Accelerated delivery of polychlorinated biphenyls (PCBs) in recent sediments near a large seabird colony in Arctic Canada

Polychlorinated biphenyls (PCBs) were measured in sediment cores from ponds located near a large seabird colony at Cape Vera, Devon Island, Arctic Canada. Surface sediment PCB concentrations were ∼5× greater in seabird-affected sites relative to a nearby control pond and were correlated with independent indicators of seabird activity including, sedimentary δ¹⁵N and lakewater chlorophyll a and cadmium concentrations. PCB fluxes were amongst the highest recorded from the High Arctic, ranging from 290 to 2400 ng m⁻² yr⁻¹. Despite a widespread ban of PCBs in the mid-1970s, PCB accumulation rates in our cores increased, with the highest values recorded in the most recent sediments. Possible mechanisms for the recent PCB increases include a vertical flux step driven by seabird-delivered nutrients and/or delayed loading of PCBs from the catchment into the ponds. The high PCB levels recorded in the seabird-affected sites suggest that seabird colonies are exposing coastal ecosystems to elevated levels of contaminants.     

Global temperature change from the transport sectors: Historical development and future scenarios

Transport affects climate directly and indirectly through mechanisms that operate on very different timescales and cause both warming and cooling. We calculate contributions to the historical development in global mean temperature for the main transport sectors (road transport, aviation, shipping and rail) based on estimates of historical emissions and by applying knowledge about the various forcing mechanisms from detailed studies. We also calculate the development in future global mean temperature for four transport scenarios consistent with the IPCC SRES scenarios, one mitigation scenario and one sensitivity test scenario. There are large differences between the transport sectors in terms of sign and magnitude of temperature effects and with respect to the contributions from the long- and short-lived components. Since pre-industrial times, we calculate that transport in total has contributed 9% of total net man-made warming in the year 2000. The dominating contributor to warming is CO₂, followed by tropospheric O₃. By sector, road transport is the largest contributor; 11% of the warming in 2000 is due to this sector. Likewise, aviation has contributed 4% and rail ～1%. Shipping, on the other hand, has caused a net cooling up to year 2000, with a contribution of ?7%, due to the effects of SO₂ and NOx emissions. The total net contribution from the transport sectors to total man-made warming is ～15% in 2050, and reaches 20% in 2100 in the A1 and B1 scenarios. For all scenarios and throughout the century, road transport is the dominating contributor to warming. Due to the anticipated reduction in sulphur content of fuels, the net effect of shipping changes from cooling to warming by the end of the century. Significant uncertainties are related to the estimates of historical and future net warming mainly due to cirrus, contrails and aerosol effects, as well as uncertainty in climate sensitivity.     

Sorption and desorption of imidazolium based ionic liquids in different soil types

This study investigates the influence of the two different clay minerals kaolinite and smectite as well as of organic matter on the cation sorption and desorption behaviour of three imidazolium based ionic liquids -1-butyl-3-methyl-imidazolium tetrafluoroborate (IM14 BF(4)), 1-methyl-3-octyl-imidazolium tetrafluoroborate (IM18 BF(4)) and 1-butyl-3-methyl-imidazolium bis[(trifluoromethyl)sulfonyl]imide (IM14 (CF(3)SO(2))(2)N) - in soil. The German standard soil Lufa 2.2 - a natural soil classified as a loamy sand - was the basis substrate for the different soil compositions and also served as a reference soil. The addition of organic matter and clays increases the sorption of the substances and in particular smectite had striking effects on the sorption capacity for all three ionic liquids indicating that ionic interactions play an important role for sorption and desorption processes of ionic liquids in soil. One exception was for kaolinite-containing soils and the IM14 cation: with (CF(3)SO(2))(2)N(-) as an anion the sorption was identical at either 10 wt% or 15 wt% clay content, and with BF(4)(-) sorption was even lower at 15 wt% kaolinite than at 10 wt%. Desorption was weak for IM18 BF(4), presumably owing to the longer alkyl side chain. With regard to the influence of kaolinite on desorption, the same pattern was observed as it was found for the sorption of IM14 BF(4) and IM14 (CF(3)SO(2))(2)N.     

Windsor, Ontario exposure assessment study: design and methods validation of personal, indoor, and outdoor air pollution monitoring

The Windsor, Ontario Exposure Assessment Study evaluated the contribution of ambient air pollutants to personal and indoor exposures of adults and asthmatic children living in Windsor, Ontario, Canada. In addition, the role of personal, indoor, and outdoor air pollution exposures upon asthmatic children's respiratory health was assessed. Several active and passive sampling methods were applied, or adapted, for personal, indoor, and outdoor residential monitoring of nitrogen dioxide, volatile organic compounds, particulate matter (PM; PM-2.5 pm [PM2.5] and < or =10 microm [PM10] in aerodynamic diameter), elemental carbon, ultrafine particles, ozone, air exchange rates, allergens in settled dust, and particulate-associated metals. Participants completed five consecutive days of monitoring during the winter and summer of 2005 and 2006. During 2006, in addition to undertaking the air pollution measurements, asthmatic children completed respiratory health measurements (including peak flow meter tests and exhaled breath condensate) and tracked respiratory symptoms in a diary. Extensive quality assurance and quality control steps were implemented, including the collocation of instruments at the National Air Pollution Surveillance site operated by Environment Canada and at the Michigan Department of Environmental Quality site in Allen Park, Detroit, MI. During field sampling, duplicate and blank samples were also completed and these data are reported. In total, 50 adults and 51 asthmatic children were recruited to participate, resulting in 922 participant days of data. When comparing the methods used in the study with standard reference methods, field blanks were low and bias was acceptable, with most methods being within 20% of reference methods. Duplicates were typically within less than 10% of each other, indicating that study results can be used with confidence. This paper covers study design, recruitment, methodology, time activity diary, surveys, and quality assurance and control results for the different methods used.     

Wastewater reuse in Mediterranean semi-arid areas: The impact of discharges of tertiary treated sewage on the load of polar micro pollutants in the Llobregat river (NE Spain)

The presence of sewage-borne micro contaminants in environmental waters is directly related to the discharge of treated effluents from wastewater treatment plants (WWTP) and the flow rate of the receiving river waters. Mediterranean rivers, in particular, are characterized by important fluctuations in the flow rates and heavy pollution pressures resulting from extensive urban, industrial and agricultural activities. This translates into contamination levels in these rivers often higher than those in other larger European basins. The present work provides an overview of the occurrence of five groups of organic contaminants (131 compounds) namely pharmaceuticals, illicit drugs, polar pesticides, estrogens, alkylphenols and related ethoxylates in WWTP tertiary treatment effluents. Data gathered during a period of water reuse carried out in the lower stretch of the Llobregat river (NE Spain), in the surroundings of the town of Barcelona as a consequence of the severe drought that took place along the years 2007-2008 are presented as illustrative example. In general, measured concentrations of the target compounds were in the low to mid ng L⁻¹ range. The total concentration of each compound class downstream to the discharge point was similar or slightly higher than that found upstream. Regarding the loads calculated for each compound, the relative contribution from the river upstream and the tertiary effluent were highly compound depending with no apparent trend. However, estimation of the overall bulk loads for each compound class determined in the Llobregat river showed the following rank order: pharmaceuticals > alkylphenols > pesticides > illicit drugs ? estrogens.     

Echoes from the Past: A Healthy Baltic Sea Requires More Effort

Integrated sediment multiproxy studies and modeling were used to reconstruct past changes in the Baltic Sea ecosystem. Results of natural changes over the past 6000 years in the Baltic Sea ecosystem suggest that forecasted climate warming might enhance environmental problems of the Baltic Sea. Integrated modeling and sediment proxy studies reveal increased sea surface temperatures and expanded seafloor anoxia (in deep basins) during earlier natural warm climate phases, such as the Medieval Climate Anomaly. Under future IPCC scenarios of global warming, there is likely no improvement of bottom water conditions in the Baltic Sea. Thus, the measures already designed to produce a healthier Baltic Sea are insufficient in the long term. The interactions between climate change and anthropogenic impacts on the Baltic Sea should be considered in management, implementation of policy strategies in the Baltic Sea environmental issues, and adaptation to future climate change.     

The Significance of the North Water Polynya to Arctic Top Predators

The North Water polynya (~76°N to 79°N and 70°W to 80°W) is known to be an important habitat for several species of marine mammals and sea birds. For millennia, it has provided the basis for subsistence hunting and human presence in the northernmost part of Baffin Bay. The abundance of air-breathing top predators also represents a potential source of nutrient cycling that maintains primary production. In this study, aerial surveys conducted in 2009 and 2010 were used for the first time to map the distribution and estimate the abundance of top predators during spring in the North Water. Belugas (Delphinapterus leucas) were not detected north of 77°20′N but were found along the coast of West Greenland and offshore in the middle of the North Water with an abundance estimated at 2245 (95 % CI 1811–2783). Narwhals (Monodon monoceros) were widely distributed on the eastern side of the North Water with an estimate of abundance of 7726 (3761–15 870). Walruses (Odobenus rosmarus) were found across the North Water over both shallow and deep (>500 m) water with an estimated abundance of 1499 (1077–2087). Bearded (Erignathus barbatus) and ringed seals (Phoca hispida) used the large floes of ice in the southeastern part of the North Water for hauling out. Most polar bears (Ursus maritimus) were detected in the southern part of the polynya. The abundances of bearded and ringed seals were 6016 (3322–10 893) and 9529 (5460–16 632), respectively, and that of polar bears was 60 (12–292). Three sea bird species were distributed along the Greenland coast (eiders, Somateria spp.), in leads and cracks close to the Greenland coast (little auks, Alle alle) or widely in open water (thick-billed guillemots, Uria lomvia).     

Sample damage during X-ray fluorescence analysis--case study on ammonium salts in atmospheric aerosols

Atmospheric aerosols can consist of, amongst others, compounds like NH(4)NO(3) or (NH(4))(2)SO(4). Such components can suffer radiation damage and/or evaporate during EDXRF measurements, providing errors on successively applied analysis. The aim of this work is to investigate the influence of measurements using conventional EDXRF on the volatile compounds and to compare it with the influence of polarized beam EDXRF using secondary targets (and hence indirect irradiation). The effect of different parameters (acquisition time, accelerating voltage, current and medium) on the concentration loss was studied. The measurements performed in vacuum during a long period lead to the highest losses of volatile compounds. The influence of direct irradiation was proved to be larger than the indirect variant.