Decomposition of CCl4 and CHCl3 on gliding arc plasma

Introduction C hlorinated volatile organic com pounds(C V O C s) w ere released to the atm osphere as flue gases from various industrial processes. C hlorinated hydrocar- bons have been w idely accepted as solvents and chem ical interm ediates in the m an…     

Immissionsbelastungen im Umfeld des Flughafens München

Zusammenfassung  Die Immissionsbelastung im ?stlichen Umland des neuen Münchner Flughafens wurde im Zeitraum von 1992 bis 1995 mit Hilfe einer Reihe unterschiedlicher Messmethoden untersucht. Für die wirkungsbezogene Erfassung von Umwelteinflüssen wurden Bioindikatoren zur Bestimmung der PAK-Belastung und zur Quantifizierung der Photooxidantienbelastung eingesetzt. Darüber hinaus wurde der PAK-Gehalt des Oberbodens bestimmt. Die aktuelle Luftbelastungssituation wurde w?hrend photochemisch aktiver Wetterlagen im Sommer im Rahmen von 7 Intensivmesskampagnen untersucht. Die Bodenbelastung mit PAK liegt im Bereich der für l?ndliche Regionen typischen Hintergrundwerte mit den h?chsten Konzentrationen in der N?he stark befahrener Stra?en und weist keinen zeitlichen Trend auf. Auch der aktuelle PAK-Eintrag liegt an allen Standorten in einem für l?ndliche Regionen in Bayern typischen Bereich. Als Hauptemittent wird im Sommer der Kfz-Verkehr identifiziert, w?hrend die deutlich erh?hte Belastung im Winter auf den Hausbrand zurückgeführt werden kann. Die Photooxidantien-belastung zeigt im Flughafenumland keine ausgepr?gten Unterschiede, sie ist an den durch Stra?enverkehr beeinflussten Standorten jedoch am geringsten. Die Konzentrationen leicht flüchtiger Kohlenwasserstoffe sind an einer verkehrsreichen Stra?enkreuzung in Erding deutlich h?her als im l?ndlichen Flughafenumland. Sie zeigen ausgepr?gte Tagesg?nge, die u.a. auf den luftchemischen Abbau zurückzuführen sind. Die Hydroperoxide als sekund?re Luftschadstoffe weisen einen gegens?tzlichen Verlauf auf, der dem des Ozons mit nachmitt?glichem Maximum ?hnelt. Online-First: 23. August 2000     

Retention behavior of hydrophobic organic chemicals as a function of temperature in soil leaching column chromatography

To study the transport mechanism of hydrophobic organic chemicals (HOCs) and the energy change in soil/solvent system, a soil leaching column chromatographic (SLCC) experiment at an environmental temperature range of 20-40 degrees C was carried out, which utilized a reference soil (SP 14696) packed column and a methanol-water (1:4 by volume ratio) eluent. The transport process quickens with the increase of column temperature. The ratio of retention factors at 30 and 40 degrees C (k'30/k'40) ranged from 1.08 to 1.36. The lower enthalpy change of the solute transfer in SLCC (from eluent to soil) than in conventional reversed-phase liquid chromatography (e.g., from eluent to C18) is consistent with the hypothesis that HOCs were dominantly and physically partitioned between solvent and soil. The results were also verified by the linear solvation energy relationships analysis. The chief factor controlling the retention was found to be the solute solvophobic partition, and the second important factor was the solute hydrogen-bond basicity, while the least important factors were the solute polarizability-dipolarity and hydrogen-bond acidity. With the increase of temperature, the contributions of the solute solvophobic partition and hydrogen-bond basicity gradually decrease, and the latter decreases faster than the former.     

Effect of linear alkylbenzene sulphonate (LAS) on the mineralization, metabolism and uptake of 14C-phenanthrene in a model ecosystem (water-lava-plant-air)

The aim of this work was to evaluate the effect of linear alkylbenzene sulfonate (LAS, 200 mg l(-1)) on the fate of phenanthrene in a model ecosystem "water-lava-hydrophytes-air". The experiments were conducted using two closed cultivation chamber systems. Rushes (Juncus effesus) were selected as a representative hydrophyte. Five hundred micrograms per liter of phenanthrene in a culture solution containing a 14C-activity of 75 microCi per chamber was applied (i) to investigate the degradation of the labeled test substance and the transfer processes within the system; (ii) to determine the mass-balance possible and (iii) to detect the occurrence of volatile test substances, their volatile metabolites and the degradation end-product CO2 in the gas phase. Most of the applied 14C-activity was found in the plant (41-45%), in which approximately 95% was associated with plant roots and approximately 5% with shoots. The 14C-activity recovered in the form of VOCs and CO2 was measured in lava (18-29%, 8-11%), and in the culture solution (10-14% and 1%), respectively. Majority of the applied 14C-activity existed in two forms, i.e. (1) polar metabolites (26%), of which 91% were found in plant roots, and (2) un-extractable residues (23%), most of which were in plant roots (40%) and bounded to lava (58%). The presence of LAS significantly increased the volatilization of phenanthrene and its metabolites, inhibited its mineralization and decreased the level of 14C-activity in lava. Moreover, LAS reduced the phenanthrene level in plant roots.     

用废砖制作利废型轻质墙体材料试验研究

采用正交试验的方法,研究了废砖、废聚苯粒及天然砂的不同配比对利废型轻质墙材性能的影响,配制出了抗压强度5.0 MPa以上,表观密度1 100 kg/m3以下,导热系数0.2 W(/m.K)以下,50次冻循环强度损失率20%以下,质量损失率5%以下的利废型轻质墙材,并讨论了骨料的不同配比与性能的关系。     

Verteilungskoeffizienten chlorierter Kohlenwasserstoffe zwischen Muskulatur und Leber bei Fischen

Measured partition coefficients (KL_M/L) related to lipid-concentrations between the muscle (C_ML) and liver (C_LL) tissue of two fish species (Abramis brama, Zoarces viviparus) exhibit nominal values of unity according the relationship KL_M/L=C_ML/C_LL=1 for persistent compounds such as highly chlorinated PCB and values above one for degradable compounds for example chlorinated cyclohexanes or DDT. The corresponding theory is presented. The relationship holds for samples for single fish as well as for pooled samples.