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Experiments examining mercury (Hg) toxicity in Daphnia are usually conducted in highly standardized conditions that prevent the formation of biofilm. Although such standardization has many advantages, extrapolation of results to natural conditions and inference of ecological effects is challenging. This is especially true since biofilms can accumulate metals/metalloids and play a key role in their transfer to higher trophic level organisms. In this study, we experimentally tested the effects of spontaneously appearing biofilm in Daphnia cultures on accumulation of Hg and its natural antagonist selenium (Se) in Daphnia magna. We added Hg (in the form of mercury (II) chloride) at two concentrations (0.2 µg/L and 2 µg/L) to experimental microcosms and measured the uptake of Hg and Se by D. magna in the presence and absence of biofilm. To test for consistent and replicable results, we ran two identical experimental sets one week apart. Biofilm presence significantly reduced the accumulation of Hg, while increasing the tissue Se content in D. magna, and these findings were reproducible across experimental sets. These findings indicate that highly standardized tests may not be adequate to predict the bioaccumulation and potential toxicity of metals/metalloids under natural conditions.

Maintaining a steady sample temperature when analyzing real-time samples in the field is crucial for Membrane Introduction Mass Spectrometry (MIMS). Diffusion through the membrane interface is temperature dependent, and sample temperature might vary depending on the sample source. In order to reduce this source of inaccuracy, an in-field and online continuous monitoring system based on (MIMS) coupled with a heat exchanger and in-line standard addition was developed for monitoring volatile organic compounds (VOC) in actual field samples. Parametric studies of the heat exchanger have been conducted in the laboratory. In order to maintain control on instrumental signal drift during continuous, long-term analysis periods, the system used continuous infusion of internal standard (tuloene-d8) into the sample stream and also provided the possibility to infuse, in the same way, an analyte for standard addition calibration. This set-up has been utilized in the field for analyzing both natural water sources and heavily polluted process water. The system was demonstrated to offer a rapid method for quantifying volatile hazardous pollutants in aqueous matrices with good time-resolution. This work was supported in part by funding from Statoil ASA (Grand No 4502457485). This is an electronic copy of an article originally published as: Martinsen, M.R., Davey, N.G., Bell, R.J., Krogh, E.T., Gill, C.G., Mikkelsen, Ø., & Schmid, R. (2020). A field portable membrane introduction mass spectrometer with in-line standard infusion and sample heat exchanger for real-time monitoring of volatile organic compounds in aqueous samples. Environmental Chemistry and Ecotoxicology, 2, 168-174. https://doi.org/10.1016/j.enceco.2020.09.003 https://viurrspace.ca/bitstream/handle/10613/23379/KroghGillECE2020.pdf?sequence=3

Despite being a remote location, the Arctic is a major receptor for anthropogenic pollution transported from the mid-latitudes. Vegetation and underlying organic soils in the Norwegian Arctic, Svalbard were used to study the occurrences of polychlorinated biphenyls (PCBs) and trace elements. In this study, current concentrations of PCBs and trace elements, namely, Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, S, Sb, U and Zn in the terrestrial compartments of Svalbard are presented. Samples were collected from Adventdalen near Longyearbyen and from areas in proximity to Ny-Ålesund. There was significant variability in soil organic matter (SOM) among the soils analysed (5.0%–72.1%), with the highest values detected in Ny-Ålesund. The concentrations of Al, As, Cr Cu, Fe, Pb and Ni were associated with the geology of the local bedrock. The concentrations of all elements, except for Cd, Hg and Zn, were higher in soils than those in the overlying vegetation layers. Mean concentrations of ∑PCBs were significantly higher in vegetation (6.90 ± 0.81 ng g−1 dw) than the underlying organic soils (3.70 ± 0.36 ng g−1 dw). An inverse correlation of PCBs with the elements originating from the local bedrock indicated that their concentrations were potentially impacted by atmospheric deposition. PCBs and Cd were strongly associated, proposing a potential concomitant source of origin in Svalbard. Concentrations of PCBs and trace elements measured herein were below the proposed guidelines for Norwegian soil quality. Trace elements and polychlorinated biphenyls (PCBs) in terrestrial compartments of Svalbard, Norwegian Arctic © 2019 The Authors. Published by Elsevier B.V. Open Access CC BY-NC-ND 4.0

An automatic trace metal monitoring station (ATMS) have been implemented in the river bank of the Deule canal in the city of Auby (northern France), in the vicinity of metallurgical industries that have heavily polluted sediments, in Cd, Pb and Zn. Additionally, the fluvial traffic in this river is intense and surface sediments are resuspended several times per day. This paper is the following part of that published recently (Superville et al., 2014) in this journal. The main purpose of this paper is to present new information on diel and seasonal variations of trace metals in the Deule River and highlight the potential role of sediments in the contamination of the water column. To this end, Cd, Zn and Pb were monitored at a high frequency (~ 1 h − 1 ) by voltammetry, distinguishing an electrolabile and an acid-leachable fraction. Our measurements revealed that (i) acid-leachable Cd is mainly bound to light particles such as clays and carbonates and its daily behaviour does not really depend on the intensity of sediment remobilisation process; (ii) acid-leachable Pb and Zn exhibit some seasonal variations which are explained here, suggesting they should at least partly depend on the ageing of hydrous ferric oxides in the sediments; (iii) in spring, the electrolability of Zn increases in agreement with the biological activity that may break some strong association between Zn and ligands and/or particles (e.g., organic matter, hydrous ferric oxides, etc.). This trend is observed for electrolabile Pb later in summer, but on a smaller scale since this metal is generally more strongly scavenged and less labile than Zn; and (iv) electrolabile Mn concentrations increase during the day due to desorption process of resuspended sediment particles in the water.

Study Design Literature review Objective The aim of this thesis is to compare the main classification systems available for classifying acute subaxial cervical spinal injury and compare their relative strengths and weaknesses, especially in their ability to guide treatment and predict prognosis. Methods A PICO question was formulated and used to select search terms. The search terms were used to search the online database Pubmed/Medline for English language review articles less than 10 years old. These were evaluated based on their abstracts and articles relevant to the PICO question were selected. The final 9 articles were studied and their bibliographies were searched for relevant secondary articles. Results Five main classification systems for acute subaxial cervical trauma were found (Holdsworth's classification, Allen's classification, Harris' classification, the subaxial cervical spine injury classification system (SLIC) and the cervical spine injury severity score (CSISS)). Conclusion By comparing the classification systems, it is evident that older classification systems (Holdsworth, Allen et al and Harris et al) have focused on the mechanisms of injury while newer classification systems (Vaccaro et al, Moore et al) have discarded this in favour of radiological findings and, in the case of Vaccaro et al, neurologic status. Comparisons of the classification systems show that there are clear advantages to the system presented by Vaccaro et al (SLIC scale) compared to previous systems because it may be used to guide treatment, however it has lower reliability and validity compared to the Allen and Harris systems. The CSISS has a higher interrater and intrarater reliability than the SLIC scale but is not suitable for guiding treatment for injuries with scores

Voltammetric procedures for trace metals analysis in polluted natural waters using homemade bare gold-disk microelectrodes of 25- and 125-μ m diameters have been determined. In filtered seawater samples, square wave anodic stripping voltammetry (SWASV) with a frequency of 25 Hz is applied for analysis, whereas in unfiltered contaminated river samples, differential pulse anodic stripping voltammetry (DPASV) gave more reliable results. The peak potentials of the determined trace metals are shifted to more positive values compared to mercury drop or mercury-coated electrodes, with Zn always displaying 2 peaks, and Pb and Cd inversing their positions. For a deposition step of 120 s at − 1.1 V, without stirring, the 25-μ m gold-disk microelectrode has a linear response for Cd, Cu, Mn, Pb and Zn from 0.2 μ g L− 1 (1 μ g L− 1 for Mn) to 20 μ g L− 1 (30 μ g L− 1 for Zn, Pb and 80 μ g L− 1 for Mn). Under the same analytical conditions, the 125-μ m gold-disk microelectrode shows linear behaviour for Cd, Cu, Pb and Zn from 1 μ g L− 1 (5 μ g L− 1 for Cd) to 100 μ g L− 1 (200 μ g L− 1 for Pb). The sensitivity of the 25-μ m electrode varied for different analytes from 0.23 (&plusmn ; ; 0.5%, Mn) to 4.83 (&plusmn ; ; 0.9%, Pb) nA L μ mol− 1, and sensitivity of the 125-μ m electrode varied from 1.48 (&plusmn ; ; 0.7%, Zn) to 58.53 (&plusmn ; ; 1.1%, Pb nA L μ mol− 1. These microelectrodes have been validated for natural sample analysis by use in an on-site system to monitor Cu, Pb and Zn labile concentrations in the De&ucirc ; ; le River (France), polluted by industrial activities. First results obtained on sediment core issued from the same location have shown the ability of this type of microelectrode for in situ measurements of Pb and Mn concentrations in anoxic sediments

International audience; Microelectrodes of silver–copper alloys have been evaluated for use in voltammetric analyses. Increased overpotential towards the hydrogen overvoltage reaction (HER) was found as a function of increased copper content in the silver. A study of oxidizing products by cyclic voltammetry (CV) in NaOH solution showed ten anodic and eight cathodic peaks which are described in the present paper. The behaviour of these alloy electrodes is some-where between pure silver and pure copper electrodes. Differential pulse anodic stripping voltammetry (DPASV) was used to measure zinc, cadmium and lead in ultrapure water only (18 MΩcm), and good linearity was found for all metals (r 2 =0.998) in the range of 0.5 to 5 ppb with a 600-to 1,200-s plating time. It was additionally found that cadmium and lead were better separated on the alloy electrodes compared to pure silver electrodes. Measure-ments of nickel were carried out on alloy electrodes by use of adsorptive differential pulse cathodic stripping voltam-metry (Ad-DPCSV), and good linearity (r 2 =1.000) was found in the range from 0.5 to 5 ppb with an adsorption time of 120 s. The alloy electrodes were also found to be sensitive to nitrate, and good linearity (r 2 =0.997) was found in the range from 1 mg L −1 to 100 mg L −1 using differential pulse voltammetry (DPV) scanning from −450 mV to −1,500 mV. Addition of nitrate in ultrapure water afforded two different peaks related to the successive reductions of nitrate and nitrite. In ammonium buffer solution (pH 8.6) only one peak resulting from reduction of nitrate was observed. Furthermore, the use of alloy electrodes containing 17% Cu was tested in real samples, by installing it in a voltammetric system for monitoring of zinc and lead in a polluted river, the river Deûle, near the town of Douai in northern France. Results were found to be in agreement with parallel measurements carried out by ICP-MS.

Studier indikerer at klima endringer og høyere temperaturer stimulerer transporten, oppdelingen og volatiliteten til polyklorerte bifenyler (PCBer). PCBer er vedvarende organiske forurensninger, som er giftige for miljøet. Det blir frigjort i miljøet, gjennom gammel elektrisk utstyr, maling og andre menneskeskapte kilder, og vil bli transportert via luften, havet og bioakkumulering i levende organismer. Long-range atmospheric transportation (LRAT) er hovedtransporteringsmetoden og den raskeste transporteringen, og er stimulert av økning i temperatur fra klimaendringene. LRAT er også påvirket av værsystemene og høyere vindhastigheter. Økningen i havtemperaturen og PCB eksponering, påvirker næringsnettet og opptaket av PCBer innenfor bioakkumuleringen. Økning i temperatur øker også mengden av den atmosfæriske vanndampen, som produserer mer OH radikaler. OH radikalene reagerer med PCBer og er hovedgrunnen til stoffets degradering i atmosfæren. En mulig økning av den totale mengden PCB i sirkulasjon i miljøet, vil også lede an til flere reaksjoner med ozon, som potensielt kan føre til skade på ozonlaget. Studies indicate that climate change and higher temperature stimulates the transportation, partitioning and volatility of polychlorinated biphenyls (PCBs). PCBs are a persistent organic pollutant, which is toxic for the environment. It gets released into the environment, through old electrical equipment, paint and other anthropogenic sources, and will then be transported via the air, ocean or bioaccumulation through living organisms. Long-range atmospheric transportation (LRAT) is the main source of transport and the fastest, and is stimulated by the increase in temperature due to the climate change. The LRAT is also affected by the weather systems and higher wind speeds. The increase in ocean temperature and PCB exposure, affects the food web and uptake of PCBs in bioaccumulation. Increase in temperature also increases the atmospheric water vapor, which produces more OH radicals. The OH radicals react with the PCBs, and are the main source to its degradation in the atmosphere. A possible increase in the total amount of PCBs in circulation in the environment, will also lead to more reactions with ozone, which could potentially damage the ozone layer.