Combining web‐based tools for transparent evaluation of data for risk assessment: developmental effects of bisphenol A on the mammary gland as a case study

Linda Molander; Annika Hanberg; Christina Rudén; Marlene Ågerstrand; Anna Beronius
2016 | J Appl Toxicol

Different tools have been developed that facilitate systematic and transparent evaluation and handling of toxicity data in the risk assessment process. The present paper sets out to explore the combined use of two web-based tools for study evaluation and identification of reliable data relevant to health risk assessment. For this purpose, a case study was performed using in vivo toxicity studies investigating low-dose effects of bisphenol A on mammary gland development. The reliability of the mammary gland studies was evaluated using the Science in Risk Assessment and Policy (SciRAP) criteria for toxicity studies. The Health Assessment Workspace Collaborative (HAWC) was used for characterizing and visualizing the mammary gland data in terms of type of effects investigated and reported, and the distribution of these effects within the dose interval. It was then investigated whether there was any relationship between study reliability and the type of effects reported and/or their distribution in the dose interval. The combination of the SciRAP and HAWC tools allowed for transparent evaluation and visualization of the studies investigating developmental effects of BPA on the mammary gland. The use of these tools showed that there were no apparent differences in the type of effects and their distribution in the dose interval between the five studies assessed as most reliable and the whole data set. Combining the SciRAP and HAWC tools was found to be a useful approach for evaluating in vivo toxicity studies and identifying reliable and sensitive information relevant to regulatory risk assessment of chemicals.

Determination of metoprolol enantiomers in human plasma and saliva samples utilizing microextraction by packed sorbent and liquid chromatography–tandem mass spectrometry

Hatem Elmongy, Hytham Ahmed, Abdel-Aziz Wahbi, Ahmad Amini, Anders Colmsjö and Mohamed Abdel-Rehim*
2016 | Biomed. Chromatogr. | 30 (8) (1309-1317)

A sensitive, accurate and reliable bioanalytical method for the enantioselective determination of metoprolol in
plasma and saliva samples utilizing liquid chromatography–electrospray ionization tandem mass spectrometry was developed
and validated. Human plasma and saliva sampleswere pretreated bymicroextraction by packed sorbent (MEPS) prior to analysis.
A new MEPS syringe form with two inputs was used. Metoprolol enantiomers and internal standard pentycaine (IS) were eluted
from MEPS sorbent using isopropanol after removal of matrix interferences using aliquots of 5% methanol in water. Complete
separation of metoprolol enantiomers was achieved on a Cellulose-SB column (150× 4.6mm, 5 μm) using isocratic elution with
mobile phase 0.1% ammonium hydroxide in hexane–isopropanol (80:20, v/v) with a flow rate of 0.8mL/min. A post-column
solvent-assisted ionization was applied to enhance metoprolol ionization signal in positive mode monitoring (+ES) using 0.5%
formic acid in isopropanol at a flow rate of 0.2mL/min. The total chromatographic run time was 10min for each injection. The
detection of metoprolol in plasma and saliva samples was performed using triple quadrupole tandem mass spectrometer in
+ES under the following mass transitions: m/z 268.08→72.09 for metoprolol and m/z 303.3→154.3 for IS. The linearity range
was 2.5–500 ng/mL for both R- and S-metoprolol in plasma and saliva. The limits of detection and quantitation for both enantiomers
were 0.5 and 2.5 ng/mL respectively, in both matrices (plasma and saliva). The intra- and inter-day precisions were presented
in terms of RSD values for replicate analysis of quality control samples and were <5%; the accuracy of determinations varied from 96 to 99%. The method was able to determine the therapeutic levels of metoprolol enantiomers in both human plasma and saliva samples successfully, which can aid in therapeutic drug monitoring in clinical laboratories.

Observation-Based Assessment of PBDE Loads in Arctic Ocean Waters

Salvado, A.; Sobek, A.; Carrizo, D.; Gustafsson, Ö
2016 | Environ. Sci. Technol. | 50 (2236-2245)

Soil-frost-enabled soil-moisture–precipitation feedback over northern high latitudes

Hagemann, S.; Blome, T.; Ekici, A.; Beer, C.
2016 | Earth Syst. Dynam. | 7 (611-625)

Evaluation of exposure to phthalate esters and DINCH in urine and nails from a Norwegian study population

Giovanoulis G; Alves A; Papadopoulou E; Cousins AP; Schütze A; Koch HM; Haug LS; Covaci A; Magnér J; Voorspoels S
2016 | Environ. Res.
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Phthalate esters (PEs) and 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH) used as additives in numerous consumer products are continuously released into the environment, leading to subsequent human exposure which might cause adverse health effects. The human biomonitoring approach allows the detection of PEs and DINCH in specific populations, by taking into account all possible routes of exposure (e.g. inhalation, transdermal and oral) and all relevant sources (e.g. air, dust, personal care products, diet). We have investigated the presence of nine PE and two DINCH metabolites and their exposure determinants in 61 adult residents of the Oslo area (Norway). Three urine spots and fingernails were collected from each participant according to established sampling protocols. Metabolite analysis was performed by LC-MS/MS. Metabolite levels in urine were used to back-calculate the total exposure to their corresponding parent compound. The primary monoesters, such as monomethyl phthalate (MMP, geometric mean 89.7 ng/g), monoethyl phthalate (MEP, 104.8 ng/g) and mono-n-butyl phthalate (MnBP, 89.3 ng/g) were observed in higher levels in nails, whereas the secondary bis(2-ethylhexyl) phthalate (DEHP) and DINCH oxidative metabolites were more abundant in urine (detection frequency 84–100%). The estimated daily intakes of PEs and DINCH for this Norwegian population did not exceed the established tolerable daily intake and reference doses, and the cumulative risk assessment for combined exposure to plasticizers with similar toxic endpoints indicated no health concerns for the selected population. We found a moderate positive correlation between MEP levels in 3 urine spots and nails (range: 0.56–0.68). Higher frequency of personal care products use was associated with greater MEP concentrations in both urine and nail samples. Increased age, smoking, wearing plastic gloves during house cleaning, consuming food with plastic packaging and eating with hands were associated with higher levels in urine and nails for some of the metabolites. In contrast, frequent hair and hand washing was associated with lower urinary levels of monoisobutyl phthalate (MiBP) and mono(2-ethyl-5-hydroxyhexyl) phthalate (5-OH-MEHP), respectively.

Intercomparison of aerosol extinction profiles retrieved from MAX-DOAS measurements

Friess, U.; Klein Baltink, H.; Beirle, S.; Clemer, K.; Hendrick, F.; Henzing, B.; Irie, H.; de Leeuw, G.; Li, A.; Moerman, M.; van Roozendael, M.; Shaiganfar, R.; Wagner, T.; Wang, Y.; Xie, P.; Yilmaz, S.; Zieger, P.
2016 | Atmos. Meas. Tech. | 9 (3205-3222)

A first direct intercomparison of aerosol vertical profiles from Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations, performed during the Cabauw Intercomparison Campaign of Nitrogen Dioxide measuring Instruments (CINDI) in summer 2009, is presented. Five out of 14 participants of the CINDI campaign reported aerosol extinction profiles and aerosol optical thickness (AOT) as deduced from observations of differential slant column densities of the oxygen collision complex (O4) at different elevation angles. Aerosol extinction vertical profiles and AOT are compared to backscatter profiles from a ceilometer instrument and to sun photometer measurements, respectively. Furthermore, the near-surface aerosol extinction coefficient is compared to in situ measurements of a humidity-controlled nephelometer and dry aerosol absorption measurements. The participants of this intercomparison exercise use different approaches for the retrieval of aerosol information, including the retrieval of the full vertical profile using optimal estimation and a parametrised approach with a prescribed profile shape. Despite these large conceptual differences, and also differences in the wavelength of the observed O4 absorption band, good agreement in terms of the vertical structure of aerosols within the boundary layer is achieved between the aerosol extinction profiles retrieved by the different groups and the backscatter profiles observed by the ceilometer instrument. AOTs from MAX-DOAS and sun photometer show a good correlation (R>0.8), but all participants systematically underestimate the AOT. Substantial differences between the near-surface aerosol extinction from MAX-DOAS and from the humidified nephelometer remain largely unresolved.

Calcium enrichment in sea spray aerosol particles

Salter, M.; Hamacher-Barth, E.; Leck, C.; Werner, J.; Johnson, C.; Riipinen, I.; Nilsson, D.; Zieger, P.
2016 | Geophys Res Lett

Sea spray aerosol particles are an integral part of the Earth's radiation budget. To date, the inorganic composition of nascent sea spray aerosol particles have widely been assumed to be equivalent to the inorganic composition of seawater. Here we challenge this assumption using a laboratory sea spray chamber containing both natural and artificial seawater, as well as with ambient aerosol samples collected over the central Arctic Ocean during summer. We observe significant enrichment of calcium in submicrometer (<1μm in diameter) sea spray aerosol particles when particles are generated from both seawater sources in the laboratory as well as in the ambient aerosols samples. We also observe a tendency for increasing calcium enrichment with decreasing particle size. Our results suggest that calcium enrichment in sea spray aerosol particles may be environmentally significant with implications for our understanding of sea spray aerosol, its impact on Earth's climate, as well as the chemistry of the marine atmosphere.

Comprehensive Study of Human External Exposure to Organophosphate Flame Retardants via Air, Dust, and Hand Wipes: The Importance of Sampling and Assessment Strategy.

Xu F; Giovanoulis G; van Waes S; Padilla-Sanchez JA; Papadopoulou E; Magnér J; Haug LS; Neels H; Covaci A
2016 | Environ. Sci. Technol.
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We compared the human exposure to organophosphate flame retardants (PFRs) via inhalation, dust ingestion, and dermal absorption using different sampling and assessment strategies. Air (indoor stationary air and personal ambient air), dust (floor dust and surface dust), and hand wipes were sampled from 61 participants and their houses. We found that stationary air contains higher levels of ΣPFRs (median = 163 ng/m3, IQR = 161 ng/m3) than personal air (median = 44 ng/m3, IQR = 55 ng/m3), suggesting that the stationary air sample could generate a larger bias for inhalation exposure assessment. Tris(chloropropyl) phosphate isomers (ΣTCPP) accounted for over 80% of ΣPFRs in both stationary and personal air. PFRs were frequently detected in both surface dust (ΣPFRs median = 33 100 ng/g, IQR = 62 300 ng/g) and floor dust (ΣPFRs median = 20 500 ng/g, IQR = 30 300 ng/g). Tris(2-butoxylethyl) phosphate (TBOEP) accounted for 40% and 60% of ΣPFRs in surface and floor dust, respectively, followed by ΣTCPP (30% and 20%, respectively). TBOEP (median = 46 ng, IQR = 69 ng) and ΣTCPP (median = 37 ng, IQR = 49 ng) were also frequently detected in hand wipe samples. For the first time, a comprehensive assessment of human exposure to PFRs via inhalation, dust ingestion, and dermal absorption was conducted with individual personal data rather than reference factors of the general population. Inhalation seems to be the major exposure pathway for ΣTCPP and tris(2-chloroethyl) phosphate (TCEP), while participants had higher exposure to TBOEP and triphenyl phosphate (TPHP) via dust ingestion. Estimated exposure to ΣPFRs was the highest with stationary air inhalation (median =34 ng·kg bw–1·day–1, IQR = 38 ng·kg bw–1·day–1), followed by surface dust ingestion (median = 13 ng·kg bw–1·day–1, IQR = 28 ng·kg bw–1·day–1), floor dust ingestion and personal air inhalation. The median dermal exposure on hand wipes was 0.32 ng·kg bw–1·day–1 (IQR = 0.58 ng·kg bw–1·day–1) for ΣTCPP. The selection of sampling and assessment strategies could significantly affect the results of exposure assessment.

A proposed framework for the systematic review and integrated assessment (SYRINA) of endocrine disrupting chemicals

Laura N Vandenberg; Marlene Ågerstrand; Anna Beronius; Claire Beausoleil; Åke Bergman; Lisa A Bero; Carl-Gustaf Bornehag; C Scott Boyer; Glinda S Cooper; Ian Cotgreave; David Gee; Philippe Grandjean; Kathryn Z Guyton; Ulla Hass; Jerrold J Heindel; Susan Jobling; Karen A Kidd; Andreas Kortenkamp; Malcolm R Macleod; Olwenn V Martin; Ulf Norinder; Martin Scheringer; Kristina A Thayer; Jorma Toppari; Paul Whaley; Tracey J Woodruff; Christina Rudén
2016 | Environ Health | 15 (74) (1-19)

Background
The issue of endocrine disrupting chemicals (EDCs) is receiving wide attention from both the scientific and regulatory communities. Recent analyses of the EDC literature have been criticized for failing to use transparent and objective approaches to draw conclusions about the strength of evidence linking EDC exposures to adverse health or environmental outcomes. Systematic review methodologies are ideal for addressing this issue as they provide transparent and consistent approaches to study selection and evaluation. Objective methods are needed for integrating the multiple streams of evidence (epidemiology, wildlife, laboratory animal, in vitro, and in silico data) that are relevant in assessing EDCs.

Methods
We have developed a framework for the systematic review and integrated assessment (SYRINA) of EDC studies. The framework was designed for use with the International Program on Chemical Safety (IPCS) and World Health Organization (WHO) definition of an EDC, which requires appraisal of evidence regarding 1) association between exposure and an adverse effect, 2) association between exposure and endocrine disrupting activity, and 3) a plausible link between the adverse effect and the endocrine disrupting activity.

Results
Building from existing methodologies for evaluating and synthesizing evidence, the SYRINA framework includes seven steps: 1) Formulate the problem; 2) Develop the review protocol; 3) Identify relevant evidence; 4) Evaluate evidence from individual studies; 5) Summarize and evaluate each stream of evidence; 6) Integrate evidence across all streams; 7) Draw conclusions, make recommendations, and evaluate uncertainties. The proposed method is tailored to the IPCS/WHO definition of an EDC but offers flexibility for use in the context of other definitions of EDCs.

Conclusions
When using the SYRINA framework, the overall objective is to provide the evidence base needed to support decision making, including any action to avoid/minimise potential adverse effects of exposures. This framework allows for the evaluation and synthesis of evidence from multiple evidence streams. Finally, a decision regarding regulatory action is not only dependent on the strength of evidence, but also the consequences of action/inaction, e.g. limited or weak evidence may be sufficient to justify action if consequences are serious or irreversible.

Road salt emissions: A comparison of measurements and modelling using the NORTRIP road dust emission model

Denby, B.R.; Ketzel, M.; Ellermann, T.; Stojiljkovic, A.; Kupiainen, K.; Niemi, J.V.; Norman, M.; Johansson, C.; Gustafsson, M.; Blomqvist, G.; Janhäll, S.; Sundvor, I.
2016 | Atmos Environ | 141 (508-522)

De-icing of road surfaces is necessary in many countries during winter to improve vehicle traction. Large
amounts of salt, most often sodium chloride, are applied every year. Most of this salt is removed through
drainage or traffic spray processes but a certain amount may be suspended, after drying of the road
surface, into the air and will contribute to the concentration of particulate matter. Though some measurements
of salt concentrations are available near roads, the link between road maintenance salting
activities and observed concentrations of salt in ambient air is yet to be quantified. In this study the
NORTRIP road dust emission model, which estimates the emissions of both dust and salt from the road
surface, is applied at five sites in four Nordic countries for ten separate winter periods where daily mean
ambient air measurements of salt concentrations are available. The model is capable of reproducing
many of the salt emission episodes, both in time and intensity, but also fails on other occasions. The
observed mean concentration of salt in PM10, over all ten datasets, is 4.2 mg/m3 and the modelled mean is
2.8 mg/m3, giving a fractional bias of 0.38. The RMSE of the mean concentrations, over all 10 datasets, is
2.9 mg/m3 with an average R2 of 0.28. The mean concentration of salt is similar to the mean exhaust
contribution during the winter periods of 2.6 mg/m3. The contribution of salt to the kerbside winter mean
PM10 concentration is estimated to increase by 4.1 ± 3.4 mg/m3 for every kg/m2 of salt applied on the road
surface during the winter season. Additional sensitivity studies showed that the accurate logging of salt
applications is a prerequisite for predicting salt emissions, as well as good quality data on precipitation. It
also highlights the need for more simultaneous measurements of salt loading together with ambient air
concentrations to help improve model parameterisations of salt and moisture removal processes.

Effect of hygroscopic growth on the aerosol light-scattering coefficient: A review of measurements, techniques and error sources

Titos, G.; Cazorla, A.; Zieger, P.; Andrews, E.; Lyamani, H.; Granados-Munoz, M.J.; Olmo, F.J.; Alados-Arboledas, L
2016 | Atmos Environ | 141 (494-507)

Knowledge of the scattering enhancement factor, f(RH), is important for an accurate description of direct aerosol radiative forcing. This factor is defined as the ratio between the scattering coefficient at enhanced relative humidity, RH, to a reference (dry) scattering coefficient. Here, we review the different experimental designs used to measure the scattering coefficient at dry and humidified conditions as well as the procedures followed to analyze the measurements. Several empirical parameterizations for the relationship between f(RH) and RH have been proposed in the literature. These parameterizations have been reviewed and tested using experimental data representative of different hygroscopic growth behavior and a new parameterization is presented. The potential sources of error in f(RH) are discussed. A Monte Carlo method is used to investigate the overall measurement uncertainty, which is found to be around 20–40% for moderately hygroscopic aerosols. The main factors contributing to this uncertainty are the uncertainty in RH measurement, the dry reference state and the nephelometer uncertainty. A literature survey of nephelometry-based f(RH) measurements is presented as a function of aerosol type. In general, the highest f(RH) values were measured in clean marine environments, with pollution having a major influence on f(RH). Dust aerosol tended to have the lowest reported hygroscopicity of any of the aerosol types studied. Major open questions and suggestions for future research priorities are outlined.

Variability in the sensitivity among model simulations of permafrost and carbon dynamics in the permafrost region between 1960 and 2009

McGuire, A. D.; Koven, C.; Lawrence, D. M.; Clein, J. S.; Xia, J.; Beer, C.; Burke, E.; Chen, G.; Chen, X.; Delire, C.; Jafarov, E.; MacDougall, A. H.; Marchenko, S.; Nicolsky, D; Peng, S.; Rinke, A.; Saito, K.; Zhang, W.; Alkama, R.; Bohn, T. J.; Ciais, P.; Decharme, B; Ekici, A.; Gouttevin, I.; Hajima, T.; Hayes, D. J.; Ji, D.; Krinner, G.; Lettenmaier, D. P.; Luo, Y.; Miller, P. A.; Moore, J. C.; Romanovsky, V.; Schädel, C.; Schaefer, K.; Schuur, E. A. G.; Smith, B.; Sueyoshi, T.; Zhuang, Q.
2016 | Global Biogeochem Cycles | 30 (1015-1037)

A significant portion of the large amount of carbon (C) currently stored in soils of the permafrost region in the Northern Hemisphere has the potential to be emitted as the greenhouse gases CO2 and CH4 under a warmer climate. In this study we evaluated the variability in the sensitivity of permafrost and C in recent decades among land surface model simulations over the permafrost region between 1960 and 2009. The 15 model simulations all predict a loss of near-surface permafrost (within 3 m) area over the region, but there are large differences in the magnitude of the simulated rates of loss among the models (0.2 to 58.8 × 103 km2 yr−1). Sensitivity simulations indicated that changes in air temperature largely explained changes in permafrost area, although interactions among changes in other environmental variables also played a role. All of the models indicate that both vegetation and soil C storage together have increased by 156 to 954 Tg C yr−1 between 1960 and 2009 over the permafrost region even though model analyses indicate that warming alone would decrease soil C storage. Increases in gross primary production (GPP) largely explain the simulated increases in vegetation and soil C. The sensitivity of GPP to increases in atmospheric CO2 was the dominant cause of increases in GPP across the models, but comparison of simulated GPP trends across the 1982–2009 period with that of a global GPP data set indicates that all of the models overestimate the trend in GPP. Disturbance also appears to be an important factor affecting C storage, as models that consider disturbance had lower increases in C storage than models that did not consider disturbance. To improve the modeling of C in the permafrost region, there is the need for the modeling community to standardize structural representation of permafrost and carbon dynamics among models that are used to evaluate the permafrost C feedback and for the modeling and observational communities to jointly develop data sets and methodologies to more effectively benchmark models.

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 70 11
stella.papadopoulou@aces.su.se