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961.
Occurrence of arsenic in brown rice and its relationship to soil properties from Hainan Island, China 总被引:3,自引:0,他引:3
Fu Y Chen M Bi X He Y Ren L Xiang W Qiao S Yan S Li Z Ma Z 《Environmental pollution (Barking, Essex : 1987)》2011,159(7):1757-1762
The acquaintance of arsenic concentrations in rice grain is vital in risk assessment. In this study, we determined the concentration of arsenic in 282 brown rice grains sampled from Hainan Island, China, and discussed its possible relationships to the considered soil properties. Arsenic concentrations in the rice grain from Hainan Island varied from 5 to 309 μg/kg, with a mean (92 μg/kg) lower than most published data from other countries/regions and the maximum contaminant level (MCL) for Asi in rice. The result of correlation analysis between grain and soil properties showed that grain As concentrations correlated significantly to soil arsenic speciation, organic matter and soil P contents and could be best predicted by humic acid bound and Fe-Mn oxides bound As fractions. Grain arsenic rises steeply at soil As concentrations lower than 3.6 mg/kg and gently at higher concentrations. 相似文献
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964.
Luo SL Chen L Chen JL Xiao X Xu TY Wan Y Rao C Liu CB Liu YT Lai C Zeng GM 《Chemosphere》2011,85(7):1130-1138
This study investigates the heavy metal-resistant bacterial endophytes of Cd-hyperaccumulator Solanum nigrum L. grown on a mine tailing by using cultivation-dependent technique. Thirty Cd-tolerant bacterial endophytes were isolated from roots, stems, and leaves of S. nigrum L. and classified by amplified ribosomal DNA-restriction analysis into 18 different types. Phylogenetic analysis based on 16S rDNA sequences showed that these isolates belonged to four groups: Actinobacteria (43%), Proteobacteria (23%), Bacteroidetes (27%) and Firmicutes (7%). All the isolates were then characterized for their plant growth promoting traits as well as their resistances to different heavy metals; and the actual plant growth promotion and colonization ability were also assessed. Four isolates were re-introduced into S. nigrum L. under Cd stress and resulted in Cd phytotoxicity decrease, as dry weights of roots increased from 55% to 143% and dry weights of above-ground from 64% to 100% compared to the uninoculated ones. The total Cd accumulation of inoculated plants increased from 66% to 135% (roots) and from 22% to 64% (above-ground) compared to the uninoculated ones. Our research suggests that bacterial endophytes are a most promising resource and may be the excellent candidates of bio-inoculants for enhancing the phytoremediation efficiency. 相似文献
965.
966.
将平板微滤膜与A2/O工艺结合构建了A2/O-MBR中试系统,探讨了中试系统处理印染废水的效果及稳定性。结果表明,水解酸化可提高印染废水的可生化性,对COD平均去除率达到了43%。系统处理效果稳定,在最佳工况下COD、NH3-H和TN的去除率分别为88%、98%和80%。 相似文献
967.
O3氧化工艺处理黄连素制药废水研究 总被引:1,自引:0,他引:1
采用臭氧(O3)氧化法处理含高浓度黄连素和COD的制药废水,探讨了废水初始pH、O3投加量及初始黄连素浓度等因素对O3氧化过程的影响,确定了O3氧化技术处理黄连素制药废水的最佳操作条件。结果表明,O3能够有效分解废水中的黄连素,降低其COD浓度;黄连素浓度为700mg/L、COD为3500mg/L、pH为0.88的废水,进气O3浓度为14.05mg/(L·min),处理时间为180rain(即投加量为2529mg/L)时,黄连素和COD的降解率分别可达77.46%和41.28%,BOD,/COD比(B/C比)从0.06提高到0.34,增加了4.7倍;随着废水中初始黄连素浓度的升高,废水COD降解率逐渐降低。O3氧化法是一种有效的黄连素制药废水预处理技术,可以大大提高废水的可生化性。 相似文献
968.
Ground-level ozone in the Pearl River Delta and the roles of VOC and NO(x) in its production 总被引:3,自引:0,他引:3
Shao M Zhang Y Zeng L Tang X Zhang J Zhong L Wang B 《Journal of environmental management》2009,90(1):512-518
In many regions of China, very rapid economic growth has been accompanied by air pollution caused by vehicle emissions. In one of these regions, the Pearl River Delta, the variations of ground-level ozone and its precursors were investigated. Overall, the ambient concentrations of NO(2) increased quickly between 1995 and 1996, but then slightly decreased due to stringent nitrogen oxide (NO(x)) emission controls. Nonetheless, ambient NO(2) levels in the Pearl River Delta remained high. The regional average concentrations of volatile organic compounds (VOCs) were 290 ppbC in summer and 190 ppbC in autumn. Local emissions and long-distance transportation of pollutants play important roles in the regional distribution of VOCs. Ambient O(3) production is significant in urban areas and also downwind of cities. The relative incremental reactivities (RIRs), determined by an observation-based model, showed that ground-level ozone formation in the Guangzhou urban area is generally limited by the concentrations of VOCs, but there are also measurable impacts of NO(x). 相似文献
969.
970.
中国是世界上残障者最多的国家,其中肢残者达2,412万人,肢残者服装指专为肢体某部位出现运动障碍导致着装困难的残障者设计的服装,而由于各种原因造成国内市场普通成衣远不能满足他们对服装的特殊需求。论文在调研、总结、分析了国内外发展现状的基础上,以人为本,对肢残者服装的功能性、合体性、舒适性及美观性进行了探讨,提出了肢残者服装今后研发的对策和建议,为肢残服装的系统开发研究提供了参考。 相似文献