Spatial and temporal trends of perfluorinated compounds in Beluga Whales (Delphinapterus leucas) from Alaska

Wildlife from remote locations have been shown to bioaccumulate perfluorinated compounds (PFCs) in their tissues. Twelve PFCs, consisting of perfluorinated carboxylic (PFCA) and sulfonic (PFSA) acids as well as the perfluorooctane sulfonate (PFOS) precursor perfluorooctane sulfonamide (PFOSA), were measured in livers of 68 beluga whales (Delphinapterus leucas) collected from two subpopulations, Cook Inlet and eastern Chukchi Sea, in Alaska between 1989 and 2006. PFOS and PFOSA were the dominant compounds measured in both beluga stock populations, with overall median concentrations of 10.8 ng/g and 22.8 ng/g, respectively. Long-chain perfluorocarboxylates, PFCAs (9 to 14 carbons), were detected in more than 80% of the samples. Perfluoroundecanoic acid (PFUnA) and perfluorotridecanoic acid (PFTriA) made up a large percentage of the PFCAs measured with median concentrations of 8.49 ng/g and 4.38 ng/g, respectively. To compare differences in location, year, sex, and length, backward stepwise multiple regression models of the individual and total PFC concentrations were used. Spatially, the Cook Inlet belugas had higher concentrations of most PFCAs and PFOS (p < 0.05); however, these belugas had a lower median concentration of PFOSA when compared to belugas from the eastern Chukchi Sea (p < 0.05). Temporal trends indicated most PFCAs, PFHxS, PFOS, and PFOSA concentrations increased from 1989 to 2006 (p < 0.05). Males had significantly higher concentrations of PFTriA, ΣPFCA, and PFOS (p < 0.05). Perfluorononanic acid (PFNA) and PFOS showed a significant decrease in concentration with increasing animal length (p < 0.05). These observations suggest the accumulation of PFCs in belugas is influenced by year, location, sex, and length.     

Concentration and bioaccumulation of dechlorane compounds in coastal environment of northern China

Dechloranes, including Dechlorane Plus (DP), Mirex (Dechlorane), Dechlorane 602 (Dec 602), Dechlorane 603 (Dec 603), and Dechlorane 604 (Dec 604), were determined using GC-MSD for water, sediment and oyster samples collected at 15 sampling sites near the Bohai and Huanghai Sea shore area of northern China in 2008. DP and Mirex were detected in most water, sediment, and oyster samples, which indicated widespread distribution of these two compounds. The mean concentrations in water, sediment and oyster samples, respectively, were 1.8 ng/L, 2.9 ng/g dry weight (dw) and 4.1 ng/g wet weight (ww) for total DP, and 0.29 ng/L, 0.90 ng/g dw, and 2.0 ng/g ww for Mirex. Dec 602 and Dec 603 were not detected in water but in small portions of the sediment and oyster samples, showing a low level of contamination by these two chemicals in the region. Strong and significant correlations were found between total DP and Mirex concentrations in water, sediment and oyster samples, probably suggesting similar local sources of these two chemicals. Dec 604 was not found in any samples. The biota-sediment accumulation factor (BSAF) of DP, Mirex, and Dec 602 declined along with the increase of their logarithm of octanol-water partition coefficients (log Kow), possibly indicating that compounds with lower log Kow (like Mirex and Dec 602) accumulated more readily in biota. The mean fractional abundance of syn-DP (fsyn) was 0.34 in water samples, a value lower than that in Chinese commercial mixture (0.41), while the mean fsyn for surface sediment (0.44) and oyster (0.45) samples were higher than technical values. Enrichment of syn-DP in oyster was in agreement with previously reported findings in Great Lakes fish. Enrichment of syn-DP in marine surface sediments, however, is contrary to data reported for fresh water sediments. To our knowledge this is the first report of Dec 602, Dec 603, and Dec 604 in a marine environment and also the first report of Dechloranes in marine biota.     

Mechanical damage to Gram-negative bacteria by surface plating with the Drigalski-spatula technique

Colony counting by spreading bacterial suspensions on plating media by various techniques is of general concern. Comparative studies between hand plating (Drigalski-spatula technique) for different time intervals and spiral plating resulted in significant differences in colony counts. Lower counts of Gram-negative bacteria were obtained by using hand plating for more than 10 s, compared with short time hand plating (5 s) or spiral plating. Colony counting of Gram-positive bacteria showed no differences between both techniques. Further characterisation of Escherichia coli cells spread with the Drigalski-spatula technique by electron microscopy revealed a large number of damaged cells compared to control samples. The data clearly shows that the mechanical forces during hand plating are sufficient to damage E. coli cells.     

Wachstum der Weltbevölkerung und nachhaltige Tragfähigkeit

Das globale Wachstum der Weltbev?lkerung und die Folgen der zunehmenden Verst?dterung lassen angesichts der weltweiten Verbreitung von Armut und Unterern?hrung die Frage nach den künftigen Grenzen der agraren Tragf?higkeit der Erde aufkommen. Das von den UN-Modellrechnungen, die in der vorliegenden Ver?ffentlichung im überblick vorgestellt werden, vorausberechnete weitere Bev?lkerungswachstum und der Fl?chenverbrauch durch die zunehmende Verst?dterung und Industrialisierung lassen die pro Kopf der Weltbev?lkerung für die Nahrungsmittelproduktion verfügbare Anbaufl?che bis zur Jahrhundertmitte deutlich schrumpfen. Hinzu kommen die gegenw?rtig nur schwer absehbaren Auswirkungen von Bodendegradation und Klimawandel auf die Produktion von Nahrungsmitteln. Ob es hinsichtlich der Tragf?higkeit eine mehr als theoretische Grenze für die Zahl an Menschen gibt, die auf der Erde unter optimalen Bedingungen ern?hrt werden k?nnen, ist umstritten. Trotz eines Rückgangs an agrarer Nutzfl?che pro Kopf geht die FAO in ihrer Prognose aktuell davon aus, dass das globale Angebot an Kalorien pro Kopf der Weltbev?lkerung bis 2030 gesteigert und die Anzahl von Unterern?hrung betroffener Menschen deutlich reduziert werden kann. Unter dem Aspekt der Nachhaltigkeit ist die Produktion von Nahrungsmitteln aber vor allem im Kontext der aktuellen Produktionsbedingungen und der Konkurrenz zu anderen Konsumbereichen zu betrachten und diesbezüglich ist nach Berechnungen des Global Footprint Networks, die hier herangezogen werden, bereits in den 1980er Jahren die Biokapazit?t der Erde für eine nachhaltige Entwicklung überschritten worden. Setzt sich die derzeitige Entwicklung fort, wird unter Einbeziehung des von der UN angenommenen globalen Bev?lkerungswachstums die Biokapazit?t der Erde bis 2050 um mehr als das Doppelte überschritten werden. Eingegangen: 9. Januar 2009; angenommen: 16. Januar 2009 http://www.bib-demographie.de     

Kuppelproduktion und Umweltpolitik: Eine Fallstudie zur Chlorchemie und zur Schwefelsäureindustrie

Joint Production and Environmental Policy: A Case Study for the Chlorine and Sulphuric Acid Industry The chemical industry is a key sector of industrialised economy. Thus, environmental policy with a focus on the chemical industry is likely to affect the economy as a whole. In this article we show, that environmental regulation of the chemical industry has major consequences for other production sectors. Two major problem areas of the chemical industry are considered: the chlorine industry and the sulphur industry. While the chlorine industry can cope with environmental legislation by process and product innovation without a substantial impact on other sectors, this is not the case with the sulphur industry. The production of its key product, sulphuric acid, utilises joint products of other sectors as inputs. The chemical industry offers these sectors the possibility to dispose of their unwanted by-products. Environmental policy, directed towards a reduction of sulphuric acid is likely to cause a waste disposal problem in sectors which manufacture sulphur or sulphur dioxide as by-products. Solving environmental problems within the chemical industry therefore creates new problems in other sectors.     

Mechanical and thermal properties of UV-curable polyurethane and polyurea acrylates

Soft-segment molecular weight, soft-segment crystallization, hard-segment-type, and reactive diluent level were examined in urea and urethane acrylates. Increasing soft-segment molecular weight led to a decreased tensile modulus, increased strength, and increased elongation at break. Soft-segment crystallization increased the modulus below the melting temperature, but decreased the modulus above the melting temperature because crystallization interfered with cross-linking. Materials with hard segments that allowed for greater phase separation showed a higher modulus, higher ultimate stress, and higher ultimate elongation. Materials with reactive diluents 2-hydroxyethyl methacrylate (HEMA) and N-vinyl pyrrolidinone (NVP) showed qualitatively different behavior. HEMA caused the modulus and strength to increase with little effect on elongation up to concentrations of 50 wt %; at higher concentrations, the elongation decreased. NVP also increased the modulus and strength; however, at 40 wt % NVP, ultimate elongation increased in a well-phaseseparated system and decreased in a poorly phase-separated system. In tensile tests, samples with 40% NVP also showed substantial sample necking and drawing. © 1993 John Wiley & Sons, Inc.