Ambient gas/particle partitioning. 1. Sorption mechanisms of apolar, polar, and ionizable organic compounds

There remain several ambiguities in the literature regarding the dominating sorption mechanisms involved in gas/particle partitioning, particularly for polar and ionizable compounds. The various hypothetical mechanisms would depend differently on relative humidity (RH) and the presence of various aerosol components. Thus, in order to resolve these ambiguities, here we measured the RH-dependency of gas/particle partitioning constants, K(ip), for four diverse aerosol samples and a large set of chemicals covering apolar, polar, and ionizable organic compounds. In addition, we also removed the water-soluble components from two ambient particle samples to study how their presence influences sorption behavior. The measured K(ip) values collectively indicate that a dual-phase sorption mechanism is occurring, in which organic compounds partition into a RH-independent water-insoluble organic matter phase and additionally into a RH-dependent mixed-aqueous phase. All K(ip) values could be successfully fitted to a RH-dependent dual-phase sorption model. The trends in K(ip) data further support findings that the sorption behavior of ambient aerosol samples is different from raw mineral surfaces and soot.     

Bolus ingestion of white and green tea increases the concentration of several flavan‐3‐ols in plasma,but does not affect markers of oxidative stress in healthy non‐smokers

White tea (WT) is rich in flavan‐3‐ols as green tea (GT) and might provide health protective effects due to the strong antioxidant properties of flavan‐3‐ols. Since intervention studies with WT are lacking, we evaluated the effects of WT consumption on antioxidant status, antioxidant capacity and biomarkers of oxidative stress compared to water and GT. After an overnight fast, 70 healthy non‐smokers were randomized to consume 600 mL of WT, GT or water (control). Plasma (epi‐)catechin and epi(gallo)catechingallate, antioxidant capacity (Folin assay, trolox equivalent antioxidant capacity test), 8‐iso‐prostaglandin F_2α, ascorbic acid and uric acid were determined before and several times within 8 h after consumption. DNA strand breaks were measured in vivo and ex vivo (H₂O₂ stimulation) in leukocytes. Plasma flavan‐3‐ols significantly increased after WT and GT ingestion. Trolox equivalent antioxidant capacity was lower after 5 h in controls versus WT (p=0.031) and GT (p=0.005). Folin‐Ciocalteu reducing capacity, ascorbic and uric acid as well as markers of oxidative stress (8‐iso‐prostaglandin‐F_2α, DNA strand breaks) were not affected by the beverages. A short‐term increase of catechins does not change plasma antioxidant capacity in healthy subjects. Conclusions with respect to health protective effects of WT and GT on the basis of these biomarkers can, thus, not be drawn.     

Arsenic, cadmium, lead and mercury in meat, livers and kidneys of sheep slaughtered in The Netherlands

Summary The results obtained between 1981 and 1986 in a Dutch monitoring programme investigating the presence of arsenic, cadmium, lead and mercury in meat, livers and kidneys of sheep are presented. For the meat, livers and kidneys, the median values were 0.001, 0.003,and 0.007 mg/kg (fresh weight) for arsenic; 0.003, 0.054, and 0.098 mg/kg for cadmium; 0.04, 0.85, and 0.36 mg/kg for lead; and 0.001, 0.002, and 0.007 mg/kg for mercury. During the reported period, no clear trends were observed. The results are compared with the data from other countries. The mercury and arsenic concentrations in meat and organs may be regarded as low, but the levels of lead in livers are relatively high. The lead concentrations in livers showed seasonal fluctuations, the highest concentrations usually being found during the winter. Significant linear relationships were found between the concentrations in livers and kidneys for arsenic, cadmium and mercury. Tissue trace element levels were not related to the age of the investigated animals.

---

Arsen, Cadmium, Blei und Quecksilber in Fleisch, Leber und Niere von Schafen in den Niederlanden

Zusammenfassung Es wird über die Ergebnisse der Jahre zwischen 1981 und 1986 eines holländischen Überwachungsprogramms über das Vorkommen von Arsen, Cadmium, Blei und Quecksilber in Fleisch, Leber und Niere von Schafen berichtet. Für Fleisch, Leber und Niere lagen die ermittelten Medianwerte für Arsen bei 0,001 bzw. 0,003 und 0,007 mg/kg (bezogen auf Frischgewicht), für Cadmium bei 0,003 bzw. 0,054 und 0,098 mg/kg, für Blei bei 0,04 bzw. 0,85 und 0,36 mg/kg und für Quecksilber bei 0,001 bzw. 0,002 und 0,007 mg/kg. Die Gehalte zeigten keine signifikante Änderung während dieser Periode. Die Gehalte werden verglichen mit Angaben anderer Länder. Die Arsen- und Quecksilbergehalte unserer Untersuchung sind niedrig. Die Bleigehalte in Leber sind relativ hoch, sie zeigten Änderungen abhängig von der Jahreszeit. Die Höchstgehalte wurden gewöhnlich während der Winterzeit gefunden. Die Gehalte von Niere und Leber sind signifikant miteinander korreliert für die Elemente Arsen, Cadmium und Blei. Die Arsen-, Cadmium-, Blei- und Quecksilbergehalte von Fleisch und Organen sind nicht mit dem Alter der Tiere korreliert.

     

Combined application of stable carbon isotope analysis and specific metabolites determination for assessing in situ degradation of aromatic hydrocarbons in a tar oil-contaminated aquifer

To evaluate the intrinsic bioremediation potential in an anoxic tar oil-contaminated aquifer at a former gasworks site, groundwater samples were qualitatively and quantitatively analyzed by compound-specific isotope analysis (CSIA) and signature metabolites analysis (SMA). 13C/12C fractionation data revealed conclusive evidence for in situ biodegradation of benzene, toluene, o-xylene, m/p-xylene, naphthalene, and 1-methylnaphthalene. In laboratory growth studies, 13C/12C isotope enrichment factors for anaerobic degradation of naphthalene (epsilon = -1.1 +/- 0.4) and 2-methylnaphthalene (epsilon = -0.9 +/- 0.1) were determined with the sulfate-reducing enrichment culture N47, which was isolated from the investigated test site. On the basis of these and other laboratory-derived enrichment factors from the literature, in situ biodegradation could be quantified for toluene, o-xylene, m/p-xylene, and naphthalene. Stable carbon isotope fractionation in the field was also observed for ethylbenzene, 2-methylnaphthalene, and benzothiophene but without providing conclusive results. Further evidence for the in situ turnover of individual BTEX compounds was provided by the presence of acetophenone, o-toluic acid, and p-toluic acid, three intermediates in the anaerobic degradation of ethylbenzene, o-xylene, and p-xylene, respectively. A number of groundwater samples also contained naphthyl-2-methylsuccinic acid, a metabolite that is highly specific for the anaerobic degradation of 2-methylnaphthalene. Additional metabolites that provided evidence on the anaerobic in situ degradation of naphthalenes were 1-naphthoic acid, 2-naphthoic acid, 1,2,3,4-tetrahydronaphthoic acid, and 5,6,7,8-tetrahydronaphthoic acid. 2-Carboxybenzothiophene, 5-carboxybenzothiophene, a putative further carboxybenzothiophene isomer, and the reduced derivative dihydrocarboxybenzothiophene indicated the anaerobic conversion of the heterocyclic aromatic hydrocarbon benzothiophene. The combined application of CSIA and SMA, as two reliable and independent tools to collect direct evidence on intrinsic bioremediation, leads to a substantially improved evaluation of natural attenuation in situ.     

Design and performance of biofilters for the removal of alkylbenzene vapors

Three identical biofilters, run under the same conditions but inoculated with different mixed cultures, were fed a mixture of toluene, ethylbenzene, and o-xylene (TEX) gases. Inert porous perlite was used as support material, in contrast to the more conventional biofiltration systems where natural supports are used. Biodegradation started in all three biofilters a few hours after inoculation, without previous adaptation of the inocula to the toxic mixture. Despite acidification of the systems to pH values below 4·5, the elimination capacities reached were fully satisfactory. The best performing biofilter, in which bacteria were dominant, showed an elimination capacity of 70 g TEX m⁻³ h⁻¹ with a near complete removal of the mixture up to an influent concentration of 1200 mg TEX m⁻³ at a gas residence time of 57 s. Most of the ingoing carbon was recovered as carbon dioxide in the outgoing gas. In the other biofilters fungi dominated and performance was slightly worse. With single substrates, the elimination capacity was higher for toluene and ethylbenzene than for the TEX mixture, whereas o-xylene removal was slowest in all cases. Also when feeding the mixture to the biofilters, o-xylene was removed most slowly.     

Strukturanalytische Untersuchungen an Folgeprodukten aus Sulfonamiden. VIII. Zur Struktur der Reaktionsprodukte aus 1,1,3-trisubst. Thioharnstoffen und N-Tosyl-iminothiokohlensäuremethylester-chlorid

Structure-Analytical Investigations of Consecutive Products of Sulphonamides. VIII. About the Structure of Reaction Products from 1,1,3-Trisubst. Thioureas and N-Tosyl-iminothiocarbonic Acid Methylester Chlorides The structure of a variety of reaction products from 1,1,3-trisubstituted thioureas ( 1 a – e ) and N-tosyl-iminothiocarbonic acid methylester chlorides ( 2 ) is investigatigated with respect to whether a sequence  SO₂ NC S C (structure I ) or  SO₂ NC N C (structure I ) is form ed. The problem is solved by means of m.s. and i.r. spectra as well as the Feigl test. The results of these investigations show that structure I is formed.