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471.
472.
We tested the use of whole-body and subcellular Cu residues (biologically-active (BAM) and inactive compartments (BIM)), of the oligochaete Lumbriculus variegatus to predict Cu toxicity in fresh water. The critical whole-body residue associated with 50% mortality (CBR50) was constant (38.2-55.6 μg g−1 fresh wt.) across water hardness (38-117 mg L−1 as CaCO3) and exposure times during the chronic exposure. The critical subcellular residue (CSR50) in metal-rich granules (part of BIM) associated with 50% mortality was approximately 5 μg g−1 fresh wt., indicating that Cu bioavailability is correlated with toxicity:subcellular residue is a better predictor of Cu toxicity than whole-body residue. There was a strong correlation between the whole-body residue of L. variegatus (biomonitor) and survival of Chironomus riparius (relatively sensitive species) in a hard water Cu co-exposure. The CBR50 in L. variegatus for predicting mortality of C. riparius was 29.1-45.7 μg g−1 fresh wt., which was consistent within the experimental period; therefore use of Cu residue in an accumulator species to predict bioavailability of Cu to a sensitive species is a promising approach. 相似文献
473.
高分子量高纯度阳离子聚丙烯酰胺的合成 总被引:3,自引:0,他引:3
以丙烯酰胺与丙烯酰氧乙基三甲基氯化铵为单体,在复合引发剂的作用下,选择水溶液共聚法合成高分子量与高纯度阳离子型聚丙烯酰胺(CPAM)。实验表明,有机偶氮引发剂A用量0.5‰、氧化还原引发剂用量0.45‰、还原剂与氧化剂摩尔比2∶1、反应体系pH为4与反应时间5 h条件下,CPAM分子量为1 042万,且溶解性好。通过对聚合物残单含量影响因素添加剂用量、反应时间的研究,结果表明,添加剂EDTA和增溶剂D对残留AM含量影响小,而苯甲酸钠对聚合物残留AM的含量影响显著;延长反应时间至7 h,残单含量可降低至0.27%,CPAM的纯度高。通过与国内外3种同类型产品进行对比,结果表明,自制产品的分子量明显高于其他产品,且残单含量比国内产品降低了50%~75%。 相似文献
474.
为考察较低温度(<17℃)条件下添加微量金属元素对厌氧发酵产气量的影响,在发酵底物TS(含固率)为10%下采用10 L玻璃瓶作反应器,以牛粪为原料,向厌氧生物反应器中分别添加MnSO4、FeSO4·7H2O、电解锰渣,分析了厌氧消化系统运行过程中的产气量、COD(化学需氧量)和pH的变化。结果表明,锰元素能促进低温下牛粪的厌氧发酵,加速反应启动。当添加6 g MnSO4、100 g电解锰渣时,单位质量VS产气率分别为0.26 mL/g和0.64 mL/g,添加6 g FeSO4·7H2O与空白对照组均未见明显产气。 相似文献
475.
476.
填埋场中亚硝酸还原酶测定条件的优化 总被引:1,自引:0,他引:1
填埋垃圾中的含氮化合物经一系列生物脱氮作用,最终使得填埋场中的氮素得以消减,在这一过程中亚硝酸还原酶起着十分重要的作用。以填埋场中的填埋垃圾为研究对象,在土壤亚硝酸还原酶测定方法的基础上,对亚硝酸还原酶活性测定条件进行了优化。结果表明,填埋垃圾中的亚硝酸还原酶活性测定的最优条件为:垃圾样品风干温度25℃,2mL的1%NaNO2溶液和2.5 mL的1%葡萄糖溶液,抽气5 min,置于25℃的培养箱中培养24 h。优化后的测定条件相对标准偏差(RSD)小于1.27%,表明该方法具有较高的灵敏度和精密度。 相似文献
477.
Daniel Paska 《Natural resources forum》2010,34(3):200-210
The amount of electrical and electronic products is increasing rapidly, and this inevitably leads to the generation of large quantities of waste from these goods. Some of the generated e‐waste ends up in regions with sub‐standard recycling systems and may be processed under poor conditions. During uncontrolled incineration, halogenated dioxins and furans can be generated from brominated and chlorinated compounds in the products. In order to reduce the health and environmental risks involved in the recycling stage of the life cycle of electronics, an effective design‐for‐environment process must be established during the product development phase. Knowledge of the chemical substances in the product is crucial to being able to make informed decisions. Through full knowledge of the material content of procured components, phase‐outs of unwanted substances, such as halogenated substances, can be performed in an effective manner. Therefore, information is the key to success in phasing‐out substances; facilitating compliance of legal provisions for manufacturers of electrical and electronic devices; and improving the environmental footprint of products as they reach the end of the life cycle. After an introduction to the challenges of electronics waste management, this paper describes supply chain information systems and how they are used to facilitate substance phase‐outs in the electronics industry. Sony Ericsson has been working with phase‐outs of unwanted substances since it was founded in 2001. Through the introduction of a material declaration system that keeps track of all substances in the components used in the company's products, Sony Ericsson has been able to replace unwanted substances to improve environmental impacts at the recycling stage of a product. 相似文献
478.
Richard Bull Judith Petts James Evans 《Journal of Environmental Planning and Management》2010,53(8):991-1009
This paper takes a new look at the importance of context – institutional and political – in effective public engagement processes. It does so through a rare comparative opportunity to examine the effectiveness of processes of public engagement in two UK waste authorities, where the same waste company was involved as both the primary contractor for the delivery of the waste management service (including new energy-from-waste facilities) and, furthermore, the same staff delivered the public engagement. Interrogating these cases affords the opportunity to place flesh on the bones of the sometimes ‘abstract’ skeleton of context. While engagement processes support effective local governance in an era of partnerships and deliberative democracy, the paper identifies that the methods adopted cannot be played out devoid of detailed understanding and response to local context, including the strength of partnership working between the public and private sector, the degree of political support for engagement, and the extent to which a traditional institutional paternalism still dominates. 相似文献
479.
污泥热解残渣制备聚合氯化铝的实验研究* 总被引:1,自引:0,他引:1
含铝污泥热解或焚烧残渣制备聚合氯化铝的研究,有利于实现污水处理过程投加的铝盐絮凝药剂的回收与高效循环利用,减少污染物排放和资源消耗。针对辽河油田欢三联稠油污水处理污泥的热解残渣具有较高铝含量的特点,开展采用盐酸进行铝溶出及制备聚合氯化铝的实验研究。结果表明:焙烧温度为700~750℃,焙烧时间控制在1h即可。将经过焙烧活化的残渣在常温下进行酸溶,酸溶时间为2~5h,选用25%~30%盐酸,氧化铝与盐酸的摩尔比为1∶1.0~1∶1.2为宜。将溶出的铝溶液制备聚合氯化铝,在常温下采用CaO粉末来调节pH值为3.5,聚合反应时间为1d,即可得聚合氯化铝溶液。 相似文献
480.
Laura B. Brentner Sachiyo T. Mukherji Jerald L. Schnoor 《Environmental pollution (Barking, Essex : 1987)》2010,158(2):470-475
Phosphor imager autoradiography is a technique for rapid, sensitive analysis of the localization of xenobiotics in plant tissues. Use of this technique is relatively new to research in the field of plant science, and the potential for enhancing visualization and understanding of plant uptake and transport of xenobiotics remains largely untapped. Phosphor imager autoradiography is used to investigate the uptake and translocation of the explosives 1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene within Populus deltoides × nigra DN34 (poplar) and Panicum vigratum Alamo (switchgrass). In both plant types, TNT and/or TNT-metabolites remain predominantly in root tissues while RDX and/or RDX-metabolites are readily translocated to leaf tissues. Phosphor imager autoradiography is further investigated for use in semi-quantitative analysis of uptake of TNT by switchgrass. 相似文献