作者机构：
[黄运湘; 王翠红; 胡瑞芝; 张杨珠] College of Resource and Environment Science, Hunan Agricultural University, Changsha 410128, China;[邹应斌] College of Agronomy, Hunan Agricultural University, Changsha 410128, China;[李法云] College of Environment and Life Science, Liaoning University, Shenyang 110036, China;[冯跃华] College of Resource and Environment Science, Hunan Agricultural University, Changsha 410128, China, College of Agronomy, Hunan Agricultural University, Changsha 410128, China
通讯机构：
[Feng, Y.] C;College of Resource and Environment Science, , Changsha 410128, China
摘要：
Through a batch experiment, the mobility and speciation of heavy metals(Cd, Cu, Zn) in two acidic forest soils from Hunan Province were studied. The results showed that the release and potential active speciation of Cd, Cu, and Zn in the tested contaminated red soil(CRS) and yellow red soil(CYRS) increased significantly with pH decreasing and ion concentrations increasing of simulated acid rain, and these effects were mainly decided by the pH value of simulated acid rain. Cd had the highest potential risk on the environment compared with Cu and Zn. Cd existed mainly in exchangeable form in residual CRS and CYRS, Cu in organically bound and Mn-oxide occluded forms, and Zn in mineral forms due to the high background values.
摘要：
Laboratory experiments about the dissipation, adsorption and translocation in four paddy topsoils were conducted in this paper. From the results it can be concluded as follows: the dissipation rate of clomazone differed greatly in different paddy soil derived from different parent materials. The half-lives for clomazone degradation in paddy soils ranged from 5.7 to 22.0 d. The order of clomazone dissipation rate was reddish yellow paddy soil ＞alluvial sandy paddy soil ＞ yellow clayey paddy soil ＞ purple sandy paddy soil. Clomazone sorption quantity was significantly correlated with organic carbon ( R2 = 0.62) and clay content ( R2 = 0.67) in the tested paddy soils.Positive correlation was found between apparent Kd value and cation exchange content(CEC). The consequences for the adsorption of different soils were purple sandy paddy soil ＞ yellow clayey paddy soil ＞ reddish yellow paddy soil ＞ alluvial sandy paddy soil. Under the simulated rainfall of 200 mm through four different unsaturated soil lysimeters over 24 h, clomazone was readily to be leached into lower surface soil and there was about 2.6%-4.2%of applied clomazone leached out of 20 cm cultivated soil layer. Translocation experiments showed that the order of clomazone leaching ability was: alluvial sandy paddy soil ＞ reddish yellow paddy soil ＞ yellow clayey paddy soil ＞purple sandy paddy soil. Simple regression results manifested that factors like CEC, organic carbon, clay, and adsorption rate constant had been negatively correlated with the percentage of clomazone loss from soil lysimeters.
摘要：
Background. Methyl tertiary butyl ether (MTBE) is the second most highly produced industrial chemical in the US and a frequent groundwater pollutant. At the same time, MTBE is quite persistent to biotic and abiotic decomposition. The goal of this study was to find plant species that could degrade MTBE and might be used in phytoremediation. Methods. Excised roots and leaves (0.3 g) from more than 24 Danish plant species out of 15 families were kept in glass vessels with 25 ml spiked aqueous solution for 2 to 4 days. MTBE concentrations were 1 to 5 mg/L. Samples were taken directly from the solution with a needle and injected to a purge and trap unit. MTBE and the main metabolite, TBA, were measured by GC/FID. Results and Discussion. Solutions with roots of poplar (Populus robusta) and a willow hybrid (Salix viminalis x schwerinii) produced TBA in trace amounts, probably stemming from bacteria. Significant MTBE reduction (> 10%) was not observed in any of the tests. Leaves from none of the species (trees, grasses and herbs) reduced the concentration of MTBE in the solution and no TBA, nor any other known metabolite of MTBE, was detected. Conclusion. It was not possible to find plants capable of efficiently degrading MTBE. This gives rise to the conclusion that plants probably cannot degrade MTBE at all, or only very slowly. Recommendations and Outlook. For phytoremediation projects, this has, as consequence, that the volatilization by plants (except with genetically engineered plants) is the only relevant removal process for MTBE. For risk assessment of MTBE, degradation by the plant empire is not a relevant sink process.
作者机构：
[廖继佩; 张杨珠; 冯跃华; 黄运湘] College of Rsrc./Environment Sci., Hunan Agricultural University, Changsha 410128, China;[李法云] College of Environmental/Life Sci., Liaoning University, Shengyang 110036, China
通讯机构：
[Liao, J.] C;College of Rsrc./Environment Sci., , Changsha 410128, China
作者机构：
[黄昌勇; 郭朝晖] College of Environment/Resource Sci., Zhejiang University, Hangzhou 310029, China;[廖柏寒] College of Nat. Rsrc./Environ. Sci., Hunan Agricultural University, Changsha 410128, China
通讯机构：
[Guo, Z.] C;College of Environment/Resource Sci., , Hangzhou 310029, China
