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541.
复合垂直流构建湿地净化酞酸酯的初步研究 总被引:5,自引:1,他引:5
为考察湿地对特殊污染物酞酸酯的净化作用,在温室中建造了专门用于酞酸酯研究的2套下行流-上行流湿地小试系统,1号系统邻苯二甲酸二丁酯(DBP)和邻苯二甲酸二(2-乙基已基)酯(DEHP)污染负荷分别为19.86mgL^-1和3.16mgL^-1,2号系统DBP和DEHP污染负荷分别为9.84mgL^-1和1.58mgL^-1,试验时间为45d。水力负荷为420Ld^-1。结果表明:构建湿地对人工配置污水中的酞酸酯有很好的净化效果。平均去除率达到99.95%以上,出水酞酸酯质量浓度为10^-9级,均低于国家排放标准(GB8978-1996). 相似文献
542.
QI ONG GAO 《Environmental and Ecological Statistics》1997,4(3):205-218
A simple model of rainfall redistribution within a terraced sandy grassland landscape has been developed. The model assumes that rainfall redistribution is driven by rainfall impulses and is controlled by characteristic field capacity of soils. When the rainfall intensity is large enough to render soil water content greater than its characteristic field capacity, the excessive soil water can drain very quickly by means of large amounts of non-capillary pores of sandy soils or by means of surface runoff. Exponential distribution of rainfall impulses was assumed and tested with measured daily rainfall at two meteorological stations in the sandy grassland area of north China. The model was solved to give the equivalent rainfall at each terrace in the landscape. 相似文献
543.
Heikens A Widianarko B Dewi IC De Boer JL Seinen W van Leeuwen K 《Environmental geochemistry and health》2005,27(5-6):409-418
In Asembagus (East Java, Indonesia) irrigation water is contaminated with effluent from the hyperacid Ijen Crater Lake resulting
in a low pH and high levels of various elements. As a first step towards a risk assessment, locally produced food items (rice,
maize, cassava leaf, cassava root, peanuts) were collected and concentrations of As, B, Ca, Cd, Co, Cu, Fe, Mg, Mn, Mo, Ni,
Pb, V, Zn were compared to samples from a reference area and with literature values. Further, concentrations in rice were
compared to total soil concentrations in paddy fields. Compared to the reference area, food items produced in the contaminated
area had increased levels of Cd, Co, Ni and Mn in particular, while levels of Mo were lower. In contrast, total soil concentrations
of Cd and Mn in particular have decreased whereas especially Mo was increased. In combination with the observed soil acidification,
it is likely that the bioavailable concentration of most elements in the contaminated soil is higher (except for Mo) due to
an increased weathering rate and/or input via the contaminated irrigation water. In terms of human health, concentrations in foods were generally within normal literature
values. However, it was observed that essential elements (in particular Fe) known for their inhibitory effects on e.g. Cd
and Mn toxicity did not accumulate in crops whereas Cd and Mn did. 相似文献
544.
Sondes Melliti Ben Garali Inès Sahraoui Pablo de la Iglesia Mohamed Chalghaf Jorge Diogène Jamel Ksouri 《Chemistry and Ecology》2020,36(1):66-82
ABSTRACTThe seasonal variations in Pseudo-nitzschia species and domoic acid (DA) concentration were investigated, at three shellfish farms in SW coastal Mediterranean. In parallel, the toxicity of mussels was tested. Two distinct groups of species were enumerated according to morphology and size (Pseudo-nizschia delicatissima and P. seriata groups). DA was detected over a nine-week period from July to October 2012 in the Lagoon, with a maximum concentration recorded in July (12.71?ng?DA?L?1). DA was positively correlated with the presence of P. seriata-group and P. delicatissima-group and was mostly occurred during P limitation period in seawater. No DA was found in mussels that were collected during the period of DA absence in seawater. Our results suggest that temperature, salinity, inorganic and organic nutrients were significant for the seasonal dynamics of P. seriata and P. delicatissima groups, but that the P limitation was the most driving factor for DA production in these areas. The relative influence of environmental factors should be further studied to better understand the recent surfacing of massive blooms of toxigenic Pseudo-nitzschia in SW Mediterranean coast. 相似文献
545.
实验发现,碘化二甲基胂(IDA)具有很好的色谱挥发性,在5%,10%SE-30柱上可得到较好的色谱峰。二甲基胂酸(DMA)碘化后生成碘化二甲基胂(IDA)。本文提出了新的碘化萃取体系:SnCl_2-KI(1moI/l)-HCl(6mol/l)-甲苯。该体系具有转化率高、干扰少的优点。实验还发现,经过阳离子交换树脂富集,有效地消除了低浓度时,DMA转化中或转化后的分解或吸附对测定的影响,从而提高了分析结果的准确度。 相似文献
546.
大红色基G生产中产生的废硫酸内含硫酸达50%,COD70g/L,难用常规的方法来处理。本文给出了用该废酸生产硫酸锌进而生产立德粉的方法,并用COD浓度作为硫酸锌质量的控制指标,氧化锌和了废硫酸后,有机会物从溶液中析了,COD的去除率达99%。残存的有机物用活性炭吸附法除去。控制ZnSO4溶液中COD≤60mg/L,可制得合格的B301立德粉。有杉本法使硫酸资源全部回收并且无废水排放。 相似文献
547.
铝离子与聚硅酸的相互作用 总被引:44,自引:5,他引:44
本文应用核磁共振技术及化学分析方法研究了铝离子与聚硅酸之间的相互作用情况;借助于微电泳技术测定了含铝离子的聚硅酸絮凝剂在不同pH值条件下水解沉淀物的表面ζ电位变化情况;借助于透射电镜手段及静置观察方法考察了铝离子含量对聚硅酸胶凝作用的影响。实验结果表明,聚硅酸对铝离子具有一定的螯合(络合)和吸附作用,但二者之间不存在定量的作用关系,而是聚硅酸对铝离子的作用量随着铝离子含量的增加而增加。铝离子影响聚硅酸的胶凝时间,适量的铝离子的存在可延长聚硅酸的胶凝时间。聚硅酸的存在影响铝离子在不同pH值下的水解沉淀物的ζ电位值,使得达到零电位状态时的pH值向低pH值方向移动。 相似文献
548.
三种典型渔药对大型溞(Daphnia magna)的急性毒性及其关键环境影响因子分析 总被引:1,自引:0,他引:1
测试了三种典型渔药三氯异氰尿酸(Trichloroisocyanuricacid,TCCA)、叔丁基对羟基茴香醚(Butylatedhydroxyanisole,BHA)、盐酸环丙沙星(Ciprofloxacinhydrochloride,CPFX)对大型(Daphniamagna)的急性毒性。结果表明,对于大型的毒性由大到小的顺序为:三氯异氰尿酸,叔丁基对羟基茴香醚,盐酸环丙沙星,48hLC50分别为0.19mg·L-1,3.15mg·L-1和135.15mg·L-1。通过三因素三水平正交试验分析了主要环境因子pH值、硬度、腐殖酸对三种渔药对大型毒性的影响,发现pH显著影响TCCA的毒性,硬度显著影响CPFX的毒性,而BHA毒性受环境因素影响不显著。 相似文献
549.
Summary. Geographic variations in the correspondence between diaspore phenotypes and disperser behavior are thought to determine the
evolution of plant-animal dispersal mutualisms. Helleborus foetidus is a widely distributed plant in Western Europe, which seeds bear a lipid rich elaiosome attracting ant dispersers. Laboratory
cross-tests were conducted to check the correspondence between diaspore phenotypes and ant preference in two localities of
the Iberian Peninsula, Caurel and Cazorla, separated by 750 km. Diaspores from Caurel were systematically preferred to those
from Cazorla by Formica lugubris (the major disperser at Caurel), and Aphaenogatser iberica and Camponotus cruentatus (both major dispersers at Cazorla). Further bioassays conducted on A. iberica only showed that differences in elaiosome traits were sufficient to explain ant preference. Separation of the lipid fractions
composing the elaiosome revealed that triglycerides, diglycerides and free fatty acids were all dominated by oleic acid. The
elaiosomes from Caurel contained relatively more free oleic acid but were less concentrated in linoleyl-containing triglycerides,
free palmitic acid and free linoleic acid than those from Cazorla. The three lipid fractions were attractive to ants but dummies
soaked with the free fatty acids extracted from Caurel were preferred to those from Cazorla. Taken together, these results
reinforce the idea that oleic acid is a major releaser of seed collection by ants and suggest that geographic variations in
free fatty acid composition affect the probability of diaspore removal by ants which in turn potentially determine plant demography. 相似文献
550.
低分子量有机酸对可变电荷土壤吸附铝的影响机制 总被引:3,自引:0,他引:3
通过吸附性铝的解吸实验研究了低分子量有机酸对三种可变电荷土壤(2种砖红壤和1种赤红壤)吸附铝的影响机制,结果表明,柠檬酸、苹果酸和酒石酸等带有3个及3个以上活性官能团的有机酸在低pH条件下可以通过形成土壤一有机酸一铝三元表面络合物和增加土壤的表面负电荷两种机制显著增加土壤对铝离子的吸附量,但以前一种影响机制为主。乳酸、水杨酸、草酸和丙二酸等带有2个活性官能团的有机酸仅通过改变土壤的表面负电荷影响铝的吸附。土壤氧化铁是土壤吸附有机酸的主要载体,当用化学方法将土壤中的氧化铁除去后,有机酸对铝吸附的影响变小。在pH5.0时有机酸主要通过形成可溶性有机铝络合物减小土壤对铝的吸附,但有机酸的存在增加了Al^3 在吸附性铝中所占的比例,导致铝的解吸率增加。土壤中大量氧化铁的存在使其即使在低pH下也能对铝离子发生专性吸附,导致吸附性铝的解吸率减小。 相似文献