Comparing total and accessible concentrations of hydrophobic organic contaminants in sediments and suspended particulate matter in the Danube River

Contamination of aquatic ecosystems by hydrophobic organic contaminants (HOCs) is often assessed based on their concentrations in riverbed sediment and suspended particulate matter (SPM). However, total HOC concentration (CTOT) in sediment or SPM is of limited value for evaluating the exposure of benthic or pelagic organisms. The accessible HOC concentration (CAS) presents a useful parameter quantifying the overall pool of HOC in sediment or SPM available for fast partitioning to the water phase or biota. We applied a novel approach of ex situ sequential equilibrium partitioning with silicone elastomer sampler at a high sampler/SPM phase ratio to measure CAS of HOC in SPM from the Danube River. We compared CTOT and CAS in SPM and surface layer sediment collected at the same sites to evaluate whether HOC monitoring in the two matrices provides equivalent information on environmental quality. At most sites, there was a good agreement and correlation of organic carbon (OC)-normalised CTOT in SPM and sediment for polychlorinated biphenyls (PCBs) and the majority of organochlorine pesticides (OCPs). In contrast, CTOT of polycyclic aromatic hydrocarbons (PAHs) in SPM were up to a factor 10 lower in SPM than in sediment. Site-specific differences of OC-normalised CAS concentrations in SPM and sediments were observed for PCBs and OCPs, with accessibility mostly lower in SPM than in sediment. The highest accessibility in SPM was observed for PCBs, ranging between 15 and 30%. The accessibility of OCPs varied from 0 to 23%. SPM and riverbed sediment samples provide complementary but not mutually interchangeable information on HOC contamination.acceptedVersio

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

Mobile dynamic passive sampling of trace organic compounds: Evaluation of sampler performance in the Danube River

Embargo until 15 September 2020A “dynamic” passive sampling (DPS) device, consisting of an electrically driven large volume water pumping device coupled to a passive sampler exposure cell, was designed to enhance the sampling rate of trace organic compounds. The purpose of enhancing the sampling rate was to achieve sufficient method sensitivity, when the period available for sampling is limited to a few days. Because the uptake principle in the DPS remains the same as for conventionally-deployed passive samplers, free dissolved concentrations can be derived from the compound uptake using available passive sampler calibration parameters. This was confirmed by good agreement between aqueous concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) derived from DPS and conventional caged passive sampler. The DPS device enhanced sampling rates of compounds that are accumulated in samplers under water boundary layer control (WBL) more than five times compared with the conventionally deployed samplers. The DPS device was deployed from a ship cruising downstream the Danube River to provide temporally and spatially integrated concentrations. A DPS-deployed sampler with surface area of 400 cm2 can reach sampling rates up to 83 L d−1. The comparison of three passive samplers made of different sorbents and co-deployed in the DPS device, namely silicone rubber (SR), low density polyethylene (LDPE) and SDB-RPS Empore™ disks showed a good correlation of surface specific uptake for compounds that were sampled integratively during the entire exposure period. This provided a good basis for a cross-calibration between the samplers. The good correlation of free dissolved PAHs, PCBs and HCB concentration estimates obtained using SR and LDPE confirmed that both samplers are suitable for the identification of concentration gradients and trends in the water column. We showed that the differences in calculated aqueous concentrations between sampler types are mainly associated with different applied uptake models.acceptedVersio

® ® ® ® passive sampling devices

Abstract The use of passive sampling techniques to monitor water quality offers a number of advantages over conventional grab or spot sampling methods. Recently, a passive sampling device -Chemcatcher ® has been developed for the measurement of a broad range of priority organic and inorganic pollutants. The device uses a common design with interchangeable receiving phases and membranes, depending upon application. There are two designs of housing available for the Chemcatcher ® . The samplers were deployed at two sites in Portsmouth Harbour (Portsmouth, UK) for several 14-day periods. Three replicates of the Chemcatcher ® sampler were deployed at each site. Two different designs of sampler housing were used and compared in the trial. During the whole exposure time the water chemistry was carefully monitored. Spot samples were collected regularly during the deployment period and the uptake of selected organic priority pollutants in the passive samplers was compared to the levels found in the spot samples. The samplers provided time-weighted average concentrations of the bioavailable (truly dissolved) fraction of monitored pollutants. Sampling rates at Site 1 (outside the harbour basin) were are almost three times higher than those at Site 2, which was probably caused by the more intense turbulence of water. In comparison with Concentrations of pollutants at Site 1 determined in passive samplers were lower compared to Site 2. Concentrations in water samples at the two sites did not differ significantly, although slightly higher PAH concentrations were determined at Site 1

Topological maps of Kohonen self-organization (som) applied to the study of sediments contaminated with PBDEs : support for climate extremes risk assessment

Riverine sediments, collected during 2012 from ten sites in a mixed land use region of the Serbian were analysed for seven emergent PBDE congeners. All PBDEs were detected in sediments with the total concentrations range from 0.52 µg/kg (Ratno Ostrvo) to 31.19 µg/kg (Neštin) with mean levels of 8.08 µg/kg and median of 3.14 µg/kg. The classification of data by Kohonen's self-organizing maps (SOM) allowed understanding and visualizing the spatial distribution of samples. Principal component analysis (PCA) was used for validating the obtained results. Correlations and relationships between the samples and the variables can be easily visualized using the viewing of SOM planes of components. The results have highlighted the dependencies between the different PBDEs and the classification of studied sediments into three classes into function of ten stations coring and their pollution levels

On the Relationship Between the Optical Emission-Line and X-ray Luminosities in Seyfert 1 Galaxies

We have explored the relationship between the [O III] $\lambda$5007 and the 2--10 keV luminosities for a sample of Broad- and Narrow-Line Seyfert 1 galaxies (BLSy1 and NLSy1, respectively). We find that both types of Seyferts span the same range in luminosity and possess similar [O III]/X-ray ratios. The NLSy1s are more luminous than BLSy1s, when normalized to their central black hole masses, which is attributed to higher mass accretion rates. However, we find no evidence for elevated [O III]/X-ray ratios in NLSy1s, which would have been expected if they had excess EUV continuum emission compared to BLSy1s. Also, other studies suggest that the gas in narrow-line regions (NLR) of NLSy1s and NLSy1s span a similar range in ionization, contrary to what is expected if those of the former are exposed to a stronger flux of EUV radiation. The simplest interpretation is that, like BLSy1s, a large EUV bump is not present in NLSy1s. However, we show that the [OIII]/X-ray ratio can be lowered as a result of absorption of the ionizing continuum by gas close to the central source, although there is no evidence that intrinsic line-of-sight absorption is more common among NLSy1s, as would be expected if there were a larger amount of circumnuclear gas. Other possible explanations include: 1) anisotropic emission of the ionizing radiation, 2) higher gas densities in the NLR of NLSy1s, resulting in lower average ionization, or 3) the presence of strong winds in the the nuclei of NLSy1s which may drive off much of the gas in the narrow-line region, resulting in lower cover fraction and weaker [O III] emission.Comment: 18 pages, including 3 figures, 2 tables. Accepted for publication in The Astrophysical Journa

Inter-laboratory mass spectrometry dataset based on passive sampling of drinking water for non-target analysis

Non-target analysis (NTA) employing high-resolution mass spectrometry is a commonly applied approach for the detection of novel chemicals of emerging concern in complex environmental samples. NTA typically results in large and information-rich datasets that require computer aided (ideally automated) strategies for their processing and interpretation. Such strategies do however raise the challenge of reproducibility between and within different processing workflows. An effective strategy to mitigate such problems is the implementation of inter-laboratory studies (ILS) with the aim to evaluate different workflows and agree on harmonized/standardized quality control procedures. Here we present the data generated during such an ILS. This study was organized through the Norman Network and included 21 participants from 11 countries. A set of samples based on the passive sampling of drinking water pre and post treatment was shipped to all the participating laboratories for analysis, using one pre-defined method and one locally (i.e. in-house) developed method. The data generated represents a valuable resource (i.e. benchmark) for future developments of algorithms and workflows for NTA experiments

The NORMAN Association and the European Partnership for Chemicals Risk Assessment (PARC): let’s cooperate! [Commentary]

The Partnership for Chemicals Risk Assessment (PARC) is currently under development as a joint research and innovation programme to strengthen the scientific basis for chemical risk assessment in the EU. The plan is to bring chemical risk assessors and managers together with scientists to accelerate method development and the production of necessary data and knowledge, and to facilitate the transition to next-generation evidence-based risk assessment, a non-toxic environment and the European Green Deal. The NORMAN Network is an independent, well-established and competent network of more than 80 organisations in the field of emerging substances and has enormous potential to contribute to the implementation of the PARC partnership. NORMAN stands ready to provide expert advice to PARC, drawing on its long experience in the development, harmonisation and testing of advanced tools in relation to chemicals of emerging concern and in support of a European Early Warning System to unravel the risks of contaminants of emerging concern (CECs) and close the gap between research and innovation and regulatory processes. In this commentary we highlight the tools developed by NORMAN that we consider most relevant to supporting the PARC initiative: (i) joint data space and cutting-edge research tools for risk assessment of contaminants of emerging concern; (ii) collaborative European framework to improve data quality and comparability; (iii) advanced data analysis tools for a European early warning system and (iv) support to national and European chemical risk assessment thanks to harnessing, combining and sharing evidence and expertise on CECs. By combining the extensive knowledge and experience of the NORMAN network with the financial and policy-related strengths of the PARC initiative, a large step towards the goal of a non-toxic environment can be taken