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821.
Xiaoming Xu Jie Tang Zhaoyang Li Chang Liu Weizheng Han 《Mitigation and Adaptation Strategies for Global Change》2011,16(6):721-731
In this study, paddy fields in Jilin province which are flooded parcel of arable lands used for growing rice (Oryza sativa Linn.) were selected as the object. Long-term exploitation of paddy fields led to variations of soil organic carbon (SOC) and green
house gases (GHGs) emissions which might contribute to global warming. In order to calculate the amount of global warming
potentials (GWPs) of emissions from ricepaddies and find the correlations among rice yield, SOC storage and GWP, DeNitrification-DeComposition
(DNDC) model was used to simulate SOC densities and fluxes of main GHGs emitted from paddy fields. After verification, simulation
results were used to calculate SOC storages and 100-year GWPs from 1949 to 2009. Results indicated that SOC densities in depths
of 0–10 cm, 10–20 cm and 20–30 cm all kept increasing. Average methane (CH4) and nitrous oxide (N2O) fluxes were 278.55 kg carbon (kgC) ha−1 a−1 and 2.22 kg nitrogen (kgN) ha−1 a−1. The SOC storage (0–30 cm) had increased from 3.96 × 109kgC in 1949 to 47.85 × 109kgC in 2009. In addition, GWP emission was increasing exponentially in the past 61 years, from 0.16 × 106 Mg carbon dioxide equivalents (CO2-equivalents) to 66.36 × 106 Mg CO2-equivalents. Both SOC storage and GWP presented obviously linear relation to rice yields. Overall, the research suggested
that long-term rice yields could be used to estimate the SOC storage and GWP variations. 相似文献
822.
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824.
825.
以钦江青年水闸断面为研究对象,采用2001年~2009年的水质监测数据,计算了污染最重的氨氮、溶解氧和石油类3项污染因子的污染指数(Pi)及断面的综合污染指数(Pj)。通过分析得出,钦江青年水闸断面氨氮污染指数在2004年-2009年基本维持平缓,溶解氧和石油类污染指数在2001年-2006年期间上升幅度比较大,在2007年-2009年,逐步下降并且持续平缓。水质综合污染指数在2003年和2006年分别达到了5.440、4.940,断面水质属轻污染级别,2007年-2009年青年水闸断面的综合污染指数基本保持稳定(<4),河流水质的年际变化不大。 相似文献
826.
Zi Wu Zhi Li Li Zeng Ling Shao Hansong Tang Qing Yang Guoqian Chen 《Frontiers of Environmental Science & Engineering in China》2011,5(4):597-603
Distinct from the case with width-dominated shallow wetland flows, the longitudinal evolution of contaminant concentration
in the most-typical pattern of wetland as dominated by free-water-surface-effect is characterized by a multi-scale analysis
in the present study. An environmental dispersion model for the evolution of the mean concentration is deduced as an extension
of Taylor’s classical formulation by Mei’s multi-scale analysis. Corresponding environmental dispersivity is found identical
to that determined by the method of concentration moments. 相似文献
827.
Huan He Bo Tang Cheng Sun Shaogui Yang Weijuan Zheng Zichun Hua 《Frontiers of Environmental Science & Engineering in China》2011,5(3):409-416
High-affinity and specific monoclonal antibodies against cadmium-ethylene diamine tetraacetic acid (EDTA) complex have been
produced using the hybridoma technique. A hapten was synthesized and characterized by Fourier Transform Infrared Spectroscopy
(FT-IR) and UV-Vis. Competitive enzyme-linked immunosorbent assay (ELISA) for quantitative detection of cadmium in aqueous
sample was developed. The monoclonal antibody with high level of binding affinity for Cd-IEDTA-BSA and high specificity for
soluble Cd-EDTA complex showed less than 0.99% cross-reactivity with other 11 metals. The limit of detection was 0.10 μg·L−1, and the effective linear range was 10−1–103 μg·L−1. The intra- and inter-assay coefficient variations were 1.5%–6.3% and 3.2%–7.4%, respectively. The spike recovery in different
water samples were between 98.5% and 110.3%. The detection limit of this assay was well below the allowable concentration
of cadmium (3 μg·L−1), and the working range was wider than that of other methods which showed the range of 2.19–86.38 and 0–103 μg·L−1. The competitive ELISA established in this paper was sensitive and accurate in the screening of cadmium in aqueous samples.
The results will lay a solid foundation for construction of an immunoassay kit for cadmium. 相似文献
828.
Influence of influent on anaerobic ammonium oxidation in an Expanded Granular Sludge Bed-Biological Aerated Filter integrated system 总被引:1,自引:0,他引:1
Daijun Zhang Cui Bai Ting Tang Qing Yang 《Frontiers of Environmental Science & Engineering in China》2011,5(2):291-297
Shortcut nitrification-denitrification, anaerobic ammonium oxidation (ANAMMOX), and methanogenesis have been successfully
coupled in an Expanded Granular Sludge Bed-Biological Aerated Filter (EGSB-BAF) integrated system. As fed different synthetic
wastewater with chemical oxygen demand (COD) of 300–1200 mg·L−1 and NH4+-N of 30–120 mg·L−1 at the outer recycle ratio of 200%, the influence of influent on ANAMMOX in the integrated system was investigated in this
paper. The experimental results showed that higher COD concentration caused an increase in denitrification and methanogenesis
but a decrease in ANAMMOX; however, when an influent with the low concentration of COD was used, the opposite changes could
be observed. Higher influent NH4+-N concentration favored ANAMMOX when the COD concentration of influent was fixed. Therefore, low COD =NH4+-N ratio would decrease competition for nitrite between ANAMMOX and denitrification, which was favorable for reducing the
negative effect of organic COD on ANAMMOX. The good performance of the integrated system indicated that the bacterial community
of denitrification, ANAMMOX, and methanogenesis could be dynamically maintained in the sludge of EGSB reactor for a certain
range of influent. 相似文献
829.
锅炉灰渣综合利用就是利用灰渣烧结砖代替粘土实心砖,以资源的高效和循环利用,促进经济、社会的可持续发展。以宁安化工名锅炉有限公司锅炉灰渣。 相似文献
830.
Whether plant coexistence can reduce the impacts of lead (Pb) on crops in agroecosystems has not been well understood. We conducted a factorial experiment to investigate the effects of weeds coexisting with maize (Zea mays L.) on Pb accumulation in maize and soil microbes at two Pb levels (ambient and 300 mg/kg). Elevated Pb tended to increase the Pb concentration in maize and decreased soil microbial activity (indicated by the average well color development, AWCD), functional group diversity, as well as arbuscular mycorrhizal (AM) colonization and vesicle number of maize. Compared to the monoculture, weeds coexisting with maize reduced the Pb concentrations in the root, leaf, sheath and stem of maize at both seedling and mature stages. In maize-weed mixtures, soil microbial activity and functional group diversity tended to increase for both Pb treatments relative to the monoculture. Furthermore, principal component analysis revealed that the soil microbial community structure changed with the introduction of weeds. The highest Pb accumulation in weeds occurred for the elevated Pb treatment in a three species mixture. The results suggest that multiple plant species coexistence could reduce lead accumulation in crop plants and alleviate the negative impacts on soil microbes in polluted land, thereby highlighting the significance of plant diversity in agroecosystems. 相似文献