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1.
节能减排不仅是推进我国国民经济又好又快发展的核心要义,也是应对全球气候变化的迫切需要.在我国,要实现到2020年单位国内生产总值的二氧化碳排放比2005年下降40%-45%的约束性目标,需要进行艰难的产业结构调整、能源消费结构调整和经济发展阶段跨越,并应采取体制、政策、技术和管理等综合推进措施.包括政府投资、税收、政府采购和财政贴息在内的财税政策措施对于推进我国节能减排至关重要.本文认为,政府投资政策应重在支持高新技术产业研发应用,经由产业结构调整促进节能减排;税收政策应立足于综合采取增设环境污染税、低技术污染税以及税收优惠和减免等激励和惩罚并重措施;政府采购应通过扩大高效节能减排产品市场需求,引导企业生产行为;财政贴息则应侧重于解决企业节能减排投资以及技术改造过程中的资金约束.  相似文献   

2.
山东省水泥行业CO_2减排关键技术的实施分析   总被引:1,自引:1,他引:0  
由于社会对水泥需求的不断增长,多年来山东省水泥工业一直处于快速发展时期。作为国民经济的基础工业同时也是高耗能行业,山东省水泥行业面临着巨大的CO2减排压力。同时,技术自身的先进性决定了其相应的减排潜力,而减排效果的实现程度则取决于技术的推广度。在技术的推广过程中,其减排潜力、减排成本以及相关的政策支持都是关键性的影响因素,针对技术实施障碍进行深入的分析和探讨对实际减排效果的预测具有重要的意义。本研究利用长期能源替代规划系统软件建立了LEAP-Shandong Cement模型,对山东省水泥行业的CO2排放量及相应的减排潜力进行了模拟评估。到2020年,相对于基准情景,政策情景和技术情景下的减排潜力分别为8.2%和15.6%。山东省水泥行业实现减排主要依靠窑型的替代和相应技术的进步,其中余热发电技术改进为近期的重点减排技术,在水泥行业减排兼具显著的环境、经济和社会效益。  相似文献   

3.
工程减排、结构减排和监督管理减排是实现我国污染物减排的三个主要措施,近年来我国SO2的排放呈现出下降的态势,本文选取电力、钢铁和水泥这3个重要行业,测算了在"十一五"以来SO2的减排效果,以及由其带来CO2减排的协同效果。结果显示,"十一五"期间,3个主要行业减少污染物排放超过1 000万t,其中工程减少污染物排放超过700万t,结构减少污染物排放300万t。由此带来的协同效果显示,由于结构减排带来了超过7亿t CO2的减排,而由于工程效应减少污染物的同时带来的CO2增加500万t,因此总计带来7-8亿t CO2的减排。而"十二五"前两年减少污染物排放400万t,其中工程减少污染物排放350万t,结构污染物排放减少了40万t。由此带来的协同效果显示,由于结构减排减少了CO2排放1.74亿t,而由于工程效应减少污染物的同时带来的CO2的增加量为200万t,因此总计带来1.72亿t CO2的减排。结构减排和工程减排两种措施可以在行业内实现降低污染物的排放,但是其贡献程度由于行业的差异有所不同。"十一五"期间电力行业较多是依靠工程减排实现SO2排放的降低,而水泥和钢铁行业则更多是依靠行政命令如关停落后产能和机组实现污染物的减排,显示出电力行业通过技术实现污染物的减排,而其他两个行业则主要靠调整结构来实现减排。电力行业中的末端治理技术即工程减排贡献了大部分的污染物减排,但是与此同时由于末端治理技术会导致能源消耗的增加,即引起CO2排放的增加,因此污染物的协同控制效果较差,而钢铁和水泥行业的污染物减排则由于更多是通过结构调整的手段,如关停落后产能和机组,因此其协同效果较为显著。"十三五"期间,需要继续控制双高产业的发展,强化"前端"污染物控制减排,夯实结构减排的协同成效,加大工程减排的实施,缩小减排工程能力和实际减排效果的差距,实现"末端"污染物减排,加强"前端"审批和"中段"运行管理效果。  相似文献   

4.
本文构建了一个由代表性家庭、政府和八个不同行业组成的一般均衡模型,同时在模型中嵌入了碳强度、碳交易两种不同的环境政策工具,并基于2007年我国投入产出表数据进行校准。本文通过数值分析指出我国约束全行业的碳减排政策对福利损失的边际影响最小,约束重点行业的碳减排政策对实际GDP的影响存在倒"U"型关系,在碳强度目标约束不高于17%时,碳强度政策对社会福利的损失影响要低于碳交易政策;在碳强度目标约束不高于21%时,约束重点行业的碳减排政策对实际GDP的边际损失影响要低于约束全行业的政策。我国的碳减排政策在当前碳强度约束目标下实现了环境质量改善和经济持续增长的双重红利,该结论支持了环境Porter假说。双重红利产生的原因是由于碳减排政策使得资源要素使用成本上升,进而提高了劳动等低碳要素需求,使得行业之间生产要素重新配置,在一定情况下实现了经济增长和环境改善。进一步,本文给出了环境规制政策的设计方案,根据边际减排相等以实现总减排成本最小化的原理,给出了约束全行业减排的环境政策下各行业碳强度的任务分解,通过模拟计算各行业的边际减排成本,可以为政府根据行业维度制定更为科学、合理的减排方案提供理论和实践支持。此外,本文还估计了产业需求变动、行业最终消费结构变动、行业全要素生产率变动、行业需求中间投入品替代弹性技术变动等各种经济发展方式的变化对碳排放量和碳强度的边际影响,深入分析和理解经济发展方式与碳强度变化之间的内在联系,有利于识别经济系统中相互关联的各种因素如何对碳强度的政策目标产生影响。本文的研究指出我国应大力提高各项中间投入品的单位碳排放节能技术水平,这是降低碳排放强度最直接的、最有力的政策措施。政府应进一步加大投入,通过引进、消化和吸收国际先进技术、国际合作开发和自主创新等方式,鼓励企业使用清洁能源,提高工业废气、尾气的处理技术水平,鼓励低碳部门的技术研发,鼓励企业提高资本、劳动的生产技术水平,提高中间投入品的使用效率,这些对于实现我国总体的减排目标具有十分重要的意义。  相似文献   

5.
工业废水排放造成的环境污染已经成为制约中国工业经济转型的重要瓶颈,因此合理测度工业行业废水排放效率和减排潜力,可以为制订合适的工业行业废水排放减排措施提供一定的科学依据。考虑到不同工业行业间生产技术的差异性,本文在共同前沿理论框架下,基于规模方向性距离函数对我国2004—2015年37类工业行业的废水排放效率和减排潜力进行测度,并从静态和动态视角下揭示其差异性及变动趋势。研究结果显示:废水低、中等和高排放组的排放效率多年均值分别为0.512、0.250和0.168,减排潜力分别高达48.8%、75%和83.2%,减排潜力巨大。三组的技术落差率历年均值分别为0.992、0.377和0.221,说明只有废水低排放组内各工业行业的技术水平基本达到该区域的潜在最优技术水平,而其余两组则均未实现组内最优。行业间废水排放效率和减排潜力差异性较大,效率高减排潜力小的行业主要集中在废水排放量低且技术落差率高的行业,而效率低减排潜力大的行业则主要集中在废水排放量高且技术落差率低的行业。考察期内全国工业行业废水排放效率在逐年提高,废水减排潜力在逐渐降低,但是行业间差距在变大,并逐渐呈现两极分化现象。最后基于实证分析结果,本文提出了若干政策建议,包括:全面提高工业科技投入,增强管理能力,提升工业废水排放效率,减少废水排放;分行业制定工业废水排放标准,提出分类技术改进措施;积极推进行业间在废水处理技术和先进管理理念方面的交流与合作,实现工业内所有行业废水排放效率的普遍提升和改善。  相似文献   

6.
运用方向性距离函数和Malmquist-Luenberger生产率指数对2015—2050年中国工业绿色增长进行模拟预测,通过对能源消耗5种情景,以及9条二氧化碳减排路径的设计,评估45种节能减排政策组合对工业潜在产出和损失的影响,以找寻节能减排的最优路径。在此基础上,模拟预测最优路径下中国工业产出增长和绿色生产率增长的变动趋势,并以绿色生产率的变化作为判断中国工业能否实现双赢发展的依据,研究表明:(1)2015—2050年间,在45种节能减排政策组合中,节能减排行为均造成工业产出的潜在损失,但由于产出增长的幅度较大,最终的增长净值为正。经过综合评价,产出增速7%、能耗增速3.8%,工业各行业在2040年达到二氧化碳排放峰值是最优的节能减排路径。(2)在最优节能减排路径下,全行业绿色生产率在预测周期内平均增长0.53%,共有29个分行业的绿色生产率保持增长或不出现倒退,因而中国工业绿色增长即实现双赢发展的前景可期。从绿色生产率的驱动力来看,期初绿色生产率的提升主要依靠技术效率拉动,而中期过后,技术进步在不断累积、消化、吸收中开始持续释放增长效应,自2035年开始,绿色生产率的提升主要靠技术进步的推动。(3)高能耗、高排放行业更是节能减排行为的受益者,而其他行业也并非节能减排行为的受损者。相较中低能耗行业,高能耗行业绿色生产率增长最快,相较中低排放行业,高排放行业的绿色生产率增长最快。与全行业一致,各类行业绿色生产率及其分解的走势也体现出前期技术进步负效应和技术效率正效应共同作用,而中后期技术进步成为绿色生产率增长的主要来源。  相似文献   

7.
作为我国特别行政区之一,澳门正遭受以极端天气为代表的气候变化影响,并且这一现实已经严重威胁到澳门经济发展和城市安全。研究温室气体排放清单和排放特征,进而采取相应措施应对和减缓气候变化带来的影响已经成为澳门社会各界的共识。本文在量化澳门三个范畴的温室气体特征的基础上,识别了典型行业温室气体排放特点,并提出了促进澳门实现温室气体减排的有效措施和路径。研究显示:2000—2017年间,澳门范畴1、范畴2和范畴3排放均有不同程度的增加,并且没有任何一个范畴的排放量已达到峰值。2017年三者排放量分别为226.80万t CO_(2e)、450.47万t CO_(2e)和558.49万t CO_(2e)。电力行业和交通运输(包括陆运、海运和空运)已经成为澳门范畴1排放最重要的贡献者,2017年贡献率分别为38%和37%。2017年澳门范畴1人均温室气体排放量为3.47 t CO_(2e)/人,约为范畴2和范畴3同期水平的50%和41%。总体而言,澳门范畴1碳强度明显低于范畴2和范畴3,并且三者仍在逐年下降。情景分析结果显示,通过运输业电气化、本地电力结构优化、废弃物管理及再利用和其他燃料节能减排四个路径的减排措施,可以将澳门范畴1的温室气体排放量在2017年基础上削减90%。因此,调整电力发展政策是澳门温室气体减排的最有效措施之一,特区政府的减排重点应放在能源消费电气化、增加清洁电力比例上。  相似文献   

8.
二氧化碳边际减排成本可以反映环境质量与经济增长的关系,既是气候政策制定的科学基础,也是实现碳达峰、碳中和目标的关键因素。该研究基于三种方向性距离函数的行为模式构建三种二氧化碳边际减排成本的计算方法,测度中国30个省份(未涉及西藏和港澳台地区)1998—2019年间三种二氧化碳边际减排成本,并从全国、区域和省份三个层面进行分析。在进一步分析中,从减排空间和技术进步两个视角构建二氧化碳边际减排成本影响机制的理论框架,同时进行实证检验。测算结果表明:①经济主体从“传统-弱”模式时边际减排成本为负,从“传统-强”模式时边际减排成本趋近于零,从“弱-强”模式时边际减排成本均为正。②三种测量方法下边际减排成本均呈现上升、下降、上升的“N”型;区域规律一致,均为中部较高,东、西部较低;不同区域和省份间同一种边际减排成本的差别较大。影响机制的进一步分析显示:①减排空间和技术进步是影响二氧化碳边际减排成本的最为重要的两个因素,先后起主导作用。②只有当减排空间足够大,经济行为主体处于粗放型发展阶段和节能减排政策处在初始时期这两个条件同时满足时,节能减排政策才能起到降低边际减排成本的效果。③技术进步具有周期性。现阶段中国绿色技术处于快速发展的初步成长期,对技术的投入处于沉没成本阶段。虽然削减减排空间能够倒逼技术进步,但是技术进步并不能够起到显著降低减排成本的效果。因此,在减排政策的制定中要注重阶段性和区域差异,持续推进和完善碳排放权交易市场,考虑技术进步前期“沉默发酵”的特性,在中西部地区承接产业时要协调推进可持续发展。  相似文献   

9.
煤炭是我国重要战略性基础资源,在能源消费结构中占主导地位,煤炭资源税改革对经济增长、行业发展和节能减排影响重大。本文构建动态递归CGE模型,采用GAMS软件以2%、5%和10%的税率区间分析煤炭资源税改革对行业发展、资源效率和减排的影响。研究表明:在节能减排方面,资源税改革能有效降低主要污染物排放、单位GDP能耗和能源消耗总量,提高能源利用效率,当采用10%的税率时节能减排效果最佳,可以有效抑制CO2和SO2排放,但短期内会对经济增长产生极大的负面影响,降低GDP增长,抑制开采业、工业、能源、运输业和农业等产业总产出;从长期看,适度的煤炭资源税税率能在经济增长可承受范围内最大限度降低主要污染物排放,实现节能减排和经济增长的均衡发展。因此,应重点研究资源税率设置的科学性,在不同主体和行业影响基础上,合理选择资源税税负水平,减轻资源税改革对社会经济发展的负面冲击,并通过政策引导其产业升级,提高节能减排效果。  相似文献   

10.
测算二氧化碳的边际减排成本有利于评估区域碳减排潜力与成本,也是落实区域碳交易政策的重要依据。在多投入-多产出的生产效率模型框架下,本文采用二次型方向距离函数,研究了全国30个省份2000—2012年期间的碳边际减排成本及其差异的时空演化特征。二次型方向距离函数通过引用时间变量,反应环境治理的中性技术进步,因此研究方法能充分利用参数估计的灵活性。研究结果显示:1二氧化碳的边际减排成本平均约为1 519元/吨,远高于我国碳市场的交易价格,表明当前试点的自愿性碳交易政策是无效的;2区域碳边际减排成本的泰尔指数分解表明,东中西部地区的减排成本存在明显的地区性差异性,且随着时间的推进,碳减排空间逐渐变小。减排成本的地区性差异表明环境规制政策并不能保证各地区碳治理成本的边际均等原则,而利用政策工具,促使碳排放权从治理成本较高的地区转移至成本较低的地区,可以减少总治理成本,实现总量控制目标。本文建议:一方面,为实现国家碳减排的总体宏观目标,各区域要加强合作,相互借鉴成功的碳减排技术与经验等,在执行政策上,应尝试执行区域协同治理机制,努力降低总减排成本;另一方面,各区域在推进产业结构调整、城镇化及能源消费结构替代过程中要遵从循序渐进原则,避免碳减排成本过度波动,增加减排难度。  相似文献   

11.
BackgroundEvidence is growing for the beneficial impacts of natural outdoor environments on health. However, most of the evidence has focused on green spaces and little evidence is available on health benefits of blue spaces and about possible mediators and modifiers of such impacts. We investigated the association between natural outdoor environments (separately for green and blue spaces) and health (general and mental) and its possible mediators and modifiers.MethodsCross-sectional data from adults interviewed in Catalonia (Spain) between 2010 and 2012 as part of the Catalonia Health Survey were used. The collected data included sociodemographic characteristics, self-perceived general health, mental health, physical activity and social support. Indicators of surrounding greenness and access to natural outdoor environments within 300 m of the residence and degree of urbanization were derived for residential addresses. Associations were estimated using logistic regression and negative binominal models.ResultsGreen spaces were associated with better self-perceived general health and better mental health, independent of degree of urbanization. The associations were more consistent for surrounding greenness than for access to green spaces. The results were consistent for different buffers, and when stratifying for socioeconomic status. Slightly stronger associations were found for women and residents of non-densely populated areas. No association was found between green spaces and social contacts and physical activity. The results for blue spaces were not conclusive.ConclusionGreen spaces are associated with better general and mental health across strata of urbanization, socioeconomic status, and genders. Mechanisms other than physical activity or social support may explain these associations.  相似文献   

12.
循环经济与节能减排解析   总被引:3,自引:0,他引:3  
目前我国经济增长模式是粗放的、不循环的经济增长模式,经济发展过程中存在着高增长、高能耗、高环境问题,作者通过一系列的数据对比和分析,指出当前发展循环经济,促进节能减排是我国经济发展过程中面临的第一要务。胡锦涛同志在党的十七大报告中提出一定要“落实节能减排工作责任制”,更表明了我国当前发展循环经济,促进节能减排的决心。本文首先提出循环经济与节能减排的相关概念及含义;再以重点行业中的电力、钢铁行业如何搞好能源资源节约和“三废”综合利用为例对我国发展循环经济、促进节能减排进行了实证分析;最后提出要通过加快资源价格机制的改革、促进技术创新、完善政策法规体系、转变领导片面追求GDP增长的认识等措施来达到发展循环经济、促进节能减排的目标。  相似文献   

13.
中国地表权、地下权概念、应用模式及相关问题分析   总被引:2,自引:0,他引:2  
文章通过对地表权、地下权相关法律概念的梳理,指出地表权、地下权概念界定的复杂性,借鉴《商业词典》对地表权和地下权的定义,探讨了在中国矿产资源一元所有制及土地二元所有制并存的情形下,地表权与地下权的应用模式、相关产权界定及存在的问题。文章分三种情形对二者的应用模式进行了探讨,指出:地表权与地下权相分离的模式是符合中国国情的一种合理选择,但是在具体实践中却存在农村集体作为土地拥有者的地位没有得到应有的尊重、矿业权主体行政审批问题严重、矿产资源的国家所有权权益没有得到应有的体现、矿产资源开发中的环境产权界定不清晰等问题;在探讨中指出两个启迪性的思路:一是使农村集体参与矿产资源开发收益分成模式;二是在现有的征地制度下,理顺价格机制,建立有效的土地流转市场,在土地使用权转让中,给予土地所有者以价格补偿。文章进一步对矿产资源开发中的土地所有权界定、税费问题、土地价格补偿及环境产权分配给予相应的分析并给出建议。  相似文献   

14.
加拿大环境与可持续发展科技创新及对我国的启示   总被引:1,自引:0,他引:1  
加拿大重视环境保护与可持续发展中的科技创新,在全联邦范围内营造了"政府引导、企业主体、国民支持"的良好创新氛围,形成了"以科技创新支撑环境产业发展,以环境产业促进环境保护与可持续发展"的鲜明环保特色,走出了一条科技创新、产业发展、环境保护和可持续发展三者协同发展、相互制衡、良性循环的发展路子,值得我国借鉴.在我国的环境与可持续发展科技创新中,存在着创新能力不足、产学研合作薄弱、产业化乏力等问题.本文通过中加比较,探讨了我国实施环境与可持续发展科技创新的对策思路,即政府应完善环保法规政策、健全环保标准和管理体系;应增加科研投入,建立政府调控下的市场化投资体系和环境科技的产业化发展;应选择重点领域实现优先发展,突破瓶颈产业;应重视合作创新,加强部门合作,科研机构合作以及国际合作.  相似文献   

15.
The unhatched eggs of the following seabirds were analyzed to quantify PCBs, hexachlorobenzene (HCB), α-, β-, γ-, δ-hexachlorocyclohexanes (HCHs), o,p' and p,p' isomers of DDT, DDD and DDE: resident Adèlie (Pygoscelis adèliae, ADPE) and Emperor (Aptenodytes forsteri, EMPE) penguins, migrating snow petrel (Pagodroma nivea, SNPT) and South Polar skua (Catharacta maccormicki, SPSK) from the Ross Sea (East Antarctica); and migrating Brown skua (Catharacta antartica, BRSK) and resident ADPE from the Brainsfield Strait (West Antarctica). The general aims were to evaluate the contaminant accumulation in eggs of migrating and resident species in the two study areas, and to compare levels in penguins and skuas nesting in East and West Antarctica. PCB congener and HCH and DDT isomer profiles were also assessed. Comparisons were evaluated using seven PCB congeners (IUPAC nos. 28, 52, 101, 118+149, 138, 153, and 180), p,p'-DDE, ΣDDTs, and ΣHCHs. Higher contaminant concentrations were detected in migrating seabirds (South polar skua and brown skua)>sub-Antarctic species (snow petrel)>Antarctic species (penguins) from both the sampling sites, suggesting contamination events at lower latitudes for those birds migrating northward. HCHs showed the lowest concentrations in all species (from 0.03±0.03 ng/g wet wt in SPSK to 1.81±1.23 ng/g wet wt in ADPE from West Antarctica), and PCBs were the most abundant contaminants (from 4.34±2.15 ng/g wet wt. in EMPE to 53.41±19.61 ng/g wet wt. in brown skua). Among pesticides, it is relevant the detection of p,p'-DDT in Adèlie penguin from West Antarctica and in both species of skua; the detection of this pesticide can confirm its actual use in certain malaria-endemic countries from where it is transferred through the long range transport to the polar regions. Contaminants did not show any significant temporal trend during a ten year time span, from 1994/95 to 2004/05, in organisms collected in East Antarctica and they did not indicate any latitudinal gradient along the Ross Sea coasts.  相似文献   

16.
《Environment international》2012,38(8):1329-1335
The unhatched eggs of the following seabirds were analyzed to quantify PCBs, hexachlorobenzene (HCB), α-, β-, γ-, δ-hexachlorocyclohexanes (HCHs), o,p′ and p,p′ isomers of DDT, DDD and DDE: resident Adèlie (Pygoscelis adèliae, ADPE) and Emperor (Aptenodytes forsteri, EMPE) penguins, migrating snow petrel (Pagodroma nivea, SNPT) and South Polar skua (Catharacta maccormicki, SPSK) from the Ross Sea (East Antarctica); and migrating Brown skua (Catharacta antartica, BRSK) and resident ADPE from the Brainsfield Strait (West Antarctica). The general aims were to evaluate the contaminant accumulation in eggs of migrating and resident species in the two study areas, and to compare levels in penguins and skuas nesting in East and West Antarctica. PCB congener and HCH and DDT isomer profiles were also assessed. Comparisons were evaluated using seven PCB congeners (IUPAC nos. 28, 52, 101, 118 + 149, 138, 153, and 180), p,p′-DDE, ΣDDTs, and ΣHCHs. Higher contaminant concentrations were detected in migrating seabirds (South polar skua and brown skua) > sub-Antarctic species (snow petrel) > Antarctic species (penguins) from both the sampling sites, suggesting contamination events at lower latitudes for those birds migrating northward. HCHs showed the lowest concentrations in all species (from 0.03 ± 0.03 ng/g wet wt in SPSK to 1.81 ± 1.23 ng/g wet wt in ADPE from West Antarctica), and PCBs were the most abundant contaminants (from 4.34 ± 2.15 ng/g wet wt. in EMPE to 53.41 ± 19.61 ng/g wet wt. in brown skua). Among pesticides, it is relevant the detection of p,p′-DDT in Adèlie penguin from West Antarctica and in both species of skua; the detection of this pesticide can confirm its actual use in certain malaria-endemic countries from where it is transferred through the long range transport to the polar regions. Contaminants did not show any significant temporal trend during a ten year time span, from 1994/95 to 2004/05, in organisms collected in East Antarctica and they did not indicate any latitudinal gradient along the Ross Sea coasts.  相似文献   

17.
Abstract

Refrigerants used in refrigerators are an important source of ozone depleting substances released into the atmosphere, and can have a significantly negative effect on the hole in the ozone layer. But most emission of refrigerants is man-made, unreasonable and needless. Since in most emission cases the refrigerants are contained in the refrigerators, we can retrieve them by some technique that changes the ‘manual emission’ into manual retrieving. To promote the retrieval action and diminish the pollution, society can use economic, administrative and technical countermeasures, which can create a ‘good-cycle’ both ‘harnessing pollution and earning income simultaneously’, reinforce the motive of retrieving, and retrieve most proportion of refrigerants used by all refrigerators. This ‘good-cycle’ method can be easily promoted, and also a valuable way to promote other forms of environmental protection. The three countermeasures have almost no social cost, even no cost at all.  相似文献   

18.
Refrigerants used in refrigerators are an important source of ozone depleting substances released into the atmosphere, and can have a significantly negative effect on the hole in the ozone layer. But most-emission of refrigerants is man-made, unreasonable and needless. Since in most emission cases the refrigerants are contained in the refrigerators, we can retrieve them by some technique that changes the 'manual emission' into manual retrieving. To promote the retrieval action and diminish the pollution, society can use economic, administrative and technical countermeasures, which can create a 'good-cycle' both 'harnessing pollution and earning income simultaneously', reinforce the motive of retrieving, and retrieve most proportion of refrigerants used by'all refrigerators. This 'good-cycle' method can be easily promoted, and also a valuable way to promote other forms of environmental protection. The three countermeasures have almost no social cost, even no cost at all.  相似文献   

19.
Arsenic (As), a naturally occurring metallic element, is a dreadful health hazard to millions of people across the globe. Arsenic is present in low amount in the environment and originates from anthropogenic impact and geogenic sources. The presence of As in groundwater used for irrigation is a worldwide problem as it affects crop productivity, accumulates to different tissues and contaminates food chain. The consumption of As contaminated water or food products leads to several diseases and even death. Recently, studies have been carried out to explore the biochemical and molecular mechanisms which contribute to As toxicity, accumulation, detoxification and tolerance acquisition in plants. This information has led to the development of the biotechnological tools for developing plants with modulated As tolerance and detoxification to safeguard cellular and genetic integrity as well as to minimize food chain contamination. This review aims to provide current updates about the biochemical and molecular networks involved in As uptake by plants and the recent developments in the area of functional genomics in terms of developing As tolerant and low As accumulating plants.  相似文献   

20.
The adsorption properties of reference minerals may be considerably modified by the presence of the inorganic and organic coatings that are ubiquitous in soils. It is therefore important to assess the effect of such coatings to evaluate the relevance of adsorption studies on pure minerals. The adsorption of trace amounts of (85)Sr and (137)Cs has been studied in dilute suspensions for various minerals that are common components of soils: quartz, calcium carbonate, kaolinite, montmorillonite and illite. We studied the effect of coatings with either Fe or Al oxide with varying additions of soil-extracted humic or fulvic acid. Both adsorption and desorption were measured and data presented as distribution coefficients, Kd. No adsorption was detected on quartz and it was not possible to coat this surface. Adsorption on calcium carbonate was small and not influenced by coatings. Adsorption of Sr on the three clay minerals was very similar, enhanced by the Al-coating, but not affected by Fe and organic coatings. The presence of organic coatings decreased Cs adsorption on illite. Similar but smaller effects were seen on montmorillonite and kaolinite. Aluminum coating enhanced Cs adsorption on illite, whereas both inorganic coatings caused decreases in adsorption on montmorillonite, and there was no effect on kaolinite. Effects were not additive with mixed, organic-inorganic coatings. Adsorption of both Cs and Sr on all minerals was strongly irreversible, with Kd (desorption) being up to four-times greater than adsorption Kd. The ratio of desorption and adsorption Cs Kd values (an assessment of irreversibility) was inversely related to adsorption Kd. This is consistent with a decreasing contribution of high-affinity adsorption as adsorption increases, but may also reflect the partial loss of organic coatings during desorption.  相似文献   

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