil-plant system that under a long time flooded condition may change the form of mercury, thus resulting in a secondary pollution of the water environment in TGR. To understand the characteristics of mercury species in soils and water after submerged, four kinds of typical plants from TGR were tested in the lab under submerged condition. The results indicated that the plants could promote the formation of soil methylmercury ( MeHg) , and had a significant effect on the different forms of mercury concentrations of the overlying water during inundation. Cynodon dactylon as the dominant species in WLFZ, because of its higher content of total mercury ( THg ) and methylmercury, the effect on MeHg and the other forms of mercury in the soil and the overlying water system was obvious. After 90 days, the soil MeHg level was the highest in Cynodon dactylon & soil & water treatment (B1) [(1,135.86 ± 113.84) ng · kg⁻¹]. It was approximately 2 times less than that of the soil MeHg in soil & water treatment (CK2) . The variation characteristics of total mercury (THg), reactive mercury (RHg) , dissolved mercury (DHg), total methylmercury (TMeHg) and dissolved methylmercury (DMeHg) of overlying water all showed a parabolic shape with a peak skewed to the left, and the peak was reached on the 30th day. Meanwhile, TMeHg, THg and DHg in B1 treatment were the highest, which were (2.88 ± 0.06), (40.29 · 2.42) and (35.51 · 3.77) ng · L⁻¹ respectively, and TMeHg and THg in the overlying water were mainly in the form of dissolved state. Therefore, it could be inferred that the water consumption of the Three Gorges reservoir would increase the mercury pollution load of the reservoir.
authors.forename: Li
authors.initials: L
authors.lastname: Liang
authors.forename: Yong-min
authors.initials: YM
authors.lastname: Wang
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhang
authors.forename: Ya-wei
authors.initials: YW
authors.lastname: Yu
authors.forename: Si-wei
authors.initials: SW
authors.lastname: An
authors.forename: Ding-yong
authors.initials: DY
authors.lastname: Wang
mesh_terms: D002681:China; D004784:Environmental Monitoring; D055868:Floods; D008628:Mercury / Q000737:chemistry*; D008767:Methylmercury Compounds / Q000737:chemistry; D010944:Plants; D045483:Rivers / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D008767:Methylmercury Compounds; D012987:Soil; D014874:Water Pollutants, Chemical; D014867:Water; D008628:Mercury