Reactive transport modelling of biogeochemical processes and carbon isotope geochemistry inside a landfill leachate plume

The biogeochemical processes governing leachate attenuation inside a landfill leachate plume (Banisveld, the Netherlands) were revealed and quantified using the 1D reactive transport model PHREEQC-2. Biodegradation of dissolved organic carbon (DOC) was simulated assuming first-order oxidation of two DOC fractions with different reactivity, and was coupled to reductive dissolution of iron oxide. The following secondary geochemical processes were required in the model to match observations: kinetic precipitation of calcite and siderite, cation exchange, proton buffering and degassing. Rate constants for DOC oxidation and carbonate mineral precipitation were determined, and other model parameters were optimized using the nonlinear optimization program PEST by means of matching hydrochemical observations closely (pH, DIC, DOC, Na, K, Ca, Mg, NH4, Fe(II), SO4, Cl, CH4, saturation index of calcite and siderite). The modelling demonstrated the relevance and impact of various secondary geochemical processes on leachate plume evolution. Concomitant precipitation of siderite masked the act of iron reduction. Cation exchange resulted in release of Fe(II) from the pristine anaerobic aquifer to the leachate. Degassing, triggered by elevated CO2 pressures caused by carbonate precipitation and proton buffering at the front of the plume, explained the observed downstream decrease in methane concentration. Simulation of the carbon isotope geochemistry independently supported the proposed reaction network.     

A chromosome 21-specific cosmid cocktail for the detection of chromosome 21 aberrations in interphase nuclei

Fluorescent in situ hybridization (FISH) with a 21q11-specific probe (CB21c1) consisting of three non-overlapping cosmids has been applied to interphase amniocytes of pregnancies at increased risk for fetal aneuploidy (N = 78) and to interphase lymphocytes, cultured and uncultured, of patients referred for Down syndrome (N = 19 and 28, respectively). In the uncultured amniocytes, six chromosome aberrations were detected: three cases of trisomy 21, a triploidy, a de novo 46,XX,t(21q21q), and a mosaic 46,XY/47,XY,+dic(21)(q11)/48,XY,+dic(21)(q11), +del(21)(q11). In 15 cultured and 20 uncultured blood samples, FISH correctly diagnosed trisomy 21 (full or mosaic) at the interphase level, which was confirmed in all cases by subsequent karyotyping. Because of specific and strong signals in interphase nuclei, CB21c1 appears to be a useful tool for the rapid detection of chromosome 21 abnormalities.     

46,XY,dup(10q) in direct CVS preparation and mosaic 48,XXXY,dup(10q) in CVS long-term culture and fetal tissue

Chorionic villus sampling (CVS) was performed on a 40-year-old woman at 9 1/2 menstrual weeks because of advanced maternal age. The direct preparation showed 46,XY,dup(10)(q11.2q23.2). CVS long-term culture and fetal tissue revealed a rare additional abnormality: 48,XXXY,dup(10)(q11.2q23.2). This abnormality represented the major cell line (>85 per cent in 691 cells) in an (XY)/XXY/XXXY/(XXXXY) mosaic (all cell lines presumably bearing the dup(10q); the presence of XY and XXXXY cell lines is uncertain). To our knowledge, this is the first report of trisomy 10q11-q23 and of prenatally detected 48,XXXY in chorionic villi. The mosaic could have resulted from early post-zygotic non-disjunctions in a 46,XY,dup(10q) or 47,XXY,dup(10q) zygote. The results from DNA studies of four polymorphisms, mapped to Xp and Xq, support this theory. The literature on prenatally detected cases with sex chromosome tetrasomy and pentasomy and those with additional autosomal abnormalities is reviewed. The reported case underlines the problem of false-negative findings when only direct CVS preparations are karyotyped.     

多核聚合形态Al30混凝控制水中腐殖酸与残留铝的研究

制备了优势形态为Al30的聚合铝PAC-Al30,与优势形态为Al13的常用聚合铝PAC-Al13及AlCl3作对比实验,考察了不同铝系混凝剂强化混凝控制水中腐殖酸(Humic Acid,HA)和残留铝的差异.结果表明,PAC-Al30具有足够的稳定性,与PAC-Al13和AlCl3相比,PAC-Al30可以更好地控制出水腐殖酸和残留铝浓度,且以碱化度B为2.4的PAC-Al30效果最好.PAC-Al30和PAC-Al13比AlCl3有更宽的有效投量范围,可以提高实际应用中的稳定性.Ca2 和高岭土的存在均有利于PAC-Al30混凝去除HA.低温对PAC-Al30混凝去除HA有不利影响.研究表明,Al30是一种可用于控制水中腐殖酸和残留铝的新型混凝/絮凝活性成分.     

Oil spills on other commodities

This paper examines the effect of crude oil prices on the prices of 35 internationally traded primary commodities for the 1960–2005 period. It finds that the pass-through of crude oil price changes to the overall non-energy commodity index is 0.16. At a more disaggregated level, the fertilizer index had the highest pass-through (0.33), followed by agriculture (0.17), and metals (0.11). The prices of precious metals also exhibited a strong response to crude oil price. In terms of individual commodities, the estimates of the food group exhibited remarkable similarity while those of raw materials and metals gave a mixed picture. The implication is that if crude oil prices remain high for some time, as most analysts expect, then the recent commodity price boom is likely to last much longer than earlier booms, at least for food commodities. The other commodities, however, are likely to follow diverging paths. On the methodological side, the results show that price indices, while providing useful summary statistics, they need to be supplemented by individual commodity analysis.     

C?sium-137 in B?den saarl?ndischer Wald?kosysteme

Zusammenfassung Ziel und Schwerpunkte  Um das Verhalten des künstlichen Radionuklids¹³⁷Cs im Landschaftshaushalt der Saar-Lor-Lux Region zu klaren, wurdend die r?umliche Verteilung sowie das deszendente Migrationsverhalten und die Tiefenfunktionen des Radioisotops in den wichtigsten Bodensubstraten saarl?ndischer Wald?kosysteme untersucht. Ergebnisse  Demnach finden sich die h?chsten¹³⁷Cs-Aktivit?ten im Norden des Landes, w?hrend die Gebiete im Süden und Südosten deutlich geringere Konzentrationen aufweisen. Es konnten deszendente Migrationsraten zwischen 0,25 cm/a und 1,0 cm/a festgestellt werden. Durchschnittlich treten die h?chsten Migrationsraten in den tonig-schluffigen Substraten des Muschelkalks auf (0,66 cm/a), gefolgt von den lehmig ausgepr?gten Substraten des Unterrotliegenden (0,53 cm/a) und den sandigen Substraten des Buntsandsteins (0,41 cm/a). In den tonarmen Bodensubstraten des Unterrotliegenden und des Buntsandsteins lassen sich 90–95% der Aktivit?ten in den oberen 10 cm der humusreichen Oberb?den nachweisen, wohingegen in den tonreichen Substraten des Muschelkalks bis zur gleichen Tiefe nur etwa 70–76% zu finden sind. Schlussfolgerungen  Mit einem Abnehmen der als Leitbahnen fungierenden Prim?r-und Sekund?rporen in zunehmender Tiefe ist künftig mit einer deutlichen Reduzierung der Verlagerungsgeschwindigkeit von¹³⁷Cs in den Substraten des Muschelkalks zu rechnen. Insbesondere bei geringm?chtigen B?den auf kluftreichem Ausgangsgestein impliziert die maximale Eindringtiefe des Isorops von 40 cm in den Unterboden jedoch eine m?gliche Kontamination des oberfl?chennahen Grundwassers, ebenso wie an Standorten mit hohem Grundwasserstand. Ausblick  Aufgrund der hier vorgestellten Ergebnisse wurde ein¹³⁷Cs-Monitoring in das Boden-Dauerbeobachtungsprogramm des Landesamts für Umweltschutz des Saarlandes aufgenommen Online-First: 25. April 2000     

不同铝形态去除水中腐殖酸的混凝特性

制备了碱化度为2.4、以Al13,为主要成分的聚合铝PAC-All13和碱化度为2.4、以Al30为主要成分的高聚聚合铝PAC-Al30.采用烧杯混凝实验,通过絮体颗粒生长、电中和能力、pH和混凝剂投量对混凝效果的影响,比较了PAC-Al30、PAC-Al13,和AIC3,混凝去除水中腐殖酸的行为,并考察了水中残留铝的含量.实验结果表明,3种混凝剂的絮体形成能力由强到弱为PAC-Al30>PAC-Al13>AlCl3.与AlCl3相比, PAC-Al13和PAC-Al30的适用pH范围更宽,为5.0～8.0.PAC-Al30和PAC-Al13,的电中和能力差别不明显;由于更强的吸附和架桥作用,在低投量下PAC-Al30表现出更好的混凝效果,而且PAC-Al30比AlCl3和PAC-Al13有更宽的有效投量范围,为0.08～0.64mmol/L.对于腐殖酸含量为10m/L的水样,在pH为7.0,投量为0.16mmol/L下, PAC-Al30对腐殖酸去除率达到98.5%,此时出水残留铝浓度为0.066mg/L.结果证实Al30是可用于水中腐殖酸去除的一种新型的混凝/絮凝活性成.     

生态系统转换区土壤有机质动力学特征的δ^13C方法研究

对土壤有机质的动力学过程的研究是评价区域土壤质量、合理开发利用土壤以及全球碳循环一气候交化研究的基础性工作。系统分析了生态系统转换区土壤有机质动力学特征的δ^13C方法研究的理论基础和应用现状,包括影响土壤有机质δ^13C值的各种内外因素;土壤有机质不同化学组成、不同粒径组分、不同比重组分的δ^13C特征值域;土壤微生...     

Steel consumption and economic growth in Korea: Long-term and short-term evidence

This paper examines the long-term and short-term causal relationships between steel consumption and economic activity in Korea between 1975 and 2008 using vector error correction and vector autoregression models. This study disaggregates steel products and steel-consuming industries because the consumption of a specific steel product is closely linked to the output of the corresponding industry. This approach can provide a clear and reliable causal relationship between variable pairs. The results show that total steel consumption and GDP have a long-term equilibrium relationship, running from GDP to total steel consumption. However, a long-term bi-directional causal relationship exists between flat products consumption and the manufacturing GDP. Flat products consumption also demonstrates the long-term relationships between steel-consuming industries, such as automobile, shipbuilding, and fabricated metal product, but causal directions are mixed, depending on variable pairs. These results imply that the reciprocal growth between these industries has contributed to the robust competitiveness of Korean manufacturing. Because Korea has maintained its export-oriented industrial policy based on manufacturing, the steel and steel-consuming industries are expected to play a significant role in economic growth far into the future.