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We report a centennial-scale warming event between 8600 and 8400 cal BP from Amery Oasis, East Antarctica, that is documented by the geochemical record in a lacustrine sediment sequence. The organic carbon content, the C/S ratio, and the sedimentation rate in this core have distinctly elevated values around 8500 y ago reflecting relatively warm and ice-free conditions that led to well-ventilated conditions in the lake and considerable sedimentation of both autochthonous and allochthonous organic matter on the lake bottom. This abrupt warming event occurred concurrently with reported warm climatic conditions in the Southern Ocean while the climate in central East Antarctic remained cold. The comparison of the spatial and temporal variability of warm climatic periods documented in various terrestrial, marine, and glacial archives from East Antarctica elucidates the uniqueness of the centennial-scale warming event in the Amery Oasis. We also discuss a possible correlation of the Amery warming event with the abrupt climatic deterioration around 8200 cal BP on the Northern Hemisphere. © 2007 Elsevier Ltd. All rights reserved.

In this review, we compile the evidence of lake and isolation basin sediments for the chronology of the last deglaciation along the coastal parts of eastern Greenland between 70°N and 83°N. Radiocarbon dates of remains of freshwater plants and bulk organic carbon extracted from lacustrine sediments suggest that the present day ice-free parts of eastern Greenland were not deglaciated prior to the early Holocene. Older dates do exist but must be used with caution due to possible contamination with old carbon. However, many inland locations in eastern North and central East Greenland became ice-free distinctly later between 10,000 and 7500 cal yr BP, depending on their relative position to the ice margin. This compilation confirms former suggestions that hitherto no secure Late glacial lacustrine sediments have been found in the ice-free parts of eastern Greenland. Late glacial sediments are only known from lakes in southern Greenland and from few marine locations off eastern Greenland. The here summarized lake sediment evidence for the last deglaciation supports the results of an earlier compilation of dates from marine shells. © 2007 Elsevier Ltd. All rights reserved.

Geochemical studies on Upper Carboniferous marine bands showed that marked enrichment in redox-sensitive trace elements (uranium (U), vanadium (V), molybdenum (Mo)) mostly occur if they contain Goniatites. Goniatites indicate deposition in relatively distal and deep marine environments. In contrast, Westphalian marine bands found in the Netherlands predominantly show a Lingula facies, indicating deposition in a nearshore environment. These Lingula marine bands are mostly lacking significant trace element enrichments. The aim of this paper is to explain the mechanisms causing the differences in geochemical characteristics between distal (Goniatites facies) and proximal (Lingula facies) marine bands. Geochemical analyses (total organic carbon (TOC), sulfur (S), major and trace elements) were carried out on a selection of these marine bands. Furthermore, a comparison was made with some lacustrine bands which broadly show the same sedimentary development as the Lingula marine bands. The results show that the Lingula marine bands, in contrast to the Goniatites and lacustrine bands, are characterised by low organic carbon contents (1 - 2 wt.%). A relatively high input of siliciclastics probably prevented the accumulation of organic-rich layers (dilution effect). In turn, low organic carbon contents most likely prevented the effective scavenging of trace elements. Although the lacustrine bands are characterised by high TOC contents, here the limited availability of trace elements in fresh water forms the best explanation for low trace metal enrichments. Since marine bands form stratigraphicalty important horizons in the Upper Carboniferous, many attempts have been made to recognise marine bands using well logs (gamma-ray). The results from this study show that using gamma-ray devices (detecting U-enrichments), only marine bands in a Goniatites facies are clearly recognised while Lingula marine bands are not detected.

Empirical relations between aerosol mass concentrations and Ångström parameters α were derived from simultaneous optical and chemical measurements on the Baltic in March 1998. The relations apply to mass concentrations of sea salt aerosol (SSA), black carbon (BC) and organic carbon (OC), expressed in terms of their ratio to the total particulate matter (TPM). Using these relations to calculate the mass concentrations of these aerosol components for a different season or a different area, yields favorable results. The relations were obtained and verified for Ångström parameters 0.2 ≤ α ≥ 1.43.

The European Committee for Standardisation (CEN) Technical Committee 264 'Air Quality' has recently produced a standard method for the measurements of organic carbon and elemental carbon in PM2.5 within its working group 35 in response to the requirements of European Directive 2008/50/EC. It is expected that this method will be used in future by all Member States making measurements of the carbonaceous content of PM2.5. This paper details the results of a laboratory and field measurement campaign and the statistical analysis performed to validate the standard method, assess its uncertainty and define its working range to provide clarity and confidence in the underpinning science for future users of the method. The statistical analysis showed that the expanded combined uncertainty for transmittance protocol measurements of OC, EC and TC is expected to be below 25%, at the 95% level of confidence, above filter loadings of 2 μg cm-2. An estimation of the detection limit of the method for total carbon was 2 μg cm-2. As a result of the laboratory and field measurement campaign the EUSAAR2 transmittance measurement protocol was chosen as the basis of the standard method EN 16909:2017. © 2017 The Royal Society of Chemistry. Chemicals/CAS: carbon, 7440-44-0

Radiocarbon analysis is a widely-used tool for source apportionment of aerosol particles. One of the big challenges of this method, addressed in this work, is to isolate elemental carbon (EC) for 14C analysis. In the first part of the study, we validate a two-step method (2stepCIO) to separate total carbon (TC) into organic carbon (OC) and EC against the EUSAAR_2 thermal-optical method regarding the recovered carbon concentrations. The 2stepCIO method is based on the combustion of OC in pure oxygen at two different temperature steps to isolate EC. It is normally used with a custom-built aerosol combustion system (ACS), but in this project, it was also implemented as a thermal protocol on a Sunset OC-EC analyzer. Results for the recovered EC mass concentration showed poor agreement between the 2stepCIO method on the ACS system and on the Sunset analyzer. This indicates that the EC recovery is sensitive not only to the temperature steps, but also to instrument-specific parameters, such as heating rates. We also found that the EUSAAR_2 protocol itself can underestimate the EC concentration on untreated samples compared to water-extracted samples. This is especially so for highly loaded filters, which are typical for 14C analysis. For untreated samples, the EC concentration on long-term filter samples (two to five days sampling time) was 20-45% lower than the sum of EC found on the corresponding 24-h filter samples. For water-extracted filter samples, there was no significant difference between long-term and the sum of daily filter samples. In the second part of this study, the 14C was measured on EC isolated by the 2stepCIO method and compared to methods from two other laboratories. The different methods agree well within their uncertainty estimates. © 2017 by the authors.

Adhesion of three marine bacterial strains, i.e. Marinobacter hydrocarbonoclasticus, Psychrobacter sp. and Halomonas pacifica with different cell surface hydrophobicities was measured on glass in a stagnation point flow chamber. Prior to bacterial adhesion, the glass surface was conditioned for 1 h with natural seawater collected at different seasons in order to determine the effect of seawater composition on the conditioning film and bacterial adhesion to it. The presence of a conditioning film was demonstrated by an increase in water contact angle from 15° on bare glass to 50° on the conditioned glass, concurrent with an increase in the amount of adsorbed organic carbon and nitrogen, as measured by X-ray photoelectron spectroscopy. Multiple linear regression analysis on initial deposition rates, with as explanatory variables the temperature, salinity, pH and concentration of dissolved organic carbon (DOC) of the seawater at the time of collection, showed that the concentration of DOC was most strongly associated with the initial deposition rates of the three strains. Initial deposition rates of the two most hydrophilic strains to a conditioning film, increased with the concentration of DOC in the seawater, whereas the initial deposition rate of the most hydrophobic strain decreased with an increasing concentration of DOC.

An integrated approach has been developed for the multi-component analysis of indoor PM2.5 collected onto the same quartz fiber filter (QFF) by using an innovative combination of techniques such as inductively coupled sector field plasma mass spectrometry (ICP-SF-MS) with vapor-phase microwave-assisted aqua regia or sonication-assisted water extraction, ion chromatography, thermal-optical transmittance as well as high performance liquid chromatography and enzyme-linked 5,5'-dithio-bis(2-nitrobenzoic acid) assay for the determination of elemental composition, major inorganic ions, elemental/organic carbon (EC/OC) as well as oxidative potential (OP) through ascorbate (AA) and reduced glutathione (GSH) depletion, respectively. The low mass of PM2.5 collectable indoors, the elemental blank values of the QFFs and the sample volume/acidity requirements of the ICP-SF-MS represented a challenge for elemental determination. Finally, this approach was successfully applied for determination of 15 elements (Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Mo, Cd, Sn and Pb) at the ngm-3 level in more than two-thirds of indoor PM2.5 (n=25) collected in mechanically ventilated offices within the European Union project OFFICAIR at increased sampling flow rates (0.6m3h-1-2.3m3h-1) and sampling time (cca. 100h) in the acidic/aqueous extracts. The concentration of Cl-, NO3 -, SO4 2-, Na+, NH4 +, K+, Ca2+, Mg2+, OC and EC was at the μgm-3 level in the aqueous extracts. This new approach aiming at the comprehensive characterization of low mass indoor PM2.5 samples allowed assessment of OPAA and OPGSH in all samples. The PM2.5 critical sample mass to achieve elemental determination was approximately 400μg.

Sources of elemental carbon (EC) and organic carbon (OC) in atmospheric aerosols (carbonaceous aerosols) were investigated by collection of weekly aerosol filter samples at six background sites in Northern Europe (Birkenes, Norway; Vavihill, Sweden; Risoe, Denmark; Cabauw and Rotterdam in The Netherlands; Melpitz, Germany) during winter 2013. Analysis of 14C and a set of molecular tracers were used to constrain the sources of EC and OC. During the four-week campaign, most sites (in particular those in Germany and The Netherlands) were affected by an episode during the first two weeks with high concentrations of aerosol, as continental air masses were transported westward. The analysis results showed a clear, increasing north to south gradient for most molecular tracers. Total carbon (TC = OC + EC) at Birkenes showed an average concentration of 0.5 ± 0.3 μg C m−3, whereas the average concentration at Melpitz was 6.0 ± 4.3 μg C m−3. One weekly mean TC concentration as high as 11 μg C m−3 was observed at Melpitz. Average levoglucosan concentrations varied by an order of magnitude from 25 ± 13 ng m−3 (Birkenes) to 249 ± 13 ng m−3 (Melpitz), while concentrations of tracers of fungal spores (arabitol and mannitol) and vegetative debris (cellulose) were very low, showing a minor influence of primary biological aerosol particles during the North European winter. The fraction of modern carbon generally varied from 0.57 (Melpitz) to 0.91 (Birkenes), showing an opposite trend compared to the molecular tracers and TC. Total concentrations of 10 biogenic and anthropogenic carboxylic acids, mainly of secondary origin, were 4–53 ng m−3, with the lowest concentrations observed at Birkenes and the highest at Melpitz. However, the highest relative concentrations of carboxylic acids (normalized to TC) were observed at the most northern sites. Levels of organosulphates and nitrooxy organosulphates varied more than two orders of magnitude, from 2 to 414 ng m−3, between individual sites and samples. The three sites Melpitz, Rotterdam and Cabauw, located closest to source regions in continental Europe, showed very high levels of organosulphates and nitrooxy organosulphates (up to 414 ng m−3) during the first two weeks of the study, while low levels (<7 ng m−3) were found at all sites except Melpitz during the last week. The large variation in organosulphate levels probably reflects differences in the presence of acidic sulphate aerosols, known from laboratory studies to accelerate the formation of these compounds. On average, the ratio of organic sulphate to inorganic sulphate was 1.5 ± 1.0% (range 0.1–3.4%). Latin-hypercube source apportionment techniques identified biomass burning as the major source of OC for all samples at all sites (typically >40% of TC), while use and combustion of fossil fuels was the second most important source. Furthermore, EC from biomass burning accounted for 7–16% of TC, whereas EC from fossil sources contributed to <2–23% of TC, of which the highest percentages were observed for low-concentration aerosol samples. Unresolved non-fossil sources (such as cooking and biogenic secondary organic aerosols) did not account for more than 5–12% of TC. The results confirm that wood combustion is a major source to OC and EC in Northern Europe during winter. © 2017 Elsevier Ltd Chemicals/CAS: arabinitol, 2152-56-9; carbon, 7440-44-0; carbon 14, 14762-75-5; cellulose, 61991-22-8, 68073-05-2, 9004-34-6; levoglucosan, 498-07-7; mannitol, 69-65-8, 87-78-5; sulfate, 14808-79-8

In the current study, a new method is introduced with which the rate-limiting factor of biodegradation processes of hydrophobic chemicals in organic and aqueous systems can be determined. The novelty of this approach lies in the combination of a free concentration-based kinetic model with measurements of both free and total concentrations in time. This model includes microbial biodegradation activity of the chemical in the aqueous phase and chemical sorption kinetics with respectto organic carbon and aqueous phases. The time dependency of free and total concentrations of 7-acetyl-1,1,3,4,4,6-hexamethyltetrahydronaphthalene and 7-acetyl-1,1,3,4,4,6-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta(g) -2-benzopyrane in activated sludge was experimentally determined in vitro. Evaporation losses from the test system were also determined. Least-squares regression to optimize the model parameters resulted in a model that is in accordance with the experimental data. Additionally, the model shows that a comparison between the decrease of free and total chemical concentrations in time, in combination with an independent measurement of the organic carbon/water partition coefficient provides information about the rate-limiting step of the degradation process. This information can be used by sewage treatment plant managers to decide whether the microbial biodegradation activity itself or the desorption from organic carbon to the aqueous phase should be improved.

Aluminium has received great attention in the second half of the 20th century, mainly in the context of the acid rain problem mostly in forest soils. In this research the effect of land use and depth of the groundwater on Al, pH and DOC concentration in groundwater under Dutch sandy soils has been studied. Both pH and DOC concentration play a major role in the speciation of Al in solution. Furthermore, the equilibrium with mineral phases like gibbsite, amorphous Al(OH)3 and imogolite, has been considered. Agricultural and natural land use were expected to have different effects on the pH and DOC concentration, which in turn could influence the total Al concentration and the speciation of Al in groundwater at different depths (phreatic, shallow and deep). An extensive dataset (n = 2181) from the national and some provincial monitoring networks on soil and groundwater quality was used. Land use type and groundwater depth did influence the pH, and Al and DOC concentrations in groundwater samples. The Al concentration ranged from <0.4 μmol L-1 at pH > 7 to 1941 μmol L-1 at pH < 4; highest Al concentrations were found for natural-phreatic groundwater. The DOC concentration decreased and the median pH increased with depth of the groundwater. Natural-phreatic groundwater showed lower pH than the agricultural-phreatic groundwater. Highest DOC concentrations were found for the agricultural-phreatic groundwater, induced by the application of organic fertilizers. Besides inorganic complexation, the NICA-Donnan model was used to calculate Al3+ concentrations for complexation with DOC. Below pH 4.5 groundwater samples were mainly in disequilibrium with a mineral phase. This disequilibrium is considered to be the result of kinetic constraints or equilibrium with organic matter. Log K values were derived by linear regression and were close to theoretical values for Al(OH)3 minerals (e.g. gibbsite or amorphous Al(OH)3), except for natural-phreatic groundwater for which lower log K values were found. Complexation of Al with DOC is shown to be an important factor for the Al concentrations, especially at high DOC concentrations as was found for agricultural-phreatic groundwater. © 2007 Elsevier Ltd. All rights reserved.

The success of shale gas exploration and production in the United States has triggered other countries around the world to look into possibilities of producing gas from different shales. As it turns out, one of the main difficulties when looking for shale gas is obtaining an in depth understanding of the shale formations and interpret where the sweet spots for gas production will be. This is mainly caused by the large differences in properties of shale formations. To improve our understanding of the vertical and lateral property changes that determine high and low productivity zones in shales, TNO has proposed a workflow including well log interpretation, mud log interpretation, depth modeling, organic geochemistry, basin modeling, palynology, electron microscope analyses, mineral typing and porosity identification and characterization. This method serves as a solid basis for sweet spot determination and proper resource estimates. The proposed method has been applied to the two main possible shale gas reservoirs in the Netherlands; the Lower Jurassic Posidonia Shale Formation (PSF) and the Carboniferous (Namurian) Epen Formation. The latter is of particular interest as it contains the highly organic basal Geverik Member (GM). For the two formations detailed and accurate depth maps have been produced. Research on the PSF shows that a number of areas are expected to have reached gas maturity, together around a fifth of the total area of the formation. Besides shale gas there appears to be potential for shale oil. High productivity zones within these shales are expected in the deepest part of formation and orientated along the distribution axis within the West Netherlands Basin. In the multidisciplinary workflow a 3D faciesmodel of the formation is created using palynology and organofacies to detect prospective layers within the formation. This faciesmodel is then used in combination with log-interpretaion, seismic interpretation and sedimentological interpretation to detect most prospective zones and areas. FIB-SEM microscopy shows that coccoliths present in the formation can have large favourable effects on the porosity and permeability providing for a micropermeability pathway for oil and gas when interconnected. When the proposed workflow is applied to the Geverik Member, a correlation between silica content and Total Organic Carbon (TOC) is found, i.e. log-derived TOC is in general close to 10% when the dominant mineral type is silica. Geomechanical analysis of rock properties shows that the lower zone of the Geverik Member is the favourable layer to target, i.e. the layer is dominantly build up of quartz and silica suggesting preferential conditions for hydraulic stimulation.

Trace and major elements concentrations in PM10 and PM2.5 were measured at 20 sites spread in the Barcelona metropolitan area (1 rural background, 6 urban background, 13 road traffic sites) and at 1 reference site. Three 2-week samples per site and size fraction were collected during 2009 using low volume samplers, adding a total of 120 samples. Collected samples were analysed for elemental composition using Energy Dispersive X-ray fluorescence (XRF). EC, OC, and hopanes and steranes concentrations in PM2.5 were determined. Positive Matrix Factorisation (PMF) model was used for a source apportionment analysis. The work was performed as part of the ESCAPE project.Elements were found in concentrations within the usual range in Spanish urban areas. Mineral elements were measured in higher concentrations during the warm season, due to enhanced resuspension; concentrations of fueloil combustion elements were also higher in summer. Elements in higher concentration at the traffic sites were: Ba, Cr, Cu, Fe, Mn, Mo, Pb, Sn, Zn and Zr. Spatial variations related to non-traffic sources were observed for concentrations of Br, Cl, K, and Na (sea salt origin) and Ni, V and S (shipping emissions), which were higher at the coastal sites, as well as for Zn and Pb, higher at sites closer to industrial facilities.Five common sources for PM10 and PM2.5 were identified by PMF: road traffic (with tracers Ba, Cr, Cu, Fe, Mo and Zn); fueloil combustion (Ni and V); secondary sulphate; industry (Pb and Zn); and mineral source (Al, Ca, Mg, Si, Sr and Ti). A marine aerosol source, a mixture of sea salt with aged anthropogenic aerosols, was found only in PM10. EC, hopanes and steranes concentrations correlate strongly with the PM10 road traffic source contributions, being hence all attributed to the same source. OC may arise from other sources in addition to road traffic and have a high contribution of secondary OC.Significant spatial and temporal variation in the PM2.5 and PM10 elemental composition was found. Spatial patterns differed per element, related to the main source. The identified source contributions can be used in health studies of source-specific particles. © 2014 Elsevier Ltd. Chemicals/CAS: barium ion, 22541-12-4; bromine, 7726-95-6; chlorine, 13981-72-1, 7782-50-5; chromium, 14092-98-9, 16065-83-1, 7440-47-3; hydrochloric acid, 7647-01-0; iron, 14093-02-8, 53858-86-9, 7439-89-6; lead, 13966-28-4, 7439-92-1; manganese, 16397-91-4, 7439-96-5; molybdenum, 7439-98-7; nickel, 7440-02-0; potassium, 7440-09-7; prednisolone, 50-24-8; sodium, 7440-23-5; sodium nitrate, 7631-99-4; sulfate, 14808-79-8; sulfur, 13981-57-2, 7704-34-9; tin, 14314-35-3, 7440-31-5; vanadium, 7440-62-2; zinc, 14378-32-6, 7440-66-6; zirconium, 14940-68-2, 7440-67-7