Bad reporting or bad science? Systematic data evaluation as a means to improve the use of peer-reviewed studies in risk assessments of chemicals

2014 | Hum. Ecol. Risk Assess. | 20 (6) (1427-1445)

In this study we assess the applicability of a set of reliability criteria proposed by Ågerstrand et al. This was done by evaluating the reliability of 12 non-standard peer-reviewed ecotoxicity and toxicity studies for Bisphenol A. There was an overall agreement between the evaluator and the authors of the papers regarding the result of the evaluations. This suggests that the criteria offer enough guidance to be a useful and consistent evaluation tool. It provides a transparent and structured approach, and ensures that a minimum and similar set of criteria is used. The evaluation of the peer-reviewed ecotoxicity and toxicity studies concludes that important information is sometimes missing, and therefore the studies do not always meet common regulatory requirements regarding reporting. Whether this is due to insufficient reporting or due to poorly performed studies is not known. To improve the reporting, and thereby promote reliability and reproducibility, researchers, reviewers, and editors are recommended to use the suggested criteria as a guideline. In conclusion, in order to improve the reliability of peer-reviewed studies, and to increase their use in regulatory risk assessments of chemicals, the dialog between regulators, researchers, and editors regarding how to evaluate and report studies needs to be strengthened.

CO2-induced terrestrial climate feedback mechanism: From carbon sink to aerosol source and back

Kulmala, M.; Nieminen, T.; Nikandrova, A.; Lehtipalo, K.; Manninen, H.E.; Kajos, M.A.; Kolari, P.; Lauri, A.; Petäjä, T.; Krejci, R.; Hansson, H.-C.; Swietlicki, E.; Lindroth, A.; Christensen, T.R.; Arneth, A.; Hari, P.; Bäck, J.; Vesala, T.; Kerminen V.-M.
2014 | Boreal Environ. Res. | 19 (122-131)

Feedbacks mechanisms are essential components of our climate system, as they either increase or decrease changes in climate-related quantities in the presence of external forcings. In this work, we provide the first quantitative estimate regarding the terrestrial climate feedback loop connecting the increasing atmospheric carbon dioxide concentration, changes in gross primary production (GPP) associated with the carbon uptake, organic aerosol formation in the atmosphere, and transfer of both diffuse and global radiation. Our approach was to combine process-level understanding with comprehensive, long-term field measurement data set collected from a boreal forest site in southern Finland. Our best estimate of the gain in GPP resulting from the feedback is 1.3 (range 1.02-1.5), which is larger than the gains of the few atmospheric chemistry-climate feedbacks estimated using large-scale models. Our analysis demonstrates the power of using comprehensive field measurements in investigating the complicated couplings between the biosphere and atmosphere on one hand, and the need for complementary approaches relying on the combination of field data, satellite observations model simulations on the other hand.

Class separation of lipids and polycyclic aromatic hydrocarbons in normal phase High Performance Liquid Chromatography – A prospect for analysis of aromatics in edible vegetable oils and biodiesel exhaust particulates

Olsson, P; Sadiktsis, I.; Holmbäck, J.; Westerholm, R.
2014 | J. Chromatogr. A | 1360 (39-46)

The retention characteristics of the major lipid components in biodiesels and edible oils as well as representative polycyclic aromatic compounds (PAHs) have been investigated on five different normal phase HPLC stationary phases, in order to optimize class separation for an automatized online HPLC cleanup of PAHs prior GC-MS analysis. By stepwise comparison of different hexane/MTBE compositions as mobile phases on cyano-, phenyl-, pentabromobenzyl-, nitrophenyl- and amino- modified silica columns, the capacity and selectivity factors for each analyte and column could be calculated. It was concluded that the most suitable column for backflush isolation of PAHs in biodiesel and edible oil matrices was the pentabromobenzyl-modified silica (PBB). A previously described online HPLC-GC-MS system using the PBB column was then evaluated by qualitative and quantitative analysis of a biodiesel exhaust particulate extract and a vegetable oil reference material. The GC-MS full scan analysis of the biodiesel particulate extract showed that the lipids had been removed from the sample and a fraction containing PAHs and oxygenated derivatives thereof had been isolated. Quantified mass fractions of PAHs of the reference material BCR-458 agreed well for most of the certified PAH mass fractions in the spiked coconut oil reference material.

On the potential vegetation feedbacks that enhance phosphorus availability – insights from a process-based model linking geological and ecological timescales

C. Buendía; S. Arens; T. Hickler; S. I. Higgins; P. Porada; A. Kleidon;
2014 | Biogeosciences | 11 (13) (3661-3683)

Comparing land use regression and dispersion modelling to assess residential exposure to ambient air pollution for epidemiological studies.

de Hoogh, K.; Korek, M.; Vienneau, D.; Keuken, M.; Kukkonen, J.; Nieuwenhuijsen, M. J.; Badaloni, C.; Beelen, R.; Bolignano, A.; Cesaroni, G.; Pradas, M.C.; Cyrys, J.; Douros, J.; Eeftens, M.; Forastiere, F.; Forsberg, B.; Fuks, K.; Gehringk, U.; Gryparis, A.; Gulliver, J.; Hansell, A. L.; Hoffmann, B.; Johansson, C.; Jonkers, S.; Kangas, L.; Katsouyanni, K.; Künzli, N.; Lanki, T.; Memmesheimer, M.; Moussiopoulos, N.; Modig, L.; Pershagen, G.; Probst-Hensch, N.; Schindler, C.; Schikowski, T.; Sugiri D.; Teixidó, O.; Tsai, M.-Y.; Yli-Tuomi, T.; Brunekreef, B.; Hoekk, G.; Bellander, T.
2014 | Environ Int | 73 (382-392)

Background: Land-use regression (LUR) and dispersion models (DM) are commonly used for estimating individual air pollution exposure in population studies. Few comparisons have however been made of the performance of these methods.
Objectives: Within the European Study of Cohorts for Air Pollution Effects (ESCAPE) we explored the differences between LUR and DM estimates for NO2, PM10 and PM2.5.
Methods: The ESCAPE study developed LUR models for outdoor air pollution levels based on a harmonised monitoring campaign. In thirteen ESCAPE study areas we further applied dispersion models. We compared LUR and DM estimates at the residential addresses of participants in 13 cohorts for NO2; 7 for PM10 and 4 for
PM2.5. Additionally, we compared the DM estimates with measured concentrations at the 20–40 ESCAPE monitoring sites in each area.
Results: The median Pearson R (range) correlation coefficients between LUR and DM estimates for the annual average concentrations of NO2, PM10 and PM2.5 were 0.75 (0.19–0.89), 0.39 (0.23–0.66) and 0.29 (0.22–0.81) for 112,971 (13 study areas), 69,591 (7) and 28,519 (4) addresses respectively. The median Pearson R correlation
coefficients (range) between DM estimates and ESCAPE measurements were of 0.74 (0.09–0.86) for NO2; 0.58 (0.36–0.88) for PM10 and 0.58 (0.39–0.66) for PM2.5.
Conclusions: LUR and dispersion model estimates correlated on average well for NO2 but only moderately for PM10 and PM2.5,with large variability across areas.DMpredicted a moderate to large proportion of the measured variation for NO2 but less for PM10 and PM2.5.

Organosulfates and organic acids in Arctic aerosols: Speciation, annual variation and concentration levels

Hansen, A.M.K.; Kristensen, K.; Nguyen, Q.T.; Zare, A.; Cozzi, F.; Nojgaard, J.K.; Skov, H.; Brandt, J.; Christensen, J.H.; Ström, J.; Tunved, P.; Krejci, R.; Glasius M.
2014 | Atmos. Chem. Phys. | 14 (15) (7807-7823)

Sources, composition and occurrence of secondary organic aerosols in the Arctic were investigated at Zeppelin Mountain, Svalbard, and Station Nord, northeastern Greenland, during the full annual cycle of 2008 and 2010, respectively. Speciation of organic acids, organosulfates and nitrooxy organosulfates - from both anthropogenic and biogenic precursors were in focus. A total of 11 organic acids (terpenylic acid, benzoic acid, phthalic acid, pinic acid, suberic acid, azelaic acid, adipic acid, pimelic acid, pinonic acid, diaterpenylic acid acetate and 3-methyl-1,2,3-butanetricarboxylic acid), 12 organosulfates and 1 nitrooxy organosulfate were identified in aerosol samples from the two sites using a high-performance liquid chromatograph (HPLC) coupled to a quadrupole Time-of-Flight mass spectrometer. At Station Nord, compound concentrations followed a distinct annual pattern, where high mean concentrations of organosulfates (47 +/- 14 ng m(-3)) and organic acids (11.5 +/- 4 ng m(-3)) were observed in January, February and March, contrary to considerably lower mean concentrations of organosulfates (2 +/- 3 ng m(3-)) and organic acids (2.2 +/- 1 ng m(-3)) observed during the rest of the year. At Zeppelin Mountain, organosulfate and organic acid concentrations remained relatively constant during most of the year at a mean concentration of 15 +/- 4 ng m(-3) and 3.9 +/- 1 ng m(-3), respectively. However during four weeks of spring, remarkably higher concentrations of total organosulfates (23-36 ng m(-3)) and total organic acids (7-10 ngm(-3)) were observed. Elevated organosulfate and organic acid concentrations coincided with the Arctic haze period at both stations, where northern Eurasia was identified as the main source region. Air mass transport from northern Eurasia to Zeppelin Mountain was associated with a 100% increase in the number of detected organosulfate species compared with periods of air mass transport from the Arctic Ocean, Scandinavia and Greenland. The results from this study suggested that the presence of organic acids and organosulfates at Station Nord was mainly due to long-range transport, whereas indications of local sources were found for some compounds at Zeppelin Mountain. Furthermore, organosulfates contributed significantly to organic matter throughout the year at Zeppelin Mountain (annual mean of 13 +/- 8 %) and during Arctic haze at Station Nord (7 +/- 2 %), suggesting organosulfates to be important compounds in Arctic aerosols.

Laboratory intercomparison of marine particulate digestions including Piranha: a novel chemical method for dissolution of polyethersulfone filters

D. C. Ohnemus; M. E. Auro; R. M. Sherrell; M. Lagerström; P. L. Morton; B. S. Twining; Sara Rauschenberg; P. J. Lam
2014 | Limnol. Oceanogr. Meth.

Desorption kinetics of sulfonamide and trimethoprim antibiotics in soils assessed with diffusive gradients in thin-films

Chang-Er Chen, Kevin C Jones, Guang-Guo Ying, Hao Zhang
2014 | Environ. Sci. Technol. | 48 (10) (5530-5536)

A feasibility study of mapping light-absorbing carbon using a taxi fleet as a mobile platform.

Krecl, P.; Johansson, C.; Ström, J.; Lövenheim, B.; Gallet, J.
2014 | TELLUS B | 66

Carbon-containing particles are associated with adverse health effects, and their light-absorbing fractions were recently estimated to be the second largest contributor to global warming after carbon dioxide. Knowledge on the spatiotemporal variability of light-absorbing carbon (LAC) particles in urban areas is relevant for air quality management and to better diagnose the population exposure to these particles. This work reports on the first mobile LAC mass concentrations (MLAC) measured on-board four taxis in the Stockholm metropolitan area in November 2011. On average, concentrations were higher and more variable during daytime (median of 1.9 µg m−3 and median absolute deviation of 2.3 µg m−3). Night-time (21:00–05:00) measurements were very similar for all road types and also compared to levels monitored at an urban background fixed site (median of 0.9 µg m−3). We observed a large intra-urban variability in concentrations, with maxima levels inside road tunnels (median and 95th percentile of 7.5 and 40.1 µg m−3, respectively). Highways presented the second ranked concentrations (median and 95th percentile of 3.2 and 9.7 µg m−3, respectively) associated with highest vehicle speed (median of 65 km h−1), traffic rates (median of 62 000 vehicles day−1 and 1500 vehicles h−1) and diesel vehicles share (7–10%) when compared to main roads, canyon streets, and local roads. Multiple regression modelling identified hourly traffic rate and MLAC concentration measured at an urban background site as the best predictors of on-road concentrations, but explained only 25% of the observed variability. This feasibility study proved to be a time- and cost-effective approach to map out ambient MLAC concentrations in Stockholm and more research is required to represent the distribution in other periods of the year. Simultaneous monitoring of other pollutants, closely correlated to MLAC levels in traffic-polluted environments, and including video recording of road and traffic changes would be an asset.

Primary and secondary organics in the tropical Amazonian rainforest aerosols: Chiral analysis of 2-methyltetraols

Gonzales N.J.D.; Borg-Karlsson, A.-K.; Artaxo, P.; Guenther, A.; Krejci, R.; Noziere, B.; Noone K.J.
2014 | Environ. Sci.: Processes Impacts | 16 (6) (1413-1421)

This work presents the application of a new method to facilitate the distinction between biologically produced (primary) and atmospherically produced (secondary) organic compounds in ambient aerosols based on their chirality. The compounds chosen for this analysis were the stereomers of 2-methyltetraols, (2R, 3S)- and (2S, 3R)-methylerythritol, (L- and D-form, respectively), and (2S, 3S)- and (2R, 3R)-methylthreitol (L- and D-form), shown previously to display some enantiomeric excesses in atmospheric aerosols, thus to have at least a partial biological origin. In this work PM10 aerosol fractions were collected in a remote tropical rainforest environment near Manaus, Brazil, between June 2008 and June 2009 and analysed. Both 2-methylerythritol and 2-methylthreitol displayed a net excess of one enantiomer (either the L- or the D-form) in 60 to 72% of these samples. These net enantiomeric excesses corresponded to compounds entirely biological but accounted for only about 5% of the total 2-methyltetrol mass in all the samples. Further analysis showed that, in addition, a large mass of the racemic fractions (equal mixtures of D- and L-forms) was also biological. Estimating the contribution of secondary reactions from the isomeric ratios measured in the samples (=ratios 2-methylthreitol over 2-methylerythritol), the mass fraction of secondary methyltetrols in these samples was estimated to a maximum of 31% and their primary fraction to a minimum of 69%. Such large primary fractions could have been expected in PM10 aerosols, largely influenced by biological emissions, and would now need to be investigated in finer aerosols. This work demonstrates the effectiveness of chiral and isomeric analyses as the first direct tool to assess the primary and secondary fractions of organic aerosols.

A review of sea-spray aerosol source functions using a large global set of sea salt aerosol concentration measurements

Grythe, H.; Ström, J.; Krejci, R.; Quinn, P.; Stohl A.
2014 | Atmos. Chem. Phys. | 14 (3) (1277-1297)

Sea-spray aerosols (SSA) are an important part of the climate system because of their effects on the global radiative budget - both directly as scatterers and absorbers of solar and terrestrial radiation, and indirectly as cloud condensation nuclei (CCN) influencing cloud formation, lifetime, and precipitation. In terms of their global mass, SSA have the largest uncertainty of all aerosols. In this study we review 21 SSA source functions from the literature, several of which are used in current climate models. In addition, we propose a new function. Even excluding outliers, the global annual SSA mass produced spans roughly 3-70 Pg yr(-1) for the different source functions, for particles with dry diameter D-p < 10 mu m, with relatively little interannual variability for a given function. The FLEXPART Lagrangian particle dispersion model was run in backward mode for a large global set of observed SSA concentrations, comprised of several station networks and ship cruise measurement campaigns. FLEXPART backward calculations produce gridded emission sensitivity fields, which can subsequently be multiplied with gridded SSA production fluxes in order to obtain modeled SSA concentrations. This allowed us to efficiently and simultaneously evaluate all 21 source functions against the measurements. Another advantage of this method is that source-region information on wind speed and sea surface temperatures (SSTs) could be stored and used for improving the SSA source function parameterizations. The best source functions reproduced as much as 70% of the observed SSA concentration variability at several stations, which is comparable with "state of the art" aerosol models. The main driver of SSA production is wind, and we found that the best fit to the observation data could be obtained when the SSA production is proportional to U-10(3.5), where U-10 is the source region averaged 10m wind speed. A strong influence of SST on SSA production, with higher temperatures leading to higher production, could be detected as well, although the underlying physical mechanisms of the SST influence remains unclear. Our new source function with wind speed and temperature dependence gives a global SSA production for particles smaller than D-p < 10 mu m of 9 Pg yr(-1), and is the best fit to the observed concentrations.

Hygroscopicity, CCN and volatility properties of submicron atmospheric aerosol in a boreal forest environment during the summer of 2010

Hong, J; Hakkinen, SAK; Paramonov, M; Aijala, M; Hakala, J; Nieminen, T; Mikkila, J; Prisle, NL; Kulmala, M; Riipinen, I; Bilde, M; Kerminen, VM; Petaja, T
2014 | Atmos. Chem. Phys. | 14 (9) (4733-4748)

A Volatility-Hygroscopicity Tandem Differential Mobility Analyzer (VH-TDMA) was applied to study the hygroscopicity and volatility properties of submicron atmospheric aerosol particles in a boreal forest environment in Hyytiala, Finland during the summer of 2010. Aitken and accumulation mode internally mixed particles (50 nm, 75 nm and 110 nm in diameter) were investigated. Hygroscopicity was found to increase with particle size. The relative mass fraction of organics and SO42- is probably the major contributor to the fluctuation of the hygroscopicity for all particle sizes. The Cloud Condensation Nuclei Counter (CCNC)-derived hygroscopicity parameter kappa was observed to be slightly higher than kappa calculated from VH-TDMA data under sub-saturated conditions, potential reasons for this behavior are discussed shortly. Also, the size-resolved volatility properties of particles were investigated. Upon heating, more small particles evaporated compared to large particles. There was a significant amount of aerosol volume (non-volatile material) left, even at heating temperatures of 280 degrees C. Using size resolved volatility-hygroscopicity analysis, we concluded that there was always hygroscopic material remaining in the particles at different heating temperatures, even at 280 degrees C. This indicates that the observed non-volatile aerosol material did not consist solely of black carbon.

Contact information

Visiting addresses:

Geovetenskapens Hus,
Svante Arrhenius väg 8, Stockholm

Arrheniuslaboratoriet, Svante Arrhenius väg 16, Stockholm (Unit for Analytical and Toxicological Chemistry)

Mailing address:
Department of Environmental Science and Analytical Chemistry (ACES)
Stockholm University
106 91 Stockholm

Press enquiries should be directed to:

Stella Papadopoulou
Science Communicator
Phone +46 (0)8 674 7212
Mobile +46 (0)70 1808234
stella.papadopoulou@aces.su.se