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151.
Accumulation and distribution of polycyclic aromatic hydrocarbons in rice (Oryza sativa) 总被引:6,自引:0,他引:6
Tao S Jiao XC Chen SH Liu WX Coveney RM Zhu LZ Luo YM 《Environmental pollution (Barking, Essex : 1987)》2006,140(3):406-415
Various tissues of rice plants were sampled from a PAH contaminated site in Tianjin, China at different growth stages of the ripening period and analyzed for PAHs. PAHs were much higher in roots than in the exposed tissues. Grains and internodes accumulated much smaller amounts of PAHs than leaves, hulls or ear axes. No specific gradient trends along roots, stem, ear axes, and grains were observed, suggesting that systematic translocation among them is unlikely. Over the ripening period, PAH concentrations were increased in rice roots and decreased in most above-ground tissues. Significant correlations between PAH and lipid contents can only be observed during full mature stage. The spectra of individual PAH compounds in rice organs including roots were similar to those in air, rather than those in soil. There was also a significant correlation between bioconcentration factor (BCF, plant over air) and octanol/air partitioning coefficient (Koa). 相似文献
152.
甲烷被认为是仅次于CO_2的具有温室效应的气体.在农业生态系统中,稻田是甲烷的主要来源.讨论稻田甲烷排放量、排放机制,提出减少稻田甲烷排放的控制措施,对控制稻田生态效益提供依据.此外,本文结合稻田生态效益提高途径进行科学认识. 相似文献
153.
稻壳综合利用的最佳途径 总被引:1,自引:0,他引:1
简述了稻壳综合利用现状,介绍了稻壳成型工艺及铁水保温及转炉炼钢方面的应用,并比较了稻壳块同其他保温剂性能的优劣,实践证明,成型后的稻壳块用于铁水保温及转炉冶炼过程中的喷溅和溢渣控制技术上,所产生的经济和社会效益是巨大的,也是其它稻壳综合利用途径所无法比拟的,钢铁冶金工业,是稻壳综合利用的最佳途径。 相似文献
154.
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156.
接枝羧基淀粉去除水体中有毒重金属离子的研究 总被引:28,自引:1,他引:28
以可溶性淀粉为基体,经环氧氯丙烷交联,制备了交联淀粉。以Fe^2+-H2O为引发剂将丙烯腈单体接枝到交联淀粉上,再经过皂化制得水不溶性接枝羧基淀粉聚合物(ISC)。通过红外光谱表征结构。用静态法和动态法研究ISC去除水体中Cd^2+、Pb^2+、Cu^2+、Hg^2+、Cr2+等离子的效果及PH值对去除效果的影响,并对其作用机理进行探讨。 相似文献
157.
Synthesis and application of lignin-based copolymer LSAA on controlling
non-point source pollution resulted from surface runoff 总被引:2,自引:0,他引:2
LIU Chen WU Guangxi MU Huanzhen YUAN Zonghuan TANG Lianyi LIN Xiangwei 《环境科学学报(英文版)》2008,20(7):820-826
In this article,alkali lignin separated from paper pulp waste was grafted into a novel copolymer LSAA (a copolymer of lignin,starch, acrylamide,and acrylic acid).Its practical application effect and environmental safety were studied.The results of field simulation experiment indicated that the application of LSAA significantly affected the output of the runoff and pollutants.The runoff quantity was decreased by 16.67%-47.00%and the loads of total suspended solids (TSS),chemical oxygen demand (COD),total ... 相似文献
158.
Effect of water-driven changes in rice rhizosphere on Cd lability in three soils with different pH 总被引:2,自引:0,他引:2
Jinjin Wang Dongqin Li Qin Lu Yulong Zhang Huijuan Xu Xueli Wang Yongtao Li 《环境科学学报(英文版)》2020,32(1):82-92
Pot experiments were conducted to evaluate the effect of water management, namely continuous flooding (CF), intermittent flooding (IF) and non-flooding (NF), on Cd phytoavailaility in three paddy soils that differed in pH and in Cd concentrations. Diffusive gradients in thin films (DGT) technique was employed to monitor soil labile Cd and Fe concentrations simultaneously at three growth stages (tillering, heading and mature stage) of rice. The Cd phytoavailability were generally in the order of NF?>?IF?>?CF, and higher rice Cd (over permitted level, 0.2?mg/kg) were only found in neutral and acidic soils under NF conditions. DGT measured soil labile Cd rather than total Cd was the most reliable predictor for Cd accumulation in rice. CF enhanced the formation of root plaques, which related to oxidation of large quantities of available Fe on root surfaces due to the O2 secretion of rice root. The Cd concentration in root plaques shared the same trend with DGT-Cd. Generally, root plaques would inhibit Cd uptake by rice under CF conditions, while under IF and NF conditions, root plaques act as a temporarily store of Cd, and soil labile Cd is the key factor that controls the transfer of Cd from soil to rice. The results of principle component analysis revealed that water management had the greatest effect on soil Cd lability and rice Cd in acidic soil. Thus, it is important to consider the availability of Cd and soil pH when assessing current agricultural practices of contaminated soil in China. 相似文献
159.
Wenjun Dong Jia Guo Lijun Xu Zhifeng Song Jun Zhang Ao Tang Xijuan Zhang Chunxu Leng Youhong Liu Lianmin Wang Lizhi Wang Yang Yu Zhongliang Yang Yilei Yu Ying Meng Yongcai Lai 《环境科学学报(英文版)》2018,30(2):289-297
Water regime and nitrogen (N) fertilizer are two important factors impacting greenhouse gases (GHG) emission from paddy field, whereas their effects have not been well studied in cold region. In this study, we conducted a two-year field experiment to study the impacts of water regime and N fertilizer on rice yields and GHG emissions in Harbin, China, a cold region located in high latitudes. Our results showed that intermittent irrigation significantly decreased methane (CH4) emission compared with continuous flooding, however, the decrement was far lower than the global average level. The N2O emissions were very small when flooded but peaked at the beginning of the disappearance of floodwater. The N fertilizer treatments increased CH4 emissions at low level (75kgN/ha). But both CH4 and N2O emissions were uninfluenced at the levels of 150kgN/ha and 225kgN/ha. Rice yields increased under intermittent irrigation and were highest at the level of 150kgN/ha. From our results, we recommended that the intermittent irrigation and 150kgN/ha as the ideal water regime-nitrogen fertilizer incorporation for this area to achieve low GHG emissions without impacting rice yields. 相似文献
160.
Effects of soil properties on production and bioaccumulation of methylmercury in rice paddies at a mercury mining area, China 总被引:2,自引:0,他引:2
Rice paddy soil is recognized as the hotspot of mercury(Hg) methylation, which is mainly a biotic process mediated by many abiotic factors. In this study, effects of key soil properties on the production and bioaccumulation of Hg and methylmercury(MeHg) in Hg-contaminated rice paddies were investigated. Rice and soil samples were collected from the active Hg smelting site and abandoned Hg mining sites(a total of 124 paddy fields) in the Wanshan Mercury Mine, China. Total Hg(THg) and MeHg in soils and rice grains, together with sulfur(S),selenium(Se), organic matter(OM), nitrogen(N), phosphorus(P), mineral compositions(e.g., SiO_2, Al_2O_3 and Fe_2O_3) and pH in soils were quantified. The results showed that long-term Hg mining activities had resulted in THg and MeHg contaminations in soil-rice system. The newly-deposited atmospheric Hg was more readily methylated relative to the native Hg already in soils, which could be responsible for the elevated MeHg levels in soils and rice grains around the active artificial Hg smelting site. The MeHg concentrations in soils and rice grains showed a significantly negative relationship with soil N/Hg, S/Hg and OM/Hg ratio possibly due to the formation of low-bioavailability Hg–S(N)–OM complexes in rhizosphere. The Hg–Se antagonism undoubtedly occurred in soil-rice system, while its role in bioaccumulation of MeHg in the MeHg-contaminated rice paddies was minor. However, other soil properties showed less influence on the production and bioaccumulation of MeHg in rice paddies located at the Wanshan Mercury Mine zone. 相似文献