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921.
我国十分重视对突发性水污染事件的监测和处置.本研究设计了一种实时在线监测重金属污染事件的漂浮阴极沉积物-微生物燃料电池传感器(漂浮阴极SMFC传感器).该传感器阳极埋设在淹水土壤中,阴极漂浮在水面作为污染响应元件,并向阴极分别加入Zn2+、Cd2+、Co2+、Ni2+、Pb2+、Cu2+、Cr6+溶液以模拟水体重金属污染事件,以探究该传感器电信号对不同重金属污染的响应特征及机制.结果显示,Cu2+和Cr6+污染引起传感器出现明显的电压峰,而其他5种重金属污染则未引起明显的电信号响应.该传感器电压信号对Cu2+污染的最低检测限为5 mg·L-1,灵敏度为1.06 mV·L·mg-1,线性范围为5~40 mg·L-1;Cr6+污染的最低检测限为40 mg·L-1,灵... 相似文献
922.
DOP与Pb单一及复合污染对土壤酶活性的影响 总被引:4,自引:1,他引:3
以4种土壤酶活性为指标,通过室内模拟试验研究w(DOP)为10,50和500 mg/kg与w(Pb)为300 mg/kg下的单一及复合污染对土壤过氧化氢酶、脲酶、磷酸酶、转化酶活性的影响. 结果表明,在试验条件下4种土壤酶活性受到不同程度的抑制,其中转化酶最为敏感,其活性可作为表征DOP与Pb复合污染的重要参考指标. 试验期(56 d)内,DOP与Pb复合污染的交互作用类型与污染物浓度水平有关;DOP与Pb复合污染对过氧化氢酶活性具有协同作用;对转化酶活性以拮抗作用为主;对脲酶活性的影响,低浓度水平时表现为协同作用,中、高浓度水平时表现为拮抗作用;对磷酸酶活性的影响,低浓度水平时表现为拮抗作用,高浓度水平则主要表现为协同作用. 相似文献
923.
924.
本文对N2O、CO2两种温室气体的研究工作进行了评述,重点介绍了土壤脱氮-分解模型(DNDC)的起始原由、发展过程及其结构.并通过对模型在不同国家和地区的灵敏度检验,表明与实测结果非常吻合,得出了非常重要的结论.这一模型不仅对N2O、CO2等温室气体的全球变化研究有重要意义.而且对土壤农业耕作实践也有指导作用,但这些结论有待于进一步的详细研究. 相似文献
925.
党中央提出科学发展观及建设社会主义新农村任务至今,乡村建设研究在学术界已日益成为热点,而小城镇在乡村建设的过程中发挥着主导作用,因而,小城镇建设是乡村建设工作中的重要任务.对于小城镇而言,建设首先就会涉及到合理的"量",即小城镇的规模合理性问题.由此,可以看出,与党中央政策同步,小城镇的规模合理性问题也必然将成为社会和学术界关注的焦点,对此问题进行研究迫在眉睫.与小城镇在我国城市化进程中的重要地位相结合,研究小城镇规模合理性问题的重要性凸显.本文在翔实把握国内外相关研究的基础上,从区域、生态、经济、社会综合视点同时切入,使用定性研究与定量研究相结合的研究方法,通过对湖北省武汉市柏泉镇合理规模的实例研究,提出了相关研究结论. 相似文献
926.
Zhao Y Duan L Lei Y Xing J Nielsen CP Hao J 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2726-2732
China’s strategies to control acidifying pollutants and particulate matter (PM) may be in conflict for soil acidification abatement. Acidifying pollutant emissions are estimated for 2005 and 2020 with anticipated control policies. PM emissions including base cations (BCs) are evaluated with two scenarios, a base case applying existing policy to 2020, and a control case including anticipated tightened measures. Depositions of sulfur (S), nitrogen (N) and BCs are simulated and their acidification risks are evaluated with critical load (CL). In 2005, the area exceeding CL covered 15.6% of mainland China, with total exceedance of 2.2 Mt S. These values decrease in the base scenario 2020, implying partial recovery from acidification. Under more realistic PM control, the respective estimates are 17.9% and 2.4 Mt S, indicating increased acidification risks due to abatement of acid-neutralizing BCs. China’s anthropogenic PM abatement will have potentially stronger chemical implications for acidification than developed countries. 相似文献
927.
Wang S Li B Zhang M Xing D Jia Y Wei C 《Environmental science and pollution research international》2011,19(7):2820-2831
Purpose
Due to the fast development of industry and the overuse of agrichemicals in past decades, Lake Taihu, an important source of aquatic products for Eastern China, has simultaneously suffered mercury (Hg) contamination and eutrophication. The objectives of this study are to understand Hg transfer in the food web in this eutrophic, shallow lake and to evaluate the exposure risk of Hg through fish consumption.Methods
Biota samples including macrophytes, sestons, benthic animals, and fish were collected from Lake Taihu in the fall of 2009. The total mercury (THg), methyl mercury (MeHg), ??13C and ??15N in the samples were measured.Results and discussion
The signature for ??15N increased with the trophic levels. Along with a diet composed of fish, the significant relationship between the ??13C and ??15N indicated that a pelagic foraging habitat is the dominant pathway for energy transfer in Lake Taihu. The concentrations of THg and MeHg in the organisms varied dramatically by ??3 orders of magnitude from primary producers (macrophytes and sestons) to piscivorous fish. The highest concentrations of both THg (100 ng g?1) and MeHg (66 ng g?1), however, were lower than the guideline of 200 ng g?1 of MeHg for vulnerable populations that is recommended by the World Health Organization (WHO). The daily intake of THg and MeHg of 92 and 56 ng day?1 kg?1 body weight, respectively, was generally lower than the tolerable intake of 230 ng day?1 kg?1 body weight for children recommended by the Joint FAO/WHO Expert Committee on Food Additives. Significant relationships between the ??15N and the logarithm of THg and MeHg showed an obvious biomagnification of Hg along the food web. The logarithmic bioaccumulation factor of MeHg in the fish (up to 5.7) from Lake Taihu, however, was relatively low compared to that of other aquatic ecosystems.Conclusion
Health risk of exposure to Hg by consumption of fish for local residents is relatively low in the Lake Taihu area. Dilution of Hg levels in the phytoplankton induced by eutrophication is a possible factor inhibiting accumulation of MeHg in fish in eutrophic Lake Taihu. 相似文献928.
太湖流域(苏州片)水质同步监测调查与评价 总被引:1,自引:0,他引:1
黄兴 《环境监测管理与技术》1999,11(4):27-28
综合分析了太湖流域(苏州片)达标排放前后的水质变化情况,讨论了达标排放与水质变化之间的关系,评价了水污染控制的效果。 相似文献
929.
The Conversion of Cropland to Forest and Grassland Program (CCFG), which was initiated by the Chinese government in 1999,
is a cropland retirement program with integrated objectives for ecological preservation and local development. The purpose
of this article was to study the influencing factors of attitude and economic strategies in rural households toward the CCFG.
Rural households’ knowledge, attitude and economic strategies toward the CCFG were investigated through a questionnaire survey
in Qira, China. Influencing factors of attitude and strategies of households were analyzed using a logit model technique.
The analysis indicated that household’s income level, environmental knowledge of the program, and program implementation were
significant influencing factors in a household’s attitude toward the CCFG, while major influencing factors of household strategies
were their regional background and availability of income generation sources. Meaningful association was not found between
attitude and strategy choices. Rich households had more strategy choices, while poor households were usually confined to low
input strategies with uncertain income. To sustain their livelihood, the poor need extra assistances in marketing, loan granting,
employment training, information, and technical services. 相似文献
930.
A/O-膜生物反应器和A~2O系统中有机物分子量分布的对比研究 总被引:3,自引:1,他引:2
采用凝胶过滤色谱(GPC)对A/O-膜生物反应器(A/O-MBR)和A2O系统中有机物分子量分布进行了对比研究.结果表明,A/O-MBR系统中由进水到好氧滤液的有机物分子量分布依次变宽,其趋势恰好与A2O系统相反;A/O-MBR好氧滤液的有机物分子量分布远宽于A2O好氧滤液.A/O-MBR好氧滤液中重均分子量(Mw)>107 u的有机物占总有机物质量的3.4%,表明正是由于膜的截留作用导致这类大分子有机物在MBR中的累积,而无法像A2O系统一样随出水流走;A/O-MBR系统各段污泥混合液的胞外聚合物(EPS)的分子量分布较分散,说明A/O-MBR系统中微生物新陈代谢产物多,并在膜的截留作用下最终造成了这些产物在膜表面大量的沉积. 相似文献