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  • 1. Assefa, Anteneh T.
    et al.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Sundqvist, Kristina L.
    Cato, Ingemar
    Jonsson, Per
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Tysklind, Mats
    Wiberg, Karin
    Temporal Trends of PCDD/Fs in Baltic Sea Sediment Cores Covering the 20th Century2014In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 48, no 2, p. 947-953Article in journal (Refereed)
    Abstract [en]

    The pollution trend of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Baltic Sea region was studied based on depth profiles of PCDD/Fs in sediment cores collected from six-offshore areas, eight coastal sites impacted by industrial/urban emissions, and one coastal reference site. A general trend was observed for the offshore and coastal reference sites with substantial increase in PCDD/F concentrations in the mid-late 1970s and peak levels during 1985-2002. The overall peak year for PCDD/Fs in Baltic Sea offshore areas was estimated (using spline-fit modeling) to 1994 +/- 5 years, and a half-life in sediments was estimated at 29 +/- 11 years. For the industrial/urban impacted coastal sites, the temporal trend was more variable with peak years occurring 1-2 decades earlier compared to offshore areas. The substantial reductions from peak levels (38 +/- 11% and 81 +/- 12% in offshore and coastal areas, respectively) reflect domestic and international actions taken for reduction of the release of PCDD/Fs to the environment. The modeled overall half-life and reductions of PCDD/Fs in offshore Baltic Sea sediment correspond well to both PCDD/F trends in European lakes without any known direct. PCDD/F sources (half-lives 30 and 32 years), and previously modeled reduction in atmospheric deposition of,PCDD/Fs to the Baltic Sea since 1990. These observations support previous findings of a common diffuse source, such as long-range air transport of atmospheric emissions, as the prime source of PCDD/Fs to the Baltic Sea region. The half-life of PCDD/Fs in Baltic Sea offshore sediments was estimated to be approximately 2 and 4-6 times longer than in semirural and urban European air, respectively. This study highlights the need for further international actions to reduce the levels of PCDD/Fs in Baltic Sea air specifically and in European air in general.

  • 2. Assefa, Anteneh T.
    et al.
    Tysklind, Mats
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Sundqvist, Kristina L.
    Geladi, Paul
    Wiberg, Karin
    Assessment of PCDD/F Source Contributions in Baltic Sea Sediment Core Records2014In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 48, no 16, p. 9531-9539Article in journal (Refereed)
    Abstract [en]

    Spatial and temporal trends of sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Baltic Sea were evaluated by positive matrix factorization (PMF) and principal component analysis (PCA). Sediment cores were sampled at eight coastal, one coastal reference, and six offshore sites covering the northern to the southern Baltic Sea. The cores, which covered the period 1919-2010, were sliced into 2-3 cm disks among which 8-11 disks per core (in total 141 disks) were analyzed for all tetra- through octa-CDD/Fs. Identification and apportionment of PCDD/F sources was carried out using PMF. Five stable model PCDD/F congener patterns were identified, which could be associated with six historically important source types: (i) atmospheric background deposition (ABD), (ii) use and production of pentachlorophenol (PCP), (iii) use and production of tetra-chlorophenol (TeCP), (iv) high temperature processes (Thermal), (v) hexa-CDD-related sources (HxCDD), and (vi) chlorine-related sources (Chi), all of which were still represented in the surface layers. Overall, the last four decades of the period 1920-2010 have had a substantial influence on the Baltic Sea PCDD/F pollution, with 88 +/- 7% of the total amount accumulated during this time. The 1990s was the peak decade for all source types except TeCP, which peaked in the 1980s in the northern Baltic Sea and has still not peaked in the southern part. The combined impact of atmospheric-related emissions (ABD and Thermal) was dominant in the open sea system throughout the study period (1919-2010) and showed a decreasing south to north trend (always >80% in the south and >50% in the north). Accordingly, to further reduce levels of PCDD/Fs in the open Baltic Sea ecosystem, future actions should focus on reducing atmospheric emissions.

  • 3.
    Bolinius, Dämien J.
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Löf, Marie F.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Undeman, Emma
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Evaluating the consumption of chemical products and articles as proxies for diffuse emissions to the environment2018In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 20, no 10, p. 1427-1440Article in journal (Refereed)
    Abstract [en]

    In this study we have evaluated the use of consumption of manufactured products (chemical products and articles) in the EU as proxies for diffuse emissions of chemicals to the environment. The content of chemical products is relatively well known. However, the content of articles (products defined by their shape rather than their composition) is less known and currently has to be estimated from chemicals that are known to occur in a small set of materials, such as plastics, that are part of the articles. Using trade and production data from Eurostat in combination with product composition data from a database on chemical content in materials (the Commodity Guide), we were able to calculate trends in the apparent consumption and in-use stocks for 768 chemicals in the EU for the period 2003-2016. The results showed that changes in the apparent consumption of these chemicals over time are smaller than in the consumption of corresponding products in which the chemicals are present. In general, our results suggest that little change in chemical consumption has occurred over the timespan studied, partly due to the financial crisis in 2008 which led to a sudden drop in the consumption, and partly due to the fact that each of the chemicals studied is present in a wide variety of products. Estimated in-use stocks of chemicals show an increasing trend over time, indicating that the mass of chemicals in articles in the EU, that could potentially be released to the environment, is increasing. The quantitative results from this study are associated with large uncertainties due to limitations of the available data. These limitations are highlighted in this study and further underline the current lack of transparency on chemicals in articles. Recommendations on how to address these limitations are also discussed.

  • 4. Carrizo, Daniel
    et al.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Salvadó, Joan A.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Spatial Distributions of DDTs in the Water Masses of the Arctic Ocean2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 14, p. 7913-7919Article in journal (Refereed)
    Abstract [en]

    There is a scarcity of data on the amount and distribution of the organochlorine pesticide dichlorodiphenyltrichloroethane (DDT) and its metabolites in intermediate and deep ocean water masses. Here, the distribution and inventories of DDTs in water of the Arctic shelf seas and the interior basin are presented. The occurrence of Sigma 6DDT (0.10-66 pg L-1) in the surface water was dominated by 4,4'-DDE. In the Central Arctic Ocean increasing concentrations of DDE with depth were observed in the Makarov and Amundsen basins. The increasing concentrations down to 2500 m depth is in accordance with previous findings for PCBs and PBDEs. Similar concentrations of DDT and DDEs were found in the surface water, while the relative contribution of DDEs increased with depth, demonstrating a transformation over time and depth. Higher concentrations of DDTs were found in the European part of the Arctic Ocean; these distributions likely reflect a combination of different usage patterns, transport, and fate of these compounds. For instance, the elevated concentrations of DDTs in the Barents and Atlantic sectors of the Arctic Ocean indicate the northbound Atlantic current as a significant conveyor of DDTs. This study contributes to the very rare data on OCPs in the vast deep-water compartments and combined with surface water distribution across the Arctic Ocean helps to improve our understanding of the large-scale fate of DDTs in the Arctic.

  • 5.
    Castro, Mafalda
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Yuan, Bo
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Athanassiadis, Ioannis
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Asplund, Lillemor
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Partitioning of Chlorinated Paraffins (CPs) to Daphnia magna Overlaps between Restricted and in-Use Categories2018In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 52, no 17, p. 9713-9721Article in journal (Refereed)
    Abstract [en]

    Chlorinated paraffins (CPs) are high-production volume industrial chemicals consisting of n-alkanes (with 10 to 30 carbon atoms in the chain) with chlorine content from 30 to 70% of weight. In Europe, the use of short chain chlorinated paraffins (SCCPs) has been restricted by the Stockholm Convention on POPs due to their PBT (persistent, bioaccumulative and toxic) properties. Medium (MCCPs) and long chain (LCCPs) chlorinated paraffins are used as substitution products. In this work we studied the partitioning behavior of five different CP technical mixtures from the established categories (2 SCCPs, 1 MCCP, 1 LCCP and 1 CP technical mixture covering all categories) using passive dosing, by determining the partitioning coefficient of CP technical mixtures between silicone and water (Ksilicone-water) as well as between organic matter and water (Koc-water). We show that both silicone-water and organic carbon water partition coefficients overlap between different categories of CP technical mixtures. These results indicate that in-use MCCPs and LCCPs may be equally or more bioaccumulative than restricted SCCPs. For the tested mixtures, both chlorine content and carbon chain length showed a significant correlation with both Ksilicone-water and Koc-water.

  • 6.
    Castro, Mafalda
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Yuan, Bo
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bioaccumulation Potential of CPs in Aquatic Organisms: Uptake and Depuration in Daphnia magna2019In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 53, no 16, p. 9533-9541Article in journal (Refereed)
    Abstract [en]

    Chlorinated paraffins (CPs) are industrial chemicals, subdivided into three categories: short chain (SCCPs), medium chain (MCCPs), and long chain (LCCPs) chlorinated paraffins. SCCPs are currently restricted in Europe and North America. MC and LCCPs are being used as substitution products, but there is a knowledge gap concerning their bioaccumulation potential in aquatic organisms. In this work, we performed laboratory bioconcentration (passive uptake) and bioaccumulation (including dietary uptake) experiments with Daphnia magna using five different CP technical substances. All tested CP technical substances were bioaccumulative in D. magna, with log BCF and log BAF values ranging between 6.7-7.0 and 6.5-7.0 (L kg lipid(-1)), respectively. An increase in carbon chain length and an increase in chlorine content (% w/w) of the CP technical substances had significant positive effects on the log BCF and log BAF values. For the different CP technical substances, 50% depuration was achieved after 2 to 10 h when D. magna were transferred to clean media. Our results show that SC, MC, and LCCPs are (very)bioaccumulative in aquatic organisms. We believe these data can aid the ongoing policy discussion concerning the environmental risk posed by CPs.

  • 7.
    Coll, Claudia
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lindim, Claudia
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sohn, Michael D.
    MacLeod, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Prospects for finding Junge variability-lifetime relationships for micropollutants in the Danube river2019In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 21, no 9, p. 1489-1497Article in journal (Refereed)
    Abstract [en]

    Persistence of chemical pollutants is difficult to measure in the field. Junge variability-lifetime relationships, correlating the relative standard deviation of measured concentrations with residence time, have been used to estimate persistence of air pollutants. Junge relationships for micropollutants in rivers could provide evidence that half-lives of compounds estimated from laboratory and field data are representative of half-lives in a specific system, location and time. Here, we explore the hypothesis that Junge relationships could exist for micropollutants in the Danube river using: (1) concentrations of six hypothetical chemicals modeled using the STREAM-EU fate and transport model, and (2) concentrations of nine micropollutants measured in the third Joint Danube Survey (JDS3) combined with biodegradation half-lives reported in the literature. Using STREAM-EU, we found that spatial and temporal variability in modeled concentrations was inversely correlated with half-life for the four micropollutants with half-lives <= 90 days. For these four modeled micropollutants, we found Junge relationships with slopes significantly different from zero in the temporal variability of concentrations at 88% of the 67 JDS3 measurement sites, and in the spatial variability of concentrations on 36% out of 365 modeled days. A Junge relationship significant at the 95% confidence level was not found in the spatial variability of nine micropollutants measured in the JDS3, nor in STREAM-EU-modeled concentrations extracted for the dates and locations of the JDS3. Nevertheless, our model scenarios suggest that Junge relationships might be found in future measurements of spatial and temporal variability of micropollutants, especially in temporal variability of pollutants measured downstream in the Danube river.

  • 8.
    Coll, Claudia
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Raven, Bier
    Li, Zhe
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Langenheder, Silke
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Association between aquatic micropollutant degradation and river sediment bacterial communitiesManuscript (preprint) (Other academic)
  • 9.
    Dahlgren Strååt, Kim
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mörth, Carl-Magnus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Stockholm University, Faculty of Science, Department of Geological Sciences.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Smedberg, Erik
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Undeman, Emma
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Modeling total particulate organic carbon (POC) flows in the Baltic Sea catchment2016In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 128, no 1-2, p. 51-65Article in journal (Refereed)
    Abstract [en]

    The largest input source of carbon to the Baltic Sea catchment is river discharge. A tool for modeling riverine particulate organic carbon (POC) loads on a catchment scale is currently lacking. The present study describes a novel dynamic model for simulating flows of POC in all major rivers draining the Baltic Sea catchment. The processes governing POC input and transport in rivers described in the model are soil erosion, in-stream primary production and litter input. The Baltic Sea drainage basin is divided into 82 sub-basins, each comprising several land classes (e.g. forest, cultivated land, urban areas) and parameterized using GIS data on soil characteristics and topography. Driving forces are temperature, precipitation, and total phosphorous concentrations. The model evaluation shows that the model can predict annual average POC concentrations within a factor of about 2, but generally fails to capture the timing of monthly peak loads. The total annual POC load to the Baltic Sea is estimated to be 0.34 Tg POC, which constitutes circa 7-10 % of the annual total organic carbon (TOC) load. The current lack of field measurements of POC in rivers hampers more accurate predictions of seasonality in POC loads to the Baltic Sea. This study, however, identifies important knowledge gaps and provides a starting point for further explorations of large scale POC mass flows.

  • 10.
    Ek, Caroline
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Holmstrand, Henry
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mustajärvi, Lukas
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Garbaras, Andrius
    Bariseviciute, Ruta
    Sapolaite, Justina
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Karlson, Agnes M. L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Using Compound-Specific and Bulk Stable Isotope Analysis for Trophic Positioning of Bivalves in Contaminated Baltic Sea Sediments2018In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 52, no 8, p. 4861-4868Article in journal (Refereed)
    Abstract [en]

    Stable nitrogen isotopes (delta N-15) are used as indicators of trophic position (TP) of consumers. Deriving TP from delta N-15 of individual amino acids (AAs) is becoming popular in ecological studies, because of lower uncertainty than TP based on bulk delta N-15 (TPbulk). This method would also facilitate biomagnification studies provided that isotope fractionation is unaffected by toxic exposure. We compared TPAA and TPbulk estimates for a sediment-dwelling bivalve from two coastal sites, a pristine and a contaminated. Chemical analysis of PCB levels in mussels, sediments, and pore water confirmed the expected difference between sites. Both methods, but in particular the TPAA underestimated the actual TP of bivalves. Using error propagation, the total uncertainty related to the analytical precision and assumptions in the TP calculations was found to be similar between the two methods. Interestingly, the significantly higher intercept for the regression between T-AA, and TPbulk in the contaminated site compared to the pristine site indicates a higher deamination rate due to detoxification as a result of chronic exposure and a higher N-15 fractionation. Hence, there is a need for controlled experiments on assumptions underlying amino acid-specific stable isotope methods in food web and bimagnification studies.

  • 11.
    Ek, Caroline
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Holmstrand, Henry
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mustajärvi, Lukas
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Garbaras, Andrius
    Bariseviciute, Ruta
    Sapolaite, Justina
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Karlson, Agnes M. L.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Using compound-specific and bulk stable isotope analysis for trophic positioning of bivalves in contaminated Baltic sediments: a field evaluationManuscript (preprint) (Other academic)
  • 12. Jaeger, Anna
    et al.
    Coll, Claudia
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Posselt, Malte
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mechelke, Jonas
    Rutere, Cyrus
    Betterle, Andrea
    Raza, Muhammad
    Mehrtens, Anne
    Meinikmann, Karin
    Portmann, Andrea
    Singh, Tanu
    Blaen, Phillip J.
    Krause, Stefan
    Horn, Marcus A.
    Hollender, Juliane
    Benskin, Jonathan P.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lewandowski, Joerg
    Using recirculating flumes and a response surfacemodel to investigate the role of hyporheic exchangeand bacterial diversity on micropollutant half-lives2019In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895Article in journal (Refereed)
    Abstract [en]

    Enhancing the understanding of the fate of wastewater-derived organic micropollutants in rivers is crucial to improve risk assessment, regulatory decision making and river management. Hyporheic exchange and sediment bacterial diversity are two factors gaining increasing importance as drivers for micropollutant degradation, but are complex to study in field experiments and usually ignored in laboratory tests aimed to estimate environmental half-lives. Flume mesocosms are useful to investigate micropollutant degradation processes, bridging the gap between the field and batch experiments. However, few studies have used flumes in this context. We present a novel experimental setup using 20 recirculating flumes and a response surface model to study the influence of hyporheic exchange and sediment bacterial diversity on half-lives of the anti-epileptic drug carbamazepine (CBZ) and the artificial sweetener acesulfame (ACS). The effect of bedform-induced hyporheic exchange was tested by three treatment levels differing in number of bedforms (0, 3 and 6). Three levels of sediment bacterial diversity were obtained by diluting sediment from the River Erpe in Berlin, Germany, with sand (1 : 10, 1 : 1000 and 1 : 100 000). Our results show that ACS half-lives were significantly influenced by sediment dilution and number of bedforms. Half-lives of CBZ were higher than ACS, and were significantly affected only by the sediment dilution variable, and thus by bacterial diversity. Our results show that (1) the flume-setup is a useful tool to study the fate of micropollutants in rivers, and that (2) higher hyporheic exchange and bacterial diversity in the sediment can increase the degradation of micropollutants in rivers.

  • 13. Jahnke, Annika
    et al.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bergmann, Melanie
    Bräunig, Jennifer
    Landmann, Madlen
    Schäfer, Sabine
    Escher, Beate I.
    Emerging investigator series: effect-based characterization of mixtures of environmental pollutants in diverse sediments2018In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 20, no 12, p. 1667-1679Article in journal (Refereed)
    Abstract [en]

    This study investigated whether cell-based bioassays were suitable to characterize profiles of mixture effects of hydrophobic pollutants in multiple sediments covering remote Arctic and tropical sites to highly populated sites in Europe and Australia. The total contamination was determined after total solvent extraction and the bioavailable contamination after silicone-based passive equilibrium sampling. In addition to cytotoxicity, we observed specific responses in cell-based reporter gene bioassays: activation of metabolic enzymes (arylhydrocarbon receptor: AhR, peroxisome proliferator activated receptor gamma: PPAR) and adaptive stress responses (oxidative stress response: AREc32). No mixture effects were found for effects on the estrogen, androgen, progesterone and glucocorticoid receptors, or they were masked by cytotoxicity. The bioanalytical equivalent concentrations (BEQ) spanned several orders of magnitude for each bioassay. The bioavailable BEQs (passive equilibrium sampling) typically were 10-100 times and up to 420 times lower than the total BEQ (solvent extraction) for the AhR and AREc32 assays, indicating that the readily desorbing fraction of the bioactive chemicals was substantially lower than the fraction bound strongly to the sediment sorptive phases. Contrarily, the bioavailable BEQ in the PPAR assay was within a factor of five of the total BEQ. We identified several hotspots of contamination in Europe and established background contamination levels in the Arctic and Australia.

  • 14.
    Li, Zhe
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Kaserzon, Sarin L.
    Plassmann, Merle M.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gómez Ramos, María José
    Radke, Michael
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    A strategic screening approach to identify transformation products of organic micropollutants along riversManuscript (preprint) (Other academic)
    Abstract [en]

    Many transformation products (TPs) from organic micropollutants are not included in routine monitoring programs due to limited knowledge of their occurrence and fate. An efficient method to identify and prioritize critical compounds in terms of environmental relevance is needed. In this study we applied a strategic screening approach based on a case-control concept to identify TPs with an increasing trend along a stretch in four wastewater-impacted rivers. Time-integrated samples were taken over one week at both ends of a river stretch downstream of a wastewater treatment plant (WWTP) outfall. The screening procedure consisted of three major steps: i) screening for parent compounds (PCs) attenuating along the stretch; ii) prediction of TPs for these PCs; and iii) screening for TPs with an increasing trend along the stretch. In total, 48 organic micropollutants were tentatively identified, of which 32 were decreasing along the stretches. From these PCs, 1315 TPs were predicted and eight out of which were tentatively identified with increasing concentrations along the stretches. Generally, good correlations were observed between the suspect screening results from this study and previous target analysis results on the same samples, suggesting high confidence of our screening approach. The case-control concept was proven efficient and reliable for identifying environmental relevant TPs formed along rivers. 

  • 15.
    Li, Zhe
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Kaserzon, Sarit L.
    Plassmann, Merle M.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gómez Ramos, Maria José
    Radke, Michael
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    A strategic screening approach to identify transformation products of organic micropollutants formed in natural waters2017In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 19, no 4, p. 488-498Article in journal (Refereed)
    Abstract [en]

    Many transformation products (TPs) from organic micropollutants are not included in routine environmental monitoring programs due to limited knowledge of their occurrence and fate. An efficient method to identify and prioritize critical compounds in terms of environmental relevance is needed. In this study, we applied a strategic screening approach based on a case-control concept to identify TPs formed along wastewater-impacted rivers. Time-integrated samples were collected over one week at both ends of a river stretch downstream of a wastewater treatment plant (WWTP) outfall and were analyzed by ultrahigh performance liquid chromatography interfaced with quadrupole time-of-flight mass spectrometry (UHPLC-QToF-MS/MS). The screening procedure of the high-resolution MS (HRMS) datasets consisted of three major steps: (i) screening for parent compounds (PCs) attenuated along the stretch; (ii) prediction of potential TPs from these PCs; and (iii) screening for TPs from this list with an increasing trend along the stretch. In total, 32 PCs decreased along the investigated river stretches. From these PCs, eight TPs had increasing concentrations along the studied stretches and could be tentatively identified. The identification of one TP (benzamide) was confirmed by its corresponding reference standard, while no standards were available for the remaining TPs.

  • 16.
    Li, Zhe
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Radke, Michael
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Fate of pharmaceuticals and their transformation products in four small European rivers receiving treated wastewater2016In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 50, no 11, p. 5614-5621Article in journal (Refereed)
    Abstract [en]

    A considerable knowledge gap exists with respect to the fate and environmental relevance of transformation products (TPs) of polar organic micropollutants in surface water. To narrow this gap we investigated the fate of 20 parent compounds (PCs) and 11 characteristic TPs in four wastewater-impacted rivers. Samples were obtained from time-integrated active sampling as well as passive sampling using polar organic chemical integrative samplers (POCIS). Seventeen out of the 20 PCs were detected in at least one of the rivers. All the PCs except acesulfame, carbamazepine, and fluconazole were attenuated along the studied river stretches, with the largest decrease found in the smallest river which had an intense surface water-pore water exchange. Seven TPs were detected, all of which were already present directly downstream of the WWTP outfall, suggesting that the WWTPs were a major source of TPs to the recipients. For anionic compounds, attenuation was the highest in the two rivers with the lowest discharge, while the pattern was not as clear for neutral or cationic compounds. For most compounds the results obtained from active sampling were not significantly different from those using POCIS, demonstrating that the cost and labor efficient POCIS is suitable to determine the attenuation of organic micropollutants in rivers.

  • 17.
    Li, Zhe
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Radke, Michael
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Flume experiments to investigate the environmental fate of pharmaceuticals and their transformation products in streams2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 10, p. 6009-6017Article in journal (Refereed)
    Abstract [en]

    The hyporheic zone—the transition region beneath and alongside the stream bed—is a central compartment for attenuation of organic micropollutants in rivers. It provides abundant sorption sites and excellent conditions for biotransformation. We used a bench-scale flume to study the fate of 19 parent pharmaceuticals (PPs) and the formation of 11 characteristic transformation products (TPs) under boundary conditions similar to those in hyporheic zones. The persistence of PPs ranged from readily degradable with a dissipation half-life (DT50) as short as 1.8 days (acetaminophen, ibuprofen) to not degradable (chlorthalidone, fluconazole). The temporal and spatial patterns of PP and TP concentrations in pore water were heterogeneous, reflecting the complex hydraulic and biogeochemical conditions in hyporheic zones. Four TPs (carbamazepine-10,11-epoxide, metoprolol acid, 1-naphthol, and saluamine) were exclusively formed in the sediment compartment and released to surface water, highlighting their potential to be used as indicators for characterizing hyporheic transformation of micropollutants in streams. The accumulation of certain TPs over the experimental period illustrates that we might face a peak of secondary contamination by TPs far from the point of release of the original contaminants into a stream. Such TPs should be considered as priority candidates for a higher-tier environmental risk assessment.

  • 18.
    McLachlan, Michael S.
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Kierkegaard, Amelie
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Radke, Michael
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Malmvärn, Anna
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Alsberg, Tomas
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Arnot, Jon A.
    Brown, Trevor N.
    Wania, Frank
    Breivik, Knut
    Xu, Shihe
    Using Model-Based Screening to Help Discover Unknown Environmental Contaminants2014In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 48, no 13, p. 7264-7271Article in journal (Refereed)
    Abstract [en]

    Of the tens of thousands of chemicals in use, only a small fraction have been analyzed in environmental samples. To effectively identify environmental contaminants, methods to prioritize chemicals for analytical method development are required. We used a high-throughput model of chemical emissions, fate, and bioaccumulation to identify chemicals likely to have high concentrations in specific environmental media, and we prioritized these for target analysis. This model-based screening was applied to 215 organosilicon chemicals culled from industrial chemical production statistics. The model-based screening prioritized several recognized organosilicon contaminants and generated hypotheses leading to the selection of three chemicals that have not previously been identified as potential environmental contaminants for target analysis. Trace analytical methods were developed, and the chemicals were analyzed in air, sewage sludge, and sediment. All three substances were found to be environmental contaminants. Phenyl-tris(trimethylsiloxy)silane was present in all samples analyzed, with concentrations of similar to 50 pg m(-3) in Stockholm air and similar to 0.5 ng g(-1) dw in sediment from the Stockholm archipelago. Tris(trifluoropropyl)trimethyl-cyclotrisiloxane and tetrakis(trifluoropropyl)tetramethyl-cyclotetrasiloxane were found in sediments from Lake Mjosa at similar to 1 ng g(-1) dw. The discovery of three novel environmental contaminants shows that models can be useful for prioritizing chemicals for exploratory assessment.

  • 19.
    Mustajärvi, Lukas
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Eek, Espen
    Cornelissen, Gerard
    Eriksson-Wiklund, Ann-Kristin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Undeman, Emma
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    In situ benthic flow-through chambers to determine sediment-to-water fluxes of legacy hydrophobic organic contaminants2017In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 231, p. 854-862Article in journal (Refereed)
    Abstract [en]

    Contaminated sediment can release hydrophobic organic contaminants (HOCs) and thereby act as a secondary source of primarily legacy hazardous substances to the water column. There is therefore a need for assessments of the release of HOCs from contaminated sediment for prioritization of management actions. In situ assessment of HOC sediment-to-water flux is currently done with (closed) benthic flux chambers, which have a sampling time exceeding one month. During this time, the water inside the chamber is depleted of oxygen and the effect of bioturbation on the sediment-to-water release of HOCs is largely ignored. Here we present a novel benthic flux chamber, which measures sediment-to-water flux of legacy HOCs within days, and includes the effect of bioturbation since ambient oxygen levels inside the chamber are maintained by continuous pumping of water through the chamber. This chamber design allows for sediment-to-water flux measurements under more natural conditions. The chamber design was tested in a contaminated Baltic Sea bay. Measured fluxes were 62–2300 ng m−2 d−1 for individual polycyclic aromatic hydrocarbons (PAHs), and 5.5–150 ng m−2 d−1 for polychlorinated biphenyls (PCBs). These fluxes were 3–23 times (PAHs) and 12–74 times (PCBs) higher than fluxes measured with closed benthic chambers deployed in parallel at the same location. We hypothesize that the observed difference in HOC flux between the two chamber designs are partly an effect of bioturbation. This hypothesized effect of bioturbation was in accordance with literature data from experimental studies.

  • 20.
    Mustajärvi, Lukas
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Eriksson-Wiklund, Ann-Kristin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Jahnke, Annika
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Transferring mixtures of chemicals from sediment to a bioassay using silicone-based passive sampling and dosing2017In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 19, no 11, p. 1404-1413Article in journal (Refereed)
    Abstract [en]

    Environmental mixtures of chemicals consist of a countless number of compounds with unknown identity and quantity. Yet, chemical regulation is mainly built around the assessment of single chemicals. Existing frameworks for assessing the toxicity of mixtures require that both the chemical composition and quantity are known. Quantitative analyses of the chemical composition of environmental mixtures are however extremely challenging and resource-demanding. Bioassays may therefore serve as a useful approach for investigating the combined toxicity of environmental mixtures of chemicals in a cost-efficient and holistic manner. In this study, an unknown environmental mixture of bioavailable semi-hydrophobic to hydrophobic chemicals was sampled from a contaminated sediment in a coastal Baltic Sea area using silicone polydimethylsiloxane (PDMS) as an equilibrium passive sampler. The chemical mixture was transferred to a PDMS-based passive dosing system, and its applicability was demonstrated using green algae Tetraselmis suecica in a cell viability assay. The proportion of dead cells increased significantly with increasing exposure level and in a dose–response manner. At an ambient concentration, the proportion of dead cells in the population was nearly doubled compared to the control; however, the difference was non-significant due to high inter-replicate variability and a low number of replicates. The validation of the test system regarding equilibrium sampling, loading efficiency into the passive dosing polymer, stability of the mixture composition, and low algal mortality in control treatments demonstrates that combining equilibrium passive sampling and passive dosing is a promising tool for investigating the toxicity of bioavailable semi-hydrophobic and hydrophobic chemicals in complex environmental mixtures.

  • 21.
    Mustajärvi, Lukas
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Nybom, Inna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Eriksson-Wiklund, Ann-Kristin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Eek, Espen
    Cornelissen, Gerard
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    How Important is Bioturbation for Sediment-to-Water Flux of Polycyclic Aromatic Hydrocarbons in the Baltic Sea?2019In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 38, no 8, p. 1803-1810Article in journal (Refereed)
    Abstract [en]

    In the present study a recently developed benthic flow-through chamber was used to assess the sediment-to-water flux of polycyclic aromatic hydrocarbons (PAHs) at 4 sites on the Swedish Baltic Sea coast. The flow-through chamber allows for assessment of the potential effect of bioturbation on the sediment-to-water flux of hydrophobic organic contaminants. The sediments at the 4 investigated sites have both varying contamination degree and densities of bioturbating organisms. The flux of individual PAHs measured with the flow-through chamber ranged between 21 and 510, 11 and 370, 3 and 9700, and 62 and 2300 ng m(-2) d(-1) for the 4 sites. To assess the potential effect of bioturbation on the sediment-to-water flux, 3 flow-through and closed chambers were deployed in parallel at each site. The activity of benthic organisms is attenuated or halted because of depletion of oxygen in closed benthic chambers. Therefore, the discrepancy in flux measured with the 2 different chamber designs was used as an indication of a possible effect of bioturbation. A potential effect of bioturbation on the sediment-to-water flux by a factor of 3 to 55 was observed at sites with a high density of bioturbating organisms (e.g., Marenzelleria spp., Monoporeia affinis, and Macoma balthica of approximately 860-1200 individuals m(-2)) but not at the site with much lower organism density (<200 individuals m(-2)). One site had a high organism density and a low potential effect of bioturbation, which we hypothesize to be caused by the dominance of oligochaetes/polychaetes at this site because worms (Marenzelleria spp.) reach deeper into the sediment than native crustaceans and mollusks.

  • 22.
    Mustajärvi, Lukas
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Nybom, Inna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Eriksson-Wiklund, Ann-Kristin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Eek, Espen
    Cornelissen, Gerard
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    What the flux? – Field assessment of sediment-to-water fluxes of PAHs on the Swedish Baltic Sea coast and the impact of bioturbationManuscript (preprint) (Other academic)
  • 23.
    Quadra, Gabrielle R.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Universidade Federal de Juiz de Fora, Brazil.
    Lino, Adan
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Malm, Olaf
    Barros, Nathan
    Guida, Yago
    Thomaz, Jose
    Mendonca, Raquel
    Cardoso, Simone
    Estrada, Carlos
    Rust, Felipe
    Roland, Fabio
    Environmental Risk of Metal Contamination in Sediments of Tropical Reservoirs2019In: Bulletin of Environmental Contamination and Toxicology, ISSN 0007-4861, E-ISSN 1432-0800, Vol. 103, no 2, p. 292-301Article in journal (Refereed)
    Abstract [en]

    Reservoir sediment can work as both sink and source for contaminants. Once released into the water column, contaminants can be toxic to biota and humans. We investigate potential ecological risk to benthic organisms by metals contamination in six reservoirs in Southeast Brazil. Results of the bioavailable fraction of copper (Cu), chromium (Cr), cadmium (Cd), lead (Pb), zinc (Zn), and iron (Fe) in sediment samples are presented. Considering Cu, Cd, and Zn concentrations, about 6% of the samples exceeded the threshold effect levels of sediment quality guidelines. The comparison to sediment quality guidelines is conservative because we used a moderate metal extraction. Control of contaminant sources in these reservoirs is key because they are sources of water and food. The mixture toxicity assessment showed an increased incidence of toxicity to aquatic organisms showing that mixture toxicity should be taken into account in sediment assessment criteria.

  • 24.
    Reppas-Chrysovitsinos, Efstathios
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    MacLeod, Matt
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Screening-level exposure-based prioritization to identify potential POPs, vPvBs and planetary boundary threats among Arctic contaminants2017In: Emerging Contaminants, ISSN 2405-6650, E-ISSN 2405-6642, Vol. 3, no 2, p. 85-94Article in journal (Refereed)
    Abstract [en]

    A report that reviews Arctic contaminants that are not currently regulated as persistent organic pollutants (POPs) under international treaties was recently published by the Arctic Monitoring and Assessment Programme (AMAP). We evaluated 464 individual chemicals mentioned in the AMAP report according to hazard profiles for POPs, very persistent and very bioaccumulative (vPvB) chemicals, and two novel and distinct hazard profiles we derived from the planetary boundary threat framework. The two planetary boundary threat profiles assign high priority to chemicals that will be mobile and poorly reversible environmental contaminants. Utilizing persistence as a proxy for poor reversibility, we defined two exposure-based hazard profiles; airborne persistent contaminants (APCs) and waterborne persistent contaminants (WPCs) that are potential planetary boundary threats. We used in silico estimates of physicochemical properties and multimedia models to calculate hazard metrics for persistence, bioaccumulation and long-range transport potential, then we synthesized this information into four exposure-based hazard scores of the potential of each AMAP chemical to fit each of the POP, vPvB, APC and WPC exposure-based hazard profiles. As an alternative to adopting a “bright line” score that represented cause for concern, we scored the AMAP chemicals by benchmarking against a reference set of 148 known and relatively well-studied contaminants and expressed their exposure-based hazard scores as percentile ranks against the scores of the reference set chemicals. Our results show that scores in the four exposure-based hazard profiles provide complementary information about the potential environmental exposure-based hazards of the AMAP chemicals. Our POP, vPvB, APC and WPC exposure-based hazard scores identify high priority chemicals for further study from among the AMAP contaminants.

  • 25.
    Reppas-Chrysovitsinos, Efstathios
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    MacLeod, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Exploring the Chemical Space Occupied by Non-ionizing Organic Chemicals with Hazardous Environmental Exposure PotentialManuscript (preprint) (Other academic)
  • 26.
    Reppas-Chrysovitsinos, Efstathios
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    MacLeod, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    In Silico Screening-Level Prioritization of 8468 Chemicals Produced in OECD Countries to Identify Potential Planetary Boundary Threats2018In: Bulletin of Environmental Contamination and Toxicology, ISSN 0007-4861, E-ISSN 1432-0800, Vol. 100, no 1, p. 134-146Article in journal (Refereed)
    Abstract [en]

    Legislation such as the Stockholm Convention and REACH aim to identify and regulate the production and use of chemicals that qualify as persistent organic pollutants (POPs) and very persistent and very bioaccumulative (vPvB) chemicals, respectively. Recently, a series of studies on planetary boundary threats proposed seven chemical hazard profiles that are distinct from the POP and vPvB profiles. We previously defined two exposure-based hazard profiles; airborne persistent contaminants (APCs) and waterborne persistent contaminants (WPCs) that correspond to two profiles of chemicals that are planetary boundary threats. Here, we extend our method to screen a database of chemicals consisting of 8648 substances produced within the OECD countries. We propose a new scoring scheme to disentangle the POP, vPvB, APC and WPC profiles by focusing on the spatial range of exposure potential, discuss the relationship between high exposure hazard and elemental composition of chemicals, and identify chemicals with high exposure hazard potential.

  • 27.
    Reppas-Chrysovitsinos, Efstathios
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    MacLeod, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    In silico Screening-Level Prioritization of 8648 Chemicals Produced in OECD Countries to Identify Potential Planetary Boundary ThreatsManuscript (preprint) (Other academic)
  • 28.
    Reppas-Chrysovitsinos, Efstathios
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    MacLeod, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Screening-level models to estimate partition ratios of organic chemicals between polymeric materials, air and water2016In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 18, no 6, p. 667-676Article in journal (Refereed)
    Abstract [en]

    Polymeric materials flowing through the technosphere are repositories of organic chemicals throughout their life cycle. Equilibrium partition ratios of organic chemicals between these materials and air (KMA) or water (KMW) are required for models of fate and transport, high-throughput exposure assessment and passive sampling. KMA and KMW have been measured for a growing number of chemical/ material combinations, but significant data gaps still exist. We assembled a database of 363 KMA and 910 KMW measurements for 446 individual compounds and nearly 40 individual polymers and biopolymers, collected from 29 studies. We used the EPI Suite and ABSOLV software packages to estimate physicochemical properties of the compounds and we employed an empirical correlation based on Trouton's rule to adjust the measured KMA and KMW values to a standard reference temperature of 298 K. Then, we used a thermodynamic triangle with Henry's law constant to calculate a complete set of 1273 KMA and KMW values. Using simple linear regression, we developed a suite of single parameter linear free energy relationship (spLFER) models to estimate KMA from the EPI Suite-estimated octanol-air partition ratio (KOA) and KMW from the EPI Suite-estimated octanol-water (KOW) partition ratio. Similarly, using multiple linear regression, we developed a set of polyparameter linear free energy relationship (ppLFER) models to estimate KMA and KMW from ABSOLV-estimated Abraham solvation parameters. We explored the two LFER approaches to investigate (1) their performance in estimating partition ratios, and (2) uncertainties associated with treating all different polymers as a single bulk polymeric material compartment. The models we have developed are suitable for screening assessments of the tendency for organic chemicals to be emitted from materials, and for use in multimedia models of the fate of organic chemicals in the indoor environment. In screening applications we recommend that K-MA and K-MW be modeled as 0.06 x K-OA and 0.06 x K-OW respectively, with an uncertainty range of a factor of 15.

  • 29.
    Ribbenstedt, Anton
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mustajärvi, Lukas
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mayer, Philipp
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Passive dosing of triclosan in multigeneration tests with copepods – stable exposure concentrations and effects at the low μg/L range2017In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 36, no 5, p. 1254-1260Article in journal (Refereed)
    Abstract [en]

    Ecotoxicity testing is a crucial component of chemical risk assessment. Still, due to methodological difficulties related to controlling exposure concentrations over time, data on long-term effects of organic chemicals at low concentrations are limited. The aim of the present study was, therefore, to test the applicability of passive dosing to maintain stable concentrations of the organochlorine bacteriocide triclosan in the water phase during a 6-wk multigeneration population development test with the harpacticoid copepod Nitocra spinipes. Triclosan was loaded into silicone (1000 mg), which was used as passive dosing phase in the exposure vials. The distribution ratio for triclosan between silicone and water (Dsilicone-water) was 10466 +/- 1927. A population development test was conducted at 3 concentration levels of triclosan that were measured to be 3 mu g/L to 5 mu g/L, 7 mu g/L to 11 mu g/L and 16 mu g/L to 26 mu g/L. The results demonstrate that passive dosing is applicable for long-term ecotoxicity testing of organic chemicals, including during significant growth of the test organism population. Shifts in the demographic structure of the population during exposure suggest the most severe effects were exerted on juvenile development. Progressively lower development index values in the populations exposed to increasing triclosan concentrations suggest developmental retardation. The results further stress the need for chronic exposure during ecotoxicity testing in chemical risk assessment because even the most sensitive endpoint was not significant until after 7 d of exposure.

  • 30.
    Salvado, Joan A.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Carrizo, Daniel
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Observation-Based Assessment of PBDE Loads in Arctic Ocean Waters2016In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 50, no 5, p. 2236-2245Article in journal (Refereed)
    Abstract [en]

    Little is known about the distribution of polybrominated diphenyl ethers (PBDE)-also known as flame retardants- in major ocean compartments, with no reports yet for the large deep-water masses of the Arctic Ocean. Here, PBDE concentrations, congener patterns and inventories are presented for the different water masses of the pan-Arctic shelf seas and the interior basin. Seawater samples were collected onboard three cross-basin oceanographic campaigns in 2001, 2005, and 2008 following strict trace-clean protocols. Sigma 14PBDE concentrations in the Polar Mixed Layer (PML; a surface water mass) range from 0.3 to 11.2 pg.L-1, with higher concentrations in the pan-Arctic shelf seas and lower levels in the interior basin. BDE-209 is the dominant congener in most of the pan-Arctic areas except for the ones close to North America, where pentaBDE and tetra-BDE congeners predominate. In deep-water masses, Sigma 14PBDE concentrations are up to 1 order of magnitude higher than in the PML. Whereas BDE-209 decreases with depth, the less-brominated congeners, particularly BDE-47 and BDE-99, increase down through the water column. Likewise, concentrations of BDE-71 -a congener not present in any PBDE commercial mixture increase with depth, which potentially is the result of debromination of BDE-209. The inventories in the three water masses of the Central Arctic Basin (PML, intermediate Atlantic Water Layer, and the Arctic Deep Water Layer) are 158 +/- 77 kg, 6320 +/- 235 kg and 30800 +/- 3100 kg, respectively. The total load of PBDEs in the entire Arctic Ocean shows that only a minor fraction of PBDEs emissions are transported to the Arctic Ocean. These findings represent the first PBDE data in the deep-water compartments of an ocean.

  • 31.
    Sobek, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Arp, Hans Peter H.
    Wiberg, Karin
    Hedman, Jenny
    Cornelissen, Gerard
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Aerosol-Water Distribution of PCDD/Fs and PCBs in the Baltic Sea Region2013In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 47, no 2, p. 781-789Article in journal (Refereed)
    Abstract [en]

    Atmospheric deposition is a major pathway of PCDD/Fs to the Baltic Sea. We studied the aerosol-water distribution for aerosols collected close to the Baltic Sea in order to investigate the availability of pollutants sorbed to aerosols deposited on water. Aerosols were analyzed for both total concentration (Soxhlet extraction) and the freely dissolved water concentration (extraction with 17-mu m polyoxymethylene equilibrium passive samplers). Concentrations of PCDD/F and sum PCB-7 in aerosols were 65-1300 pg/g dw TEQ and 22-100 ng/g dw, respectively. Organic carbon (OC)-normalized aerosol water distribution ratios (K-aer-water,K-OC) were consistently lower (factor 2-60) than previously determined sediment organic carbon water distribution ratios (K-sed,K-OC). Hence PCDD/Fs and PCBs entering the Baltic Sea through aerosol deposition seem to be more available for desorption to the water phase than PCDD/Fs and PCBs sorbed to sediment. Further, we investigated whether aerosol water distribution may be predicted from the air aerosol partitioning constant multiplied by the Henry's Law constant. This proposed model for aerosol water distribution underestimated measured values for PCBs by factors of 1-17 and for PCDD/Fs by more than a factor 10. These findings can be used to improve future fate modeling of PCBs and PCDD/Fs in marine environments and specifically the Baltic Sea.

  • 32.
    Sobek, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bejgarn, Sofia
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Rudén, Christina
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    The dilemma in prioritizing chemicals for environmental analysis: known versus unknown hazards2016In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 18, no 8, p. 1042-1049Article in journal (Refereed)
    Abstract [en]

    A major challenge for society is to manage the risks posed by the many chemicals continuously emitted to the environment. All chemicals in production and use cannot be monitored and science-based strategies for prioritization are essential. In this study we review available data to investigate which substances are included in environmental monitoring programs and published research studies reporting analyses of chemicals in Baltic Sea fish between 2000 and 2012. Our aim is to contribute to the discussion of priority settings in environmental chemical monitoring and research, which is closely linked to chemical management. In total, 105 different substances or substance groups were analyzed in Baltic Sea fish. Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were the most studied substances or substance groups. The majority, 87%, of all analyses comprised 20% of the substances or substance groups, whereas 46 substance groups (44%) were analyzed only once. Almost three quarters of all analyses regarded a POP-substance (persistent organic pollutant). These results demonstrate that the majority of analyses on environmental contaminants in Baltic Sea fish concern a small number of already regulated chemicals. Legacy pollutants such as POPs pose a high risk to the Baltic Sea due to their hazardous properties. Yet, there may be a risk that prioritizations for chemical analyses are biased based on the knowns of the past. Such biases may lead to society failing in identifying risks posed by yet unknown hazardous chemicals. Alternative and complementary ways to identify priority chemicals are needed. More transparent communication between risk assessments performed as part of the risk assessment process within REACH and monitoring programs, and information on chemicals contained in consumer articles, would offer ways to identify chemicals for environmental analysis.

  • 33.
    Sobek, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Bejgarn, Sofia
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Rudén, Christina
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Molander, Linda
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    In the shadow of the Cosmetic Directive - Inconsistencies in EU environmental hazard classification requirements for UV-filters2013In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 461, p. 706-711Article in journal (Refereed)
    Abstract [en]

    UV-filters are chemicals with potentially environmental hazardous properties. In the European Union (EU), UV-filters contained in sunscreen products are currently regulated by the Cosmetic Directive (from July 2013 by the Cosmetic Products Regulation). Environmental hazard classifications according to the regulation on classification, labelling and packaging of substances and mixtures (CLP) must be determined for UV-filters contained in industrial chemical products, whereas UV-filters contained in sunscreens are exempted from CLP. In this study we determined the potential environmental hazard classifications of UV-filters and sunscreen products if the CLP regulation was to be required for cosmetic products. Two sunscreen products were evaluated in accordance with the aquatic environmental hazard criteria for mixtures. The results highlight that the inconsistencies in the current EU regulation of UV filters hamper the risk management of environmental hazards of UV filters used in cosmetic products. Almost 50% of the investigated UV-filters approved for use in cosmetic products on the European market according to the current Cosmetic Directive were identified to meet the CLP classification as being hazardous to the aquatic environment. Assuming a worst-case scenario, the two examined sunscreens could both be classified as hazardous to the aquatic environment with long-lasting effects according to CLP classification criteria. Hence, if the CLP regulation was applicable to sunscreen products, both brands could potentially be labelled with the environmental hazard pictogram and associated hazard and precautionary statements. Including cosmetic products, and thereby sunscreens, in the CLP regulation would contribute to a more harmonized and transparent regulation of potentially hazardous substances on the EU market.

  • 34.
    Sobek, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Deep Water Masses and Sediments Are Main Compartments for Polychlorinated Biphenyls in the Arctic Ocean2014In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 48, no 12, p. 6719-6725Article in journal (Refereed)
    Abstract [en]

    There is a wealth of studies of polychlorinated biphenyls (PCB) in surface water and biota of the Arctic Ocean. Still, there are no observation-based assessments of PCB distribution and inventories in and between the major Arctic Ocean compartments. Here, the first water column distribution of PCBs in the central Arctic Ocean basins (Nansen, Amundsen, and Makarov) is presented, demonstrating nutrient-like vertical profiles with 5-10 times higher concentrations in the intermediate and deep water masses than in surface waters. The consistent vertical profiles in all three Arctic Ocean basins likely reflect buildup of PCBs transported from the shelf seas and from dissolution and/or mineralization of settling particles. Combined with measurement data on PCBs in other Arctic Ocean compartments collected over the past decade, the total Arctic Ocean inventory of Sigma 7PCB was estimated to 182 +/- 40 t (+/- 1 standard error of the mean), with sediments (144 +/- 40 t), intermediate (5 +/- 1 t) and deep water masses (30 +/- 2 t) storing 98% of the PCBs in the Arctic Ocean. Further, we used hydrographic and carbon cycle parametrizations to assess the main pathways of PCBs into and out of the Arctic Ocean during the 20th century. River discharge appeared to be the major pathway for PCBs into the Arctic Ocean with 115 +/- 11 t, followed by ocean currents (52 +/- 17 t) and net atmospheric deposition (30 +/- 28 t). Ocean currents provided the only important pathway out of the Arctic Ocean, with an estimated cumulative flux of 22 +/- 10 t. The observation-based inventory of Sigma 7PCB of 182 +/- 40 t is consistent with the contemporary inventory based on cumulative fluxes for Sigma 7PCB of 173 +/- 36 t. Information on the concentration and distribution of PCBs in the deeper compartments of the Arctic Ocean improves our understanding of the large-scale fate of POPs in the Arctic and may also provide a means to test and improve models used to assess the fate of organic pollutants in the Arctic.

  • 35.
    Sobek, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sundqvist, Kristina L.
    Assefa, Anteneh T.
    Wiberg, Karin
    Baltic Sea sediment records: Unlikely near-future declines in PCBs and HCB2015In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 518, p. 8-15Article in journal (Refereed)
    Abstract [en]

    We present a comprehensive study on PCBs and HCB in dated sediment cores from the Baltic Sea covering the 20th century, and compare their spatiotemporal trends with those of PCDD/Fs from the same areas. PCB concentrations in coastal impacted sediment followed the temporal trend of estimated global emissions of PCBs and thus responded quickly to changes in global industrial use, whereas concentrations in offshore sediment needed 10-20 years longer to respond. Differences in spatiotemporal trends of PCDD/Fs and PCBs were smaller than expected based on documented differences in key sources and source areas. Sediment concentrations of HCB varied little over time and space, but concentrations are increasing in recent years. The steep PCB concentration reduction over time observed for the late 20th century levelled off during the last 20 years, and levels of PCBs appear to be at or near a steady-state condition. Capsule: PCB concentrations in Baltic Sea sediments appear to be at or near steady-state, and no significant concentration decreases are to be expected in the near future.

  • 36.
    Sobek, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Wiberg, K.
    Sundqvist, K. L.
    Haglund, P.
    Jonsson, Per
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Cornelissen, Gerard
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM). Norwegian Geotechnical Institute, Norway; Norwegian University of Life Sciences, Norway.
    Coastal sediments in the Gulf of Bothnia as a source of dissolved PCDD/Fs and PCBs to water and fish2014In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 487, p. 463-470Article in journal (Refereed)
    Abstract [en]

    High levels of PCDD/Fs and PCBs in Baltic Sea biota have been a matter of great concern during the last decades. We measured the freely dissolved concentrations of PCDD/Fs and PCBs in sediment pore water and bottom water in eight areas along the Swedish coast of the Gulf of Bothnia, by using state-of-the-art passive samplers. Chemical activity ratios (calculated from freely dissolved concentrations in pore water and bottom water based on chemical activity ratios) for PCDD/Fs were higher than 1 at all stations (PCDD/Fs average 27; stdev 22). High activity ratios suggest that the sediments have a potential to act as a source of dissolved PCDD/Fs to the water column. Activity ratios for PCBs varied between 0.3 and 17 (average 2; stdev 4). The concentrations of PCDD/Fs and PCBs in bottom water were significantly correlated with concentrations in sediment pore water (p < 0.00001 to p = 0.03) as well as with concentrations in juvenile perch caught in the same areas (p < 0.00001 to p = 0.02). To our knowledge, this is the first study demonstrating a correlation between in-situ measured freely dissolved PCDD/F concentrations and lipid-normalized contents in stationary fish. Our results confirm that freely dissolved concentrations should be used as chemical predictors of bioaccumulation. The results from this study imply that continued efforts to reduce levels of PCDD/Fs and PCBs in coastal sediments will have positive effects on concentrations of these contaminants in lower trophic levels of Baltic Sea ecosystems.

  • 37.
    Yuan, Bo
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Brüchert, Volker
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    de Witt, Cynthia A.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Temporal Trends of C-8-C-36 Chlorinated Paraffins in Swedish Coastal Sediment Cores over the Past 80 Years2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 24, p. 14199-14208Article in journal (Refereed)
    Abstract [en]

    Temporal trends of chlorinated paraffins (CPs) were analyzed in three sediment cores collected near different potential CP sources along the Swedish Baltic Sea coast. C-8-C-36 CPs were found in sediment dating back to the 1930s. The maximum CP concentrations found in proximity to a metropolitan sewage treatment plant, a wood related industrial area, and a steel factory were 48; 160, and 1400 ng/g d.w., respectively, in sediment sections dated from the early 1990s or the 2000s. The temporal trends agree with statistics on CP importation in Sweden or local industrial activities. MCCPs (C-14-C-17 CPs) and LCCPs (C->= 18 CPs) predominated, in most sediments with average percentage compositions of 47 +/- 20% and 37 +/- 20%, respectively. Concentrations of SCCPs in the three cores showed a decreasing trend in recent years. The temporal trends of MCCPs indicated that these are currently the predominant CPs in use. This study showed for the first time that LCCPs from C-18 to C-36, as well as C-8-C-17 CPs, are persistent in sediments over the last 30-80 years, indicating that CPs are persistent chemicals regaidless of alkane-chain lengths.

  • 38.
    Ågerstrand, Marlene
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lilja, Karl
    Linderoth, Maria
    Wendt-Rasch, Lina
    Wernersson, Ann-Sofie
    Rudén, Christina
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    An academic researcher's guide to increased impact on regulatory assessment of chemicals2017In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 19, no 5, p. 644-655Article in journal (Refereed)
    Abstract [en]

    The interactions between academic research and regulatory assessment of chemicals may in theory seem straightforward: researchers perform studies, and these studies are used by regulators for decision-making. However, in practice the situation is more complex, and many factors decide a research study's regulatory use. According to several EU chemical legislations, all available and relevant studies can be used in hazard and risk assessment of chemicals. However, in practice, standard tests conducted under GLP and sponsored and provided by industry are predominantly used. Peer-reviewed studies from independent sources are often disregarded or disputed since they often do not comply with regulatory data requirements and quality criteria. To help bridge such a gap, the aim of this paper is to give an overview of the general workings of legislation of chemicals and propose a set of actions to increase the usability of research data. In the end, this may increase the use of academic research for decision-making and ultimately result in more science-based policies. From a policy perspective, useful scientific evidence comprises those studies that are sufficiently reliable and relevant. This is not in contradiction to the aims of research and generally accepted scientific standards.

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