Investigation of new brominated and organophosphorous flame retardants in Svalbard benthic marine food web; FlammePlank

Project manager Pernilla CarlssonThe aim of this pilot-study was to use silicone rubber-based passive samplers to measure novel brominated flame retardants (nBFRs), polybrominated diphenyl ethers (PBDEs) and dechlorane plus (DP) in seawater and air around Longyearbyen as well as investigate the presence of those compounds in sediment and biota (amphipods, Gammarus spp.) nearby Longyearbyen. Passive samplers require no electricity and provide an integrated picture of the levels of the targeted compounds over time. The results were combined with the sampled sediment and Gammarus spp. to assess concentrations in the environment. Out of all substances under study, PBDE-47 and -99, α- and β- tetrabromoethylcyclohexane (TBECH), syn- and anti-DP were detected in all investigated matrices. Freely dissolved water concentrations of ΣDPs (3 pg/L) were in line with recent Arctic studies, while ΣPBDEs (3 pg/L) were comparable to urban rivers in southern Norway. Nevertheless, for some compounds, especially the lighter and most volatile ones, long-range transport is most likely a more important contribution to observed levels than local sources. For other compounds, e.g. PBDEs, local sources might still play a role for the load of contaminants into the surrounding environment. The present study is the first to report a suit of nBFRs and DPs in Arctic benthic fauna. Many of the nBFRs and DPs were detected in sediment and in the amphipods. We recommend further studies with respect to measurements of concentrations over time, and in other species as well, to better understand whether the nBFRs and DPs are common in the marine environment on Svalbard. We recommend that local sources of flame retardants in remote areas receive more attention in the future.Svalbard miljøvernfondpublishedVersio

Perfluoroalkyl substances in circum-ArcticRangifer: caribou and reindeer

Livers of caribou and reindeer (Rangifer tarandus) from Canada (n = 146), Greenland (n = 30), Svalbard (n = 7), and Sweden (n = 60) were analyzed for concentrations of eight perfluoroalkyl carboxylic acids and four perfluoroalkane sulfonic acids. In Canadian caribou, PFNA (range < 0.01–7.4 ng/g wet weight, ww) and PFUnDA (<0.01–5.6 ng/g ww) dominated, whereas PFOS predominated in samples from South Greenland, Svalbard, and Sweden, although the highest concentrations were found in caribou from Southwest Greenland (up to 28 ng/g ww). We found the highest median concentrations of all PFAS except PFHxS in Akia-Maniitsoq caribou (Southwest Greenland, PFOS 7.2–19 ng/g ww, median 15 ng/g ww). The highest concentrations of ΣPFAS were also found in Akia-Maniitoq caribou (101 ng/g ww) followed by the nearby Kangerlussuaq caribou (45 ng/g ww), where the largest airport in Greenland is situated, along with a former military base. Decreasing trends in concentrations were seen for PFOS in the one Canadian and three Swedish populations. Furthermore, PFNA, PFDA, PFUnDA, PFDoDA, and PFTrDA showed decreasing trends in Canada’s Porcupine caribou between 2005 and 2016. In Sweden, PFHxS increased in the reindeer from Norrbotten between 2003 and 2011. The reindeer from Västerbotten had higher concentrations of PFNA and lower concentrations of PFHxS in 2010 compared to 2002. Finally, we observed higher concentrations in 2010 compared to 2002 (albeit statistically insignificant) for PFHxS in Jämtland, while PFNA, PFDA, PFUnDA, PFDoDA, and PFTrDA showed no difference at all.publishedVersio

Screening av nye PFAS-stoffer 2018

This screening project has focused on the occurrence of conventional andemerging PFASs in terrestrial and marine environments, including the Arctic. Conventional PFASs were found to be wide-spread in the environment and for the first time in Norway reported in wolf, a top predator from the terrestrial environment.Otters living in close proximity to human settlements and preying on the marine food chain,are heavily contaminated with PFASs. Areas where ski-testing activitiesare common are a potential “hotspot” where PFASs can enter the food chain. The difference in PFAS-profile between the samples indicatesthat the diversity in samples are necessary to reveal the complete picture of PFASs in the environment

Selective processes for bioaccumulative up-take of persistent organic pollutants (POPs) in Arctic food webs

The overall aim of the present study was to elucidate selective environmental up-take processes in Arctic food webs that lead to the bioaccumulation of persistent organic pollutants (POP) in food items consumed by Arctic indigenous people. In addition, this study aimed to increase the scientific understanding of the principles behind climate change related influences on transport processes of contaminants. Svalbard and Nuuk, Greenland were chosen as study areas since they represent Arctic conditions, e.g. glaciers, different marine water masses, long-range transport of POPs and few local sources of POPs. In addition, Greenland has a large population of indigenous people consuming traditional food on a daily basis. This thesis is based on field campaigns and empirical data. Legacy pesticides were analysed in water samples from a Greenlandic fjord (paper I). The pesticide distribution indicated that glaciers and snow caps around the fjord are secondary sources of contaminants for the coastal marine environment. Chlordanes were identified as potential indicator compounds for meltwater runoff (paper I). α-hexachlorocyclohexane (α-HCH), trans-, cis- and oxychlordane were chosen for enantiomer selective analyses in zooplankton from Svalbard and Greenlandic traditional food items (paper II, III). The enantiomeric fraction (EF) of α-HCH in the zooplankton was associated to ice cover/break-up. EFs of cis-chlordane were reflected in the deviation from racemic EF among oxychlordane. Chiral pesticides and enantiomer selective analyses are recommended for further studies regarding their potential as marker for changes of the physical environment (paper II). Non-racemic EFs were detected for almost all food samples. Hence, species specific distribution exists, and can be an important factor in future dietary advices. Levels of polychlorinated biphenyls (PCB), polybrominated diphenyl ethers (PBDE), perfluorinated alkylated substances (PFAS) and pesticides were below tolerable daily intake threshold in the food items (paper III, IV). PFAS was detected in the marine mammals, but not in the fish samples, most likely due to industrial processing of the fish (paper IV)

Dentina afetada por cárie : avaliação e desenvolvimento de adesivo experimental

A Odontologia minimamente invasiva tornou-se possível em decorrência do atual avanço alcançado na Odontologia adesiva, e a remoção seletiva do tecido cariado passou a ser recomendada para dentes com lesões de cárie profunda. Tal preparo cavitário preserva a dentina afetada por cárie (DAC), camada mais interna da dentina cariada que é remineralizável. Entretanto, esse substrato apresenta propriedades mecânicas inferiores e diversos estudos relatam uma resistência de união reduzida. O objetivo do presente estudo foi revisar sistematicamente a literatura quanto a resistência da união dos sistemas adesivos à DAC quando comparada à dentina hígida (DH), assim como a influência das variáveis metodológicas dos estudos in vitro. Além disso, desenvolver e caracterizar uma resina adesiva com a incorporação de um fosfato de cálcio, assim como avaliar o potencial de induzir deposição mineral em dentes com DAC. As buscas foram realizadas nas bases de dados PubMed, Scopus, Web of Science e LILACS. Foram incluídos estudos laboratoriais que investigaram a resistência de união à microtração imediata e longitudinal de sistemas adesivos À DAC natural ou artificial, utilizando DH como controle. Oito artigos preencheram os critérios de inclusão, e uma metaregressão foi realizada para a associação das variáveis independentes do modelo com o desfecho de resistência de união. O modelo final com 5 variáveis explicou 75,6% da variabilidade entre os grupos. Todas as variáveis independentes apresentaram influência significativa no desfecho, e a DAC resultou em menor resistência de união. Sendo assim, uma resina adesiva com a incorporação de α-fosfato tricálcico (αTCP) foi desenvolvida e caracterizada. Para a formulação das resinas adesivas, 66,66% em peso de BisGMA, 33,33% em peso de HEMA e um sistema fotoiniciador foram misturados. O αTCP foi adicionado a 2% em peso, originando a resina adesiva teste. Uma resina sem adição de carga foi utilizada como controle. As resinas adesivas foram caracterizadas quanto à taxa de polimerização e grau de conversão, e degradação em solvente. Sessenta dentes permanentes extraídos com lesões de cárie profunda foram submetidos à remoção seletiva do tecido cariado e restaurados utilizando uma das duas resinas adesivas. As amostras foram avaliadas por meio de ensaios imediatos e longitudinais (no decorrer de 6 meses, armazenadas em SBF) de resistência de união à microtração, avaliação da deposição mineral por espectroscopia Raman e dureza Knoop. A dureza Knoop inicial da resina adesiva teste foi maior quando comparada à controle, e não houve diferença entre os grupos em relação ao percentual de variação da dureza Knoop após a imersão em solvente. O grupo teste apresentou maior taxa de polimerização e não houve diferença entres os grupos para o grau de conversão. Não houve diferença entre os grupos para a resistência de união imediata e longitudinal, e ambos os grupos mantiveram estável a resistência de união após 6 meses. A análise da interface em relação à deposição mineral mostrou que houve aumento do conteúdo mineral para os dois grupos. Em relação à dureza Knoop, houve um aumento nos valores após 3 meses, entretanto não houve diferença entre os grupos dentro das diferentes profundidades para cada tempo. Conclui-se que não houve diferença entre os grupos em relação à deposição mineral.The minimally invasive dentistry became possible due to the current advancement in adhesive dentistry, and the selective removal of carious tissue has been recommended for teeth with deep carious lesions. Such cavity preparation preserves the caries-affected dentin (CAD), the inner layer of carious dentin that is remineralizable. However, this substrate presents low mechanical properties and many studies reported reduced bond strength. The objective of this study was to systematically review the literature on the microtensile bond strength (μTBS) of adhesive systems to (CAD) when compared to sound dentin (SD), as well as on the influence of methodological variables of in vitro studies. Also, to develop and characterize an adhesive resin with the incorporation of a calcium phosphate, as well as evaluate the potential to induce mineral deposition in teeth presenting CAD. The electronic databases PubMed, Scopus, ISI Web of Science and LILACS were systematically searched. Were included in vitro studies that assessed the immediate and aged microtensile bond strength of adhesive systems to natural or artificially created CAD in comparison to SD. Eight studies met the inclusion criteria and were included in a linear meta-regression of microtensile bond strength. The fully adjusted model with 5 methodological variables explained 75.6% of the variability among groups. All methodological variables were associated with microtensile bond strength, and bond strength to CAD was lower than to SD. Thus, an adhesive resin with the incorporation of α-tricalcium phosphate (αTCP) was developed and characterized. To formulate the experimental adhesive resins, 66.66 wt% BisGMA, 33.33 wt% HEMA and a photo-initiator system were mixed. The αTCP at 2 wt% was added, yielding the test adhesive resin. An adhesive resin without filler was used as control. The adhesive resins were characterized regarding polymerization kinetics and degree of conversion, and softening in ethanol. Sixty extracted human posterior permanent teeth with deep carious lesions were submitted to selective removal of carious tissue and restored using one of the two adhesive resins. Samples were evaluated by immediate and longitudinal (6 months, storage in SBF) following tests: microtensile bond strength, mineral deposition by Raman spectroscopy and Knoop hardness. The test adhesive resin showed higher initial Knoop hardness than the control one, and there was no difference between the groups for the percentage of variation of Knoop hardness after solvent immersion. The test group showed increased polymerization rate, and there was no difference between groups for degree of conversion. There was no difference between the groups for immediate and longitudinal microtensile bond strength, and the microtensile bond strength of both groups remained stable after the 6 months. The interface analysis regarding mineral deposition showed an increasing in mineral content for both groups. For Knoop hardness, there was an increase after 3 months, however the groups where not significantly different considering depth and time. It could be concluded that there was no difference between control and test adhesive resin for mineral deposition

Chasing equilibrium passive sampling of hydrophobic organic compounds in water

Embargo until 24 January 2021We investigated a combination of approaches to extend the attainment of partition equilibria between silicone passive samplers (samplers) and surface or treated waste water towards more hydrophobic organic compounds (HOC). The aim was to identify the HOC hydrophobicity range for which silicone sampler equilibration in water is feasible within a reasonable sampler deployment period. Equilibrium partitioning of HOC between sampler and water is desirable for a simpler application as a “chemometer”, aiming to compare chemical activity gradients across environmental media (e.g. water, sediment, biota). The tested approaches included a) long sampler exposure periods and high water flow to maximize mass transfer from water to sampler; b) the use of samplers with reduced sheet thicknesses; and c) pre-equilibration of samplers with local bottom sediment, followed by their exposure in surface water at the same sampling site. These approaches were tested at three sites including a fish pond with a low level of pollution, a river impacted by an urban agglomeration and an effluent of municipal wastewater treatment plant. Tested compounds included polychlorinated biphenyls (PCB), polycyclic aromatic hydrocarbons (PAH), DDT, its metabolites and their isomers, hexachlorobenzene (HCB) and polybrominated diphenyl ethers (PBDE). The study shows that samplers with a surface area of 400–800 cm2 consisting of thin (100–500 μm) silicone sheets exposed at sampling rates of 10–40 L d−1 for a time period of up to four months reach partition equilibrium with water for compounds with log Kow ≤ 5.5. Nevertheless, for compounds beyond this limit it is challenging, within a reasonable time period, to reach equilibrium between sampler and water in an open system where water boundary layer resistance controls the mass transfer. For more hydrophobic HOC (log Kow > 6), the kinetic method using performance reference compounds is recommended instead.acceptedVersio

Effects of variability and rate on

The growing prevalence of hybrid and electric vehicles, intermittent renewable en-ergy sources, and other complex power systems has triggered a rapid increase in demand for energy storage. Unlike portable electronic devices, whose batteries can be recharged according to a pre-determined protocol simply by plugging them into the wall, many of these applications are characterized by highly variable charge and demand profiles. The central objective of this work is to assess the impact of power distribution and frequency on battery behavior in order to improve overall system efficiency and lifespan in these variable power applications. We first develop and experimentally verify a model to describe the trade-off be-tween battery charging power and energy stored to assess how varying power input affects battery efficiency. This relationship is influenced both by efficiency losses at high powers and by premature voltage cutoffs, which contribute to incomplete battery charging and discharging. We experimentally study the impact of variable power on battery aging in lead-acid, nickel metal hydride, lithium-ion and lithiu

Unraveling the Relationship between the Concentrations of Hydrophobic Organic Contaminants in Freshwater Fish of Different Trophic Levels and Water Using Passive Sampling

Embargo until 18 June 2021The concentrations of hydrophobic organic compounds (HOCs) in aquatic biota are used for compliance, as well as time and spatial trend monitoring in the aqueous environment (European Union water framework directive, OSPAR). Because of trophic magnification in the food chain, the thermodynamic levels of HOCs, for example, polychlorinated biphenyl congeners, dichlorodiphenyltrichloroethane, and brominated diphenyl ether congeners, in higher trophic level (TL) organisms are expected to be strongly elevated above those in water. This work compares lipid-based concentrations at equilibrium with the water phase derived from aqueous passive sampling (CL⇌water) with the lipid-based concentrations in fillet and liver of fish (CL) at different TLs for three water bodies in the Czech Republic and Slovakia. The CL values of HOCs in fish were near CL⇌water, only after trophic magnification up to TL = 4. For fish at lower TL, CL progressively decreased relative to CL⇌water as KOW of HOCs increased above 106. The CL value decreasing toward the bottom of the food chain suggests nonequilibrium for primary producers (algae), which is in agreement with modeling passive HOC uptake by algae. Because trophic magnification and the resulting CL in fish exhibit large natural variability, CL⇌water is a viable alternative for monitoring HOCs using fish, showing a twofold lower confidence range and requiring less samples.acceptedVersio

Miljøgiftundersøkelser av ørret fra Akerselva og Lysakerelva i 2018

Til sammen 90 ørret fra tre stasjoner i Akerselva og tre stasjoner i Lysakerelva ble analysert for innhold av utvalgte grunnstoffer i gjelle‐ og levervev, omdannede PAH‐forbindelser i galle, samt mikroplast i fordøyelseskanalen. Kobber, arsen, bly, sink, krom og 1‐OH‐pyren viste tegn til økte nivåer i ørret fra nedre deler av en eller begge elver. Konsentrasjonen av omdannet PAH i galle var høyere enn bakgrunnsnivåer. De fleste metaller viste moderate nivåer. Et unntak var sink i gjellevev spesielt nederst i Lysakerelva, og enkelte blyverdier i gjelle og lever i ørret fra Akerselva. I gjennomsnitt ble det funnet mindre enn én mikroplastpartikkel per fisk, og det som ble påvist var hovedsakelig fibre med blå farge