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871.
长三角地区碳排放效率时空特征及影响因素分析 总被引:2,自引:0,他引:2
长三角区域一体化发展战略上升为国家战略,要求建立区域间协调机制,引导低碳产业,弥补绿色发展的短板。掌握长三角地区碳排放效率时空特征及其影响因素,对长三角地区低碳高效发展及顺利实现碳减排目标具有重要的现实意义。基于考虑非期望产出的SBM-DEA模型与窗口分析相结合的方法,测算碳排放效率,利用传统统计分析与空间分析相结合的方法,分析了1995~2017年长三角地区碳排放效率时空特征,并考虑空间因素,构建空间杜宾面板模型分析其影响因素。结果表明:(1)1995~2017年碳排放效率总体呈波动变化趋势。2017年,上海、苏州和无锡的碳排放效率为1。碳排放效率绝对差异与相对差异呈波动变化,且变化趋势基本一致。碳排放效率存在不均衡现象。(2)碳排放效率区域差异明显,2005年后,空间格局变化不大,上海、苏州和无锡形成了碳排放效率高值区。碳排放效率重心主要分布在南京市,总体向西北移动。(3)空间杜宾面板模型结果表明:提高技术水平是改变碳排放效率的重要途径。城镇化和空间因素对碳排放效率具有明显的正向作用;外商投资、单位GDP能耗和生态环境对碳排放效率具有明显的负向作用。 相似文献
872.
南水北调中线工程水源地的土壤可蚀性特征 总被引:1,自引:0,他引:1
选定南水北调中线工程水源地丹江口水库区这一国家水土流失重点治理区域为研究地点,对该地的土壤可蚀性特征进行了研究。在研究区不同土地覆盖类型里采取表层(20 cm)土壤样品,室内分析样品土壤的质地和有机质含量,利用EPIC模型及实验室分析的土壤质地和有机质数据计算样品土壤可蚀性K值。在ARCGIS里,利用Ordinary Kriging插值方法生成研究区K值分布图。然后按一定标准将K值进行分级,得出不同K等级值的空间分布及面积。结果表明:研究区K的均值为0034 8( t·hm2·h)/(hm2·MJ·mm),主要为中可蚀性土壤(面积占91.71%)。东部(主要是耕地)土壤K值高于西部(主要是林地),是侵蚀治理的重点地区。研究结果可为库区水土流失定量遥感监测提供基础资料,对库区的土壤侵蚀治理有一定的参考作用 相似文献
873.
Yuanchen Chen Guofeng Shen Shu Su Huizhong Shen Ye Huang Tongchao Li Wei Li Yanyan Zhang Yan Lu Han Chen Chunli Yang Nan Lin Ying Zhu Xiaofang Fu Wenxin Liu Xilong Wang Shu Tao 《Environmental science and pollution research international》2014,21(19):11521-11530
Smoked meat is widely consumed in many areas, particularly in rural southwest China. High concentrations of polycyclic aromatic hydrocarbons (PAHs) in smoked meat could lead to adverse dietary exposure and health risks. In this study, 27 parent PAHs (pPAHs), 12 nitrated PAHs (nPAHs), and 4 oxygenated PAHs (oPAHs) were measured in coal- and wood-smoked meats. The median concentrations of pPAHs, nPAHs, and oPAHs were as high as 1.66?×?103, 4.29, and 20.5 ng/g in the coal-smoked meat and 2.54?×?103, 7.32, and 9.26 ng/g in the wood-smoked meat, respectively. Based on the relative potency factors of individual PAHs, the calculated toxic equivalent (TEQ) values of all pPAHs were 22.1 and 75.1 ng TEQ/g for the wood- and coal-smoked meats, respectively. The highest concentrations of PAHs can be found in the surface layer of skin and decrease exponentially with depth. Surface PAH concentrations correlated with concentrations of PAHs in household air and with the concentration in emission exhaust. Migration of PAHs from surface to interior portions of meat is faster in lean than in fat or skin, and oPAHs and pPAHs can penetrate deeper than pPAHs. The penetration ability of PAHs is negatively correlated with the molecular weight. 相似文献
874.
利用干燥空气替换亚临界水作为蒸发壁流体,对传统蒸发壁超临界水氧化反应器进行了改进,即将干燥空气用作污染物超临界水氧化反应氧化剂的同时,又作为该超临界水氧化反应体系的密封介质,避免其与反应器内壁的直接接触,以改善超临界水氧化反应器的耐腐蚀性能。通过对采用城市活性污泥和异丙醇配制的高浓度难降解污染物悬浮液进行超临界水氧化处理后,发现反应器内衬陶瓷管在实验前后无论是外观形貌,还是结构组成均未发生明显变化;处理后液体COD降至80 mg/L以下,去除率达到99.6%以上,固体残渣量约为污染物总量的1%,且体系运行过程中压力和温度控制准确,可操作性强。进一步验证了将干燥空气作为超临界水氧化体系的密封介质具有可行性,同时表明,该气封壁超临界水氧化反应系统可用于高浓度难降解有机污染物的环境处理。 相似文献
875.
生物墙对地下水中六价铬的去除效果模拟研究 总被引:1,自引:0,他引:1
通过土柱实验模拟地下水环境,研究以发酵树皮为主要反应介质的渗透性生物墙对地下水中六价铬的去除效果,为六价铬污染地下水的修复提供方法和依据。结果表明,模拟生物墙运行数天后,墙内形成弱碱性(pH 7~8)、强还原(Eh<-100 mV)环境,有利于六价铬转化为三价铬并生成沉淀。在进水六价铬浓度为20 mg/L、水流速度为3.7 cm/d的运行条件下,3周期间生物墙对六价铬的去除率稳定在98%左右,生物墙内沿水流方向三价铬的浓度先上升后下降(最高达6.6 mg/L),出水三价铬约为1.0 mg/L。吸附和微生物转化是生物墙对水中六价铬去除的主要反应。 相似文献
876.
Na Zhang Yu Yang Yu Liu Shu Tao 《Journal of environmental science and health. Part. B》2013,48(7):649-656
Octanol-air partition coefficients (KOA) and supercooled liquid vapor pressures (PL) of nine organochlorine pesticides (OCPs) including p,p′-DDE, p,p′-DDD, o,p′-DDT, o,p′-DDE, o,p′-DDD, α-HCH, β-HCH, γ-HCH, δ-HCH were determined as functions of temperature using a gas chromatographic retention time method. Among them, the KOA of o,p′-DDE and o,p′-DDD and the PL of o,p′-DDE, o,p′-DDD, β-HCH and δ-HCH were determined for the first time. The determined KOA and PL values of investigated compounds at 25°C ranged from 3.14 × 107 (α-HCH) to 3.76×109 (p,p′-DDD), and 8.95×10? 4 Pa (p,p′-DDD) to 1.08×10? 1 Pa (α-HCH), respectively. The KOA and PL data were compared with published data. The KOA values of o,p′-DDT at 25°C were 3.23×109, higher than o,p′-DDE (1.02×109) and o,p′-DDD (2.01×109), indicating o,p′-DDT were more preferred to partition in soil compared with the metabolites. The KOA values were lower and PL values were higher for o,p′-DDE and o,p′-DDD, compared with their p,p′-isomeric counterparts, leading to a potential difference in behavior and fate of these isomers. The discrepancies among chemicals are obvious, which reflected in the increasing KOA and decreasing PL values in order of α-HCH, γ-HCH, β-HCH, δ-HCH, o,p′-DDE, p,p′-DDE, o,p′-DDD, o,p′-DDT, p,p′-DDD. For each compound, the LogKOA decreased linearly with reciprocal absolute temperature, while LogPL had a significant positive correlation with the inverse absolute temperature. The present study suggested that the method of gas chromatographic retention time was appropriate to measure the KOA and PL of a number of OCPs. 相似文献
877.
Fu-Liu Xu Xiang-Zhen Kong Wei He Ning Qin Ying Zhu Shu Tao 《Environmental science and pollution research international》2013,20(4):2009-2019
The levels of hexachlorocyclohexanes (HCHs) in the sediments from Haihe Plain, China, were measured by a gas chromatograph with a 63Ni microelectron capture detector. The spatial distributions, possible sources, and potential ecological risks of these compounds were analyzed. The residual level of total HCHs was 33.84?±?173.37 ng?g?1 dry weight (d.w.) with ranges of 0.13?~?1,107.41 ng?g?1 d.w. Much higher ΣHCH contents were found in the lower reaches of some rivers and in the mouth of the main stream receiving tributaries. The predominance of β-HCH (36 %) in the sediments was similar to that in the soils from Haihe Plain. The high percentages of γ-HCH (23–41 %) could be detected at 25 % of the sampling sites in the seven river systems. There were statistically significant positive relationships between the contents of HCHs and total organic carbon. Lindane was identified as the primary source of HCHs in the sediments, and it seemed that recent illegal lindane inputs still existed in some areas in Haihe Plain, as indicated by the α-/γ-HCH and β-/(α?+?γ)-HCH ratios. Severe potential ecological risks of γ-HCH to benthic organisms at some sampling sites were found based on the consensus-based sediment quality guidelines. 相似文献
878.
Hongzhi He Haishuo Gao Guikui Chen Huashou Li Hai Lin Zhenzhen Shu 《Environmental science and pollution research international》2013,20(10):7301-7308
Perchlorate contamination in water is of concern because of uncertainties about toxicity and health effects, impact on ecosystems, and possible indirect exposure pathways to humans. Therefore, it is very important to investigate the ecotoxicology of perchlorate and to screen plant species for phytoremediation. Effects of perchlorate (20, 200, and 500 mg/L) on the growth of four wetland plants (Eichhornia crassipes, Acorus calamus L., Thalia dealbata, and Canna indica) as well as its accumulation in different plant tissues were investigated through water culture experiments. Twenty milligrams per liter of perchlorate had no significant effects on height, root length, aboveground part weight, root weight, and oxidizing power of roots of four plants, except A. calamus, and increasing concentrations of perchlorate showed that out of the four wetland plants, only A. calamus had a significant (p?<?0.05) dose-dependent decrease in these parameters. When treated with 500 mg/L perchlorate, these parameters and chlorophyll content in the leaf of plants showed significant decline contrasted to control groups, except the root length of E. crassipes and C. indica. The order of inhibition rates of perchlorate on root length, aboveground part weight and root weight, and oxidizing power of roots was: A. calamus > C. indica > T. dealbata > E. crassipes and on chlorophyll content in the leaf it was: A. calamus > T. dealbata > C. indica > E. crassipes. The higher the concentration of perchlorate used, the higher the amount of perchlorate accumulation in plants. Perchlorate accumulation in aboveground tissues was much higher than that in underground tissues and leaf was the main tissue for perchlorate accumulation. The order of perchlorate accumulation content and the bioconcentration factor in leaf of four plants was: E. crassipes > C. indica > T. dealbata > A. calamus. Therefore, E. crassipes might be an ideal plant with high tolerance ability and accumulation ability for constructing wetland to remediate high levels of perchlorate polluted water. 相似文献
879.
Nitrate facilitates cadmium uptake, transport and accumulation in the hyperaccumulator Sedum plumbizincicola 总被引:4,自引:0,他引:4
Pengjie Hu Yong-Gen Yin Satoru Ishikawa Nobuo Suzui Naoki Kawachi Shu Fujimaki Masato Igura Cheng Yuan Jiexue Huang Zhu Li Tomoyuki Makino Yongming Luo Peter Christie Longhua Wu 《Environmental science and pollution research international》2013,20(9):6306-6316
The aims of this study are to investigate whether and how the nitrogen form (nitrate (NO3 –) versus ammonium (NH4 +)) influences cadmium (Cd) uptake and translocation and subsequent Cd phytoextraction by the hyperaccumulator species Sedum plumbizincicola. Plants were grown hydroponically with N supplied as either NO3 – or NH4 +. Short-term (36 h) Cd uptake and translocation were determined innovatively and quantitatively using a positron-emitting 107Cd tracer and positron-emitting tracer imaging system. The results show that the rates of Cd uptake by roots and transport to the shoots in the NO3 – treatment were more rapid than in the NH4 + treatment. After uptake for 36 h, 5.6 (0.056 μM) and 29.0 % (0.290 μM) of total Cd in the solution was non-absorbable in the NO3 – and NH4 + treatments, respectively. The local velocity of Cd transport was approximately 1.5-fold higher in roots (3.30 cm h?1) and 3.7-fold higher in shoots (10.10 cm h?1) of NO3 –- than NH4 +-fed plants. Autoradiographic analysis of 109Cd reveals that NO3 – nutrition enhanced Cd transportation from the main stem to branches and young leaves. Moreover, NO3 – treatment increased Cd, Ca and K concentrations but inhibited Fe and P in the xylem sap. In a 21-day hydroponic culture, shoot biomass and Cd concentration were 1.51 and 2.63 times higher in NO3 –- than in NH4 +-fed plants. We conclude that compared with NH4 +, NO3 – promoted the major steps in the transport route followed by Cd from solution to shoots in S. plumbizincicola, namely its uptake by roots, xylem loading, root-to-shoot translocation in the xylem and uploading to the leaves. S. plumbizincicola prefers NO3 – nutrition to NH4 + for Cd phytoextraction. 相似文献
880.