Degradation of naturally produced hydroxylated polybrominated diphenyl ethers in Baltic Sea sediment via reductive debromination

Lindqvist, D; Gustafsson, J
2021 | Environ Sci Pollut Res | 28 (20) (25878-25885)
algae , biodegradation , oh-pbde , pbde , reduction , sediment
Over the last two decades, the occurrence of hydroxylated polybrominated diphenyl ethers (OH-PBDEs) has been observed to be nearly ubiquitous among Baltic Sea filamentous macroalgae. High concentrations are continuously recorded among red, green, and brown filamentous algae. Several of these algae species are ephemeral, and when large parts of the colonies decay at the end of their lifecycles, the OH-PBDEs are expected to largely partition to the sediment. In this study, the fate of OH-PBDEs in Baltic Sea sediment was investigated, with focus on the effect of reductive debromination. During chemical debromination, it was observed that the half-life could differ with as much as two orders of magnitude between a pentabrominated and a tetrabrominated congener. Using collected Baltic Sea sediment, it was further observed that the half-life of spiked pentabrominated OH-PBDEs spanned from a few days up to a few weeks in room temperature. At 4 degrees C, it took 6 months to achieve a 50% decrease in concentration of the fasted degrading congener. Clear differences in selectivity between chemical debromination and debromination in sediment were also observed when studying the major reaction products. Baltic Sea sediment seems to have a good capacity for reducing naturally produced OH-PBDEs.

Photolytically induced changes in composition and volatility of biogenic secondary organic aerosol from nitrate radical oxidation during night-to-day transition

Wu, C; Bell, DM; Graham, EL; Haslett, S; Riipinen, I; Baltensperger, U; Bertrand, A; Giannoukos, S; Schoonbaert, J; El Haddad, I; Prevot, ASH; Huang, W; Mohr, C
2021 | Atmos. Chem. Phys. | 21 (19) (14907-14925)
alpha-pinene , carbonyl nitrates , chemical composition , evaporation kinetics , isoprene oxidation , mass-spectrometer , model , no3 , optical-properties , photolysis

Night-time reactions of biogenic volatile organic compounds (BVOCs) and nitrate radicals (NO3) can lead to the formation of NO3-initiated biogenic secondary organic aerosol (BSOANO(3)). Here, we study the impacts of light exposure on the chemical composition and volatility of BSOANO(3) formed in the dark from three precursors (isoprene, alpha-pinene, and beta-caryophyllene) in atmospheric simulation chamber experiments. Our study represents BSOANO(3) formation conditions where reactions between peroxy radicals (RO2 + RO2) and between RO2 and NO3 are favoured. The emphasis here is on the identification of particle-phase organonitrates (ONs) formed in the dark and their changes during photolytic ageing on timescales of similar to 1 h. The chemical composition of particle-phase compounds was measured with a chemical ionization mass spectrometer with a filter inlet for gases and aerosols (FIGAERO-CIMS) and an extractive electrospray ionization time-of-flight mass spectrometer (EESI-TOF). Volatility information on BSOANO(3) was derived from FIGAERO-CIMS desorption profiles (thermograms) and a volatility tandem differential mobility analyser (VTDMA). During photolytic ageing, there was a relatively small change in mass due to evaporation (< 5 % for the isoprene and alpha-pinene BSOANO3, and 12 % for the beta-caryophyllene BSOANO(3)), but we observed significant changes in the chemical composition of the BSOANO(3). Overall, 48 %, 44 %, and 60 % of the respective total signal for the isoprene, alpha-pinene, and beta-caryophyllene BSOANO(3) was sensitive to photolytic ageing and exhibited decay. The photolabile compounds include both monomers and oligomers. Oligomers can decompose into their monomer units through photolysis of the bonds (e.g. likely O-O) between them. Fragmentation of both oligomers and monomers also happened at other positions, causing the formation of compounds with shorter carbon skeletons. The cleavage of the nitrate functional group from the carbon chain was likely not a main degradation pathway in our experiments. In addition, photolytic degradation of compounds changes their volatility and can lead to evaporation. We use different methods to assess bulk volatilities and discuss their changes during both dark ageing and photolysis in the context of the chemical changes that we observed. We also reveal large uncertainties in saturation vapour pressure estimated from parameterizations for the ON oligomers with multiple nitrate groups. Overall, our results suggest that photolysis causes photodegradation of a substantial fraction of BSOANO(3), changes both the chemical composition and the bulk volatility of the particles, and might be a potentially important loss pathway of BSOANO(3) during the night-to-day transition.

The Atmospheric Aerosol over Western Greece-Six Years of Aerosol Observations at the Navarino Environmental Observatory

Hansson, HC; Tunved, P; Krejci, R; Freud, E; Kalivitis, N; Hennig, T; Maneas, G; Gerasopoulos, E
2021 | ATMOSPHERE | 12 (4)
aerosol , atmosphere , background , long-term , mediterranean , particle size
The Eastern Mediterranean is a highly populated area with air quality problems. It is also where climate change is already noticed by higher temperatures and s changing precipitation pattern. The anthropogenic aerosol affects health and changing concentrations and properties of the atmospheric aerosol affect radiation balance and clouds. Continuous long-term observations are essential in assessing the influence of anthropogenic aerosols on climate and health. We present six years of observations from Navarino Environmental Observatory (NEO), a new station located at the south west tip of Peloponnese, Greece. The two sites at NEO, were evaluated to show the influence of the local meteorology and to assess the general background aerosol possible. It was found that the background aerosol was originated from aged European aerosols and was strongly influenced by biomass burning, fossil fuel combustion, and industry. When subsiding into the boundary layer, local sources contributed in the air masses moving south. Mesoscale meteorology determined the diurnal variation of aerosol properties such as mass and number by means of typical sea breeze circulation, giving rise to pronounced morning and evening peaks in pollutant levels. While synoptic scale meteorology, mainly large-scale air mass transport and precipitation, strongly influenced the seasonality of the aerosol properties.

Source apportionment of methane escaping the subsea permafrost system in the outer Eurasian Arctic Shelf

Steinbach, J; Holmstrand, H; Shcherbakova, K; Kosmach, D; Bruchert, V; Shakhova, N; Salyuk, A; Sapart, CJ; Chernykh, D; Noormets, R; Semiletov, I; Gustafsson, O
2021 | Proc. Natl. Acad. Sci. U.S.A. | 118 (10)
arctic , carbon , carbon cycle/climate change , hydrogen , isotopes/radiocarbon , laptev sea , methane , natural gases , ratio , stable isotope , subsea permafrost , water
The East Siberian Arctic Shelf holds large amounts of inundated carbon and methane (CH4). Holocene warming by overlying seawater, recently fortified by anthropogenic warming, has caused thawing of the underlying subsea permafrost. Despite extensive observations of elevated seawater CH4 in the past decades, relative contributions from different subsea compartments such as early diagenesis, subsea permafrost, methane hydrates, and underlying thermogenic/ free gas to these methane releases remain elusive. Dissolved methane concentrations observed in the Laptev Sea ranged from 3 to 1,500 nM (median 151 nM; oversaturation by similar to 3,800%). Methane stable isotopic composition showed strong vertical and horizontal gradients with source signatures for two seepage areas of delta C-13-CH4 = (-42.6 +/- 0.5)/(-55.0 +/- 0.5) % and delta D-CH4 = (-136.8 +/- 8.0)/(-158.1 +/- 5.5) %, suggesting a thermogenic/ natural gas source. Increasingly enriched delta C-13-CH4 and delta D-CH4 at distance from the seeps indicated methane oxidation. The Delta C-14-CH4 signal was strongly depleted (i.e., old) near the seeps (-993 +/- 19/-1050 +/- 89%). Hence, all three isotope systems are consistent with methane release from an old, deep, and likely thermogenic pool to the outer Laptev Sea. This knowledge of what subsea sources are contributing to the observed methane release is a prerequisite to predictions on how these emissions will increase over coming decades and centuries.

Large seasonal and interannual variations of biogenic sulfur compounds in the Arctic atmosphere (Svalbard; 78.9 degrees N, 11.9 degrees E)

Jang, S; Park, KT; Lee, K; Yoon, YJ; Kim, K; Chung, HY; Jang, E; Becagli, S; Lee, BY; Traversi, R; Eleftheriadis, K; Krejci, R; Hermansen, O
2021 | Atmos. Chem. Phys. | 21 (12) (9761-9777)
aerosol black carbon , boundary layer , dimethyl sulfide , dms , methane sulfonic acid , methanesulfonic-acid , msa , ocean , particle formation , sea-salt-sulfate
Seasonal to interannual variations in the concentrations of sulfur aerosols (< 2.5 mu m in diameter; non seasalt sulfate: NSS-SO42-; anthropogenic sulfate: Anth-SO42-; biogenic sulfate: Bio-SO42-; methanesulfonic acid: MSA) in the Arctic atmosphere were investigated using measurements of the chemical composition of aerosols collected at Ny-angstrom lesund, Svalbard (78.9 degrees N, 11.9 degrees E) from 2015 to 2019. In all measurement years the concentration of NSS-SO42- was highest during the pre-bloom period and rapidly decreased towards summer. During the pre-bloom period we found a strong correlation between NSS-SO42- (sum of Anth-SO42- and Bio-SO42-) and Anth-SO42- . This was because more than 50 % of the NSS-SO(4)(2-)measured during this period was Anth-SO42- , which originated in northern Europe and was subsequently transported to the Arctic in Arctic haze. Unexpected increases in the concentration of Bio-SO42- aerosols (an oxidation product of dimethylsulfide: DMS) were occasionally found during the pre-bloom period. These probably originated in regions to the south (the North Atlantic Ocean and the Norwegian Sea) rather than in ocean areas in the proximity of Ny-angstrom lesund. Another oxidation product of DMS is MSA, and the ratio of MSA to Bio-SO42- is extensively used to estimate the total amount of DMS-derived aerosol particles in remote marine environments. The concentration of MSA during the pre-bloom period remained low, primarily because of the greater loss of MSA relative to Bio-SO42- and the suppression of condensation of gaseous MSA onto particles already present in air masses being transported northwards from distant ocean source regions (existing particles). In addition, the low light intensity during the pre-bloom period resulted in a low concentration of photo-chemically activated oxidant species including OH radicals and BrO; these conditions favored the oxidation pathway of DMS to Bio-SO42- rather than to MSA, which acted to lower the MSA concentration at Ny-angstrom lesund. The concentration of MSA peaked in May or June and was positively correlated with phytoplankton biomass in the Greenland and Barents seas around Svalbard. As a result, the mean ratio of MSA to the DMS-derived aerosols was low (0.09 +/- 0.07) in the pre-bloom period but high (0.32 +/- 0.15) in the bloom and post-bloom periods. There was large interannual variability in the ratio of MSA to Bio-SO42- (i.e., 0.24 +/- 0.11 in 2017, 0.40 +/- 0.14 in 2018, and 0.36 +/- 0.14 in 2019) during the bloom and post-bloom periods. This was probably associated with changes in the chemical properties of existing particles, biological activities surrounding the observation site, and air mass transport patterns. Our results indicate that MSA is not a conservative tracer for predicting DMS-derived particles, and the contribution of MSA to the growth of newly formed particles may be much larger during the bloom and post-bloom periods than during the pre-bloom period.

Dose-dependent toxicological effects in rats following a 90-day dietary exposure to PCB-156 include retinoid disruption

Silva, AV; Chu, I; Feeley, M; Bergman, A; Hakansson, H; Oberg, M
2021 | Toxicol. Lett. | 350 (S163-S163)

nLossFinder-A Graphical User Interface Program for the Nontargeted Detection of DNA Adducts

Sousa, PFM; Martella, G; Aberg, KM; Esfahani, B; Motwani, HV
2021 | Toxics | 9 (4)
data-independent acquisition , dna adducts , environmental monitoring , high-resolution mass spectrometry , matlab
DNA adductomics is a relatively new omics approach aiming to measure known and unknown DNA modifications, called DNA adducts. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has become the most common method for analyzing DNA adducts. Recent advances in the field of mass spectrometry have allowed the possibility to perform a comprehensive analysis of adducts, for instance, by using a nontargeted data-independent acquisition method, with multiple precursor m/z windows as an inclusion list. However, the generated data are large and complex, and there is a need to develop algorithms to simplify and automate the time-consuming manual analysis that has hitherto been used. Here, a graphical user interface (GUI) program was developed, with the purpose of tracking a characteristic neutral loss reaction from tandem mass spectrometry of the nucleoside adducts. This program, called nLossFinder, was developed in the MATLAB platform, available as open-source code. Calf thymus DNA was used as a model for method optimization, and the overall adductomics approach was applied to DNA from amphipods (Monoporeia affinis) collected within the Swedish National Marine Monitoring Program. In the amphipod DNA, over 150 putative adducts were found in comparison to 18 using a manual approach in a previous study. The developed program can improve the processing time for large MS data, as it processes each sample in a few seconds, and hence can be applicable for high-throughput screening of adducts.

Transport and chemistry of isoprene and its oxidation products in deep convective clouds

Bardakov, R; Thornton, JA; Riipinen, I; Krejci, R; Ekman, AML
2021 | Tellus Ser. B-Chem. Phys. Meteorol. | 73 (1)
convective transport of isoprene , deep convective cloud trajectories , epoxide formation , gas-phase , ice , particle formation , photochemical box model , photolysis frequencies , rain forest , secondary organic aerosol , thermodynamic model , tropical upper troposphere , united-states
Deep convective clouds can transport trace gases from the planetary boundary layer into the upper troposphere where subsequent chemistry may impact aerosol particle formation and growth. In this modelling study, we investigate processes that affect isoprene and its oxidation products injected into the upper troposphere by an isolated deep convective cloud in the Amazon. We run a photochemical box model with coupled cloud microphysics along hundreds of individual air parcel trajectories sampled from a cloud-resolving model simulation of a convective event. The box model simulates gas-phase chemical reactions, gas scavenging by liquid and ice hydrometeors, and turbulent dilution inside a deep convective cloud. The results illustrate the potential importance of gas uptake to anvil ice in regulating the intensity of the isoprene oxidation and associated low volatility organic vapour concentrations in the outflow. Isoprene transport and fate also depends on the abundance of lightning-generated nitrogen oxide radicals (NOx = NO + NO2). If gas uptake on ice is efficient and lightning activity is low, around 30% of the boundary layer isoprene will survive to the cloud outflow after approximately one hour of transport, while all the low volatile oxidation products will be scavenged by the cloud hydrometeors. If lightning NOx is abundant and gas uptake by ice is inefficient, then all isoprene will be oxidised during transport or in the immediate outflow region, while several low volatility isoprene oxidation products will have elevated concentrations in the cloud outflow. Reducing uncertainties associated with the uptake of vapours on ice hydrometeors, especially HO2 and oxygenated organics, is essential to improve predictions of isoprene and its oxidation products in deep convective outflows and their potential contribution to new particle formation and growth.

A call for urgent action to safeguard our planet and our health in line with the helsinki declaration

Halonen, JI; Erhola, M; Furman, E; Haahtela, T; Jousilahti, P; Barouki, R; Bergman, A; Billo, NE; Fuller, R; Haines, A; Kogevinas, M; Kolossa-Gehring, M; Krauze, K; Lanki, T; Vicente, JL; Messerli, P; Nieuwenhuijsen, M; Paloniemi, R; Peters, A; Posch, KH; Timonen, P; Vermeulen, R; Virtanen, SM; Bousquet, J; Anto, JM
2021 | Environ. Res. | 193
air pollution , allergy , chemical pollution , climate change , diseases , environmental biodiversity , exposure , nature , planetary health , urbanization
In 2015, the Rockefeller Foundation-Lancet Commission launched a report introducing a novel approach called Planetary Health and proposed a concept, a strategy and a course of action. To discuss the concept of Planetary Health in the context of Europe, a conference entitled: "Europe That Protects: Safeguarding Our Planet, Safeguarding Our Health" was held in Helsinki in December 2019. The conference participants concluded with a need for action to support Planetary Health during the 2020s. The Helsinki Declaration emphasizes the urgency to act as scientific evidence shows that human activities are causing climate change, biodiversity loss, land degradation, overuse of natural resources and pollution. They threaten the health and safety of human kind. Global, regional, national, local and individual initiatives are called for and multidisciplinary and multiT-sectorial actions and measures are needed. A framework for an action plan is suggested that can be modified for local needs. Accordingly, a shift from fragmented approaches to policy and practice towards systematic actions will promote human health and health of the planet. Systems thinking will feed into conserving nature and biodiversity, and into halting climate change. The Planetary Health paradigm - the health of human civilization and the state of natural systems on which it depends -must become the driver for all policies.

Elevated concentrations of mercury and methylmercury in the Gadani shipbreaking area, Pakistan

Kakar, A; Van, LN; Mahmood, Q; Jonsson, S
2021 | Mar. Pollut. Bull. | 165
beaching , gadani , mercury , methylmercury , pakistan , shipbreaking

Gadani shipbreaking area, Pakistan, is the world's third largest shipbreaking unit. However, to date, only a few studies on the environmental impacts of the industry, including mercury (Hg) pollution, have been conducted. To address this, concentrations of total Hg (HgT) and methylmercury (MeHg) were measured in surface sediments collected from the Gadani shipbreaking area as well as a local reference area. The highest concentrations of HgT and MeHg (median +/- interquartile range) were detected in samples from the beach at the yard zone (HgT: 270 +/- 230 mu g kg(-1), MeHg: 0.65 +/- 0.69 mu g kg(-1)), followed by sediment samples from the inter/sub-tidal zone where ships are dismantled (HgT: 20 +/- 5.8 mu g kg(-1), MeHg: 0.043 +/- 0.016 mu g kg(-1)). These concentrations were on average 4-50 and 3-30 times greater than the concentrations of HgT and MeHg, respectively, observed in the reference area. Capsule: Elevated concentrations of total and methylated mercury observed in the Gadani Shipbreaking area sediments.

Per- and polyfluoroalkyl substances (PFASs) in Swedish household dust and exposure of pet cats

Weiss, JM; Jones, B; Koekkoek, J; Bignert, A; Lamoree, MH
2021 | Environ Sci Pollut Res | 28 (29) (39001-39013)
cats , dust , paps , pfas , pfoa , pfos , serum , thyroid
Per- and polyfluoroalkyl substances (PFASs) are used in a wide range of products and have been found ubiquitously in our indoor environment, and there is evidence that exposure to PFAS can lead to adverse endocrine effects, such as thyroid hormone disruption. Pet cats have a high dust intake due to their grooming behavior and have been shown to be a suitable sentinel species for assessment of toddler's exposure. Here we used paired household dust (n=46) and cat serum (n=27) samples to establish whether dust is a relevant exposure pathway to PFASs. An analytical method for PFAS analysis was optimized using a low volume of cat serum samples, combining solid-phase extraction and online sample cleanup. Dust was extracted with methanol by sonication and cleaned up by addition of active carbon. In total, 27 PFASs were analyzed by liquid chromatography/mass spectrometry analysis. The correlation between PFAS levels in dust and serum, serum lipids and thyroid hormone levels, and PFAS levels in dust between different rooms were statistically evaluated. PFOS and PFDA could be quantified in all cat serum samples (median 2300 pg/mL and 430 pg/mL, respectively), followed by PFOA (median 1100 pg/mL), quantified in 96% of the samples. The levels of 6:2 and 8:2 diPAPs were determined in 65% and 92% of the serum samples, respectively, and were an order of magnitude lower (1.4-160 pg/mL). Household dust on the other hand was dominated by 6:2 and 8:2 diPAPs, with a median of 65 ng/g dust and 49 ng/g dust, respectively. PFOS (median 13 ng/g dust) and PFOA (median 9 ng/g dust) were quantified in 93% of the dust samples. Only eight PFASs were detected (>LOD) in at least 50% of the samples of both matrices and could be paired. Significant correlations between cat serum and dust were found for PFOA (r(S)=0.32, p<0.049) and PFUnDA (r(S)=0.55, p<0.001). Significant positive correlations were found between serum total thyroxine (r(S)=0.11, p<0.05) and PFNA and between serum cholesterol and PFHpA (r(S)=0.46, p<0.01), PFUnDA (r(S)=0.40, p<0.05), PFDoDA (r(S)=0.44, p<0.01), and sum PFAS (r(S)=0.48, p<0.01). In conclusion, this study confirmed that dust is a relevant exposure pathway for the ingestion of some PFASs for cats, and the serum levels of PFASs could be of relevance for the cat's health.

Introducing a nested multimedia fate and transport model for organic contaminants (NEM)

Breivik, K; Eckhardt, S; McLachlan, MS; Wania, F
2021 | Environ. Sci.-Process Impacts | 23 (8) (1146-1157)
atmospheric transport , environmental fate , global fractionation , historical emission inventory , long range transport , mass-balance models , polybrominated diphenyl ethers , polychlorinated-biphenyls pcbs , polycyclic aromatic hydrocarbons , temporal trends
Some organic contaminants, including the persistent organic pollutants (POPs), have achieved global distribution through long range atmospheric transport (LRAT). Regulatory efforts, monitoring programs and modelling studies address the LRAT of POPs on national, continental (e.g. Europe) and/or global scales. Whereas national and continental-scale models require estimates of the input of globally dispersed chemicals from outside of the model domain, existing global-scale models either have relatively coarse spatial resolution or are so computationally demanding that it limits their usefulness. Here we introduce the Nested Exposure Model (NEM), which is a multimedia fate and transport model that is global in scale yet can achieve high spatial resolution of a user-defined target region without huge computational demands. Evaluating NEM by comparing model predictions for PCB-153 in air with measurements at nine long-term monitoring sites of the European Monitoring and Evaluation Programme (EMEP) reveals that nested simulations at a resolution of 1 degrees x 1 degrees yield results within a factor of 1.5 of observations at sites in northern Europe. At this resolution, the model attributes more than 90% of the atmospheric burden within any of the grid cells containing an EMEP site to advective atmospheric transport from elsewhere. Deteriorating model performance with decreasing resolution (15 degrees x 15 degrees, 5 degrees x 5 degrees and 1 degrees x 1 degrees), manifested by overestimation of concentrations across most of northern Europe by more than a factor of 3, illustrates the effect of numerical diffusion. Finally, we apply the model to demonstrate how the choice of spatial resolution affect predictions of atmospheric deposition to the Baltic Sea. While we envisage that NEM may be used for a wide range of applications in the future, further evaluation will be required to delineate the boundaries of applicability towards chemicals with divergent fate properties as well as in environmental media other than air.

Contact information

Visiting addresses:

Geovetenskapens Hus,
Svante Arrhenius väg 8, Stockholm

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

Mailing address:
Department of Environmental Science
Stockholm University
106 91 Stockholm

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