Main particulate matter components in Saxony (Germany)

Aerosol filter samples have been collected nearby the industrialised basin of Leipzig in Saxony (Germany) at the research station Melpitz of the Institut für Troposphärenforschung e.V. (IfT). Time series (1992–1998) and a three year comparison (1995–1997) of two different aerosol filter sampling systems, the Sierra-Andersen-PM 10 high volume sampler (daily sample, PM 10 inlet) and the Rupprecht and Patashnik Co. Inc. Model Partisol 2000 (weekly sample, PM 10 and PM 2.5 inlet) are presented and discussed. The comparison of the different sampling systems and strategies yields small differences between the daily and weekly samples for mass and different ions, which may be influenced by sampling duration and flow rates. A general trend of change in aerosol composition was observed: Soot and Sulphate concentrations decreased whereas Nitrate and Ammonium concentrations increased. During summers the mass of coarse particles is higher than in other seasons. One reason could be found in the occurence of longer periods of dry ground surfaces enabling reemission of crustal and biological material. The time series have been integrated in a longer historical aerosol mass trend for Saxony and do show a good agreement. Since 1990 a significant downward trend in gravimetric mass concentration was found.     

Functional responses of juvenile herring and sprat in relation to different prey types

The relationship between particulate-feeding rates and prey concentrations (functional response) of juvenile herring and sprat (5–9 cm total length) was investigated in controlled feeding experiments monitored by an underwater camera system. A special tank system was developed allowing the regulation and quantification of low prey concentrations (1–160 L^?1). Non-evasive Artemia nauplii was used as prey to estimate the maximum biting rate of both predators. In contrast, Acartia tonsa with a high escape ability was used as a realistic prey type. Herring and sprat showed a type II functional response for both prey types. Nonlinear mixed effects model revealed no significant difference between the functional responses of both predators, except that herring showed significantly higher biting rates than sprat at A. tonsa concentrations below ~40 L^?1. For both predators feeding rates were significantly higher with Artemia nauplii than with A. tonsa. Video analysis indicated that sprat, unlike herring, is an obligate particulate-feeder.     

Validation of spectral gas radiation models under oxyfuel conditions. Part A: Gas cell experiments

Combustion of hydrocarbon fuels with pure oxygen results in a different flue gas composition as combustion with air. Standard CFD spectral gas radiation models for air combustion are out of their validity range. The series of three articles provides a common spectral basis for the validation of new developed models. In part A of the series gas cell transmissivity spectra in the spectral range of 2.4–5.4 μm of water vapor and carbon dioxide in the temperature range from 727 to 1500 ° C and at different concentrations were compared at a nominal resolution of 32 cm^?1 to line-by-line models from different databases, two statistical-narrow-band models and the exponential wide band model. The two statistical-narrow-band models EM2C and RADCAL showed a good agreement with a maximal band transmissivity deviation of 3%. The exponential-wide-band model showed a deviation of 6%. The new line-by-line database HITEMP2010 had the lowest band transmissivity deviation of 2.2% and was recommended as a reference model for the validation of simplified CFD models.     

Vertical profile of PCDD/Fs, dioxin-like PCBs, other PCBs, PAHs, chlorobenzenes, DDX, HCHs, organotin compounds and chlorinated ethers in dated sediment/soil cores from flood-plains of the river Elbe, Germany

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and other organic micropollutants were determined in dated sediment/soil cores collected from the flood-plain of the river Elbe near Pevestorf (PT), approximately 125 km upstream of Hamburg, and Heuckenlock (HL) in southeast of Hamburg. Concentrations of PCDD/Fs peaked sharply at PT in the 1950s and at HL at the end of the 1940s. Cluster analyses provide evidence that the region of Bitterfeld-Wolfen (about 350-400 km upstream of Hamburg) could be the source of the PCDD/F contamination existing in the cores PT and HL since the 1940s. Obviously it is caused by sediments of the river Elbe of a similar composition. Whereas the PCDD/Fs, HCHs (hexacyclohexane isomers), DDX (DDT, DDD, DDE), and tetrachlorinated ethers in PT and HL presumably originated predominantly from the Bitterfeld-Wolfen region, organotin compounds in HL and dichlorinated haloethers in HL during the 1940s and 1950s can probably largely be attributed to emissions from the Hamburg region. Although they are separated by a large distance, in both sediment cores PT and HL concentrations and composition patterns of most organic micropollutants analyzed widely match. Inductively it can be concluded that similar contaminations will be found in many of the river bank soils between the Bitterfeld-Wolfen region and Hamburg. Excavation of top soils may uncover highly contaminated materials. Since the dated sediment cores show the variation in contaminants in the Elbe sediments over a defined time period, it is possible to make an approximate assessment of the actual degree of contamination to be expected in areas where in previous decades contaminated dredged sediments from the Elbe and from the Port of Hamburg have been deposited on land and used for building plots or for agricultural purposes.