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1.
  • Ahrens, Lutz (author)
  • Themed issues on per- and polyfluoroalkyl substances
  • 2019
  • In: Environmental Science: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 21, s. 1797-1802
  • Journal article (other academic/artistic)abstract
    • Guest editors Lutz Ahrens, Jonathan Benskin, Ian Cousins, Michelle Crimi and Christopher Higgins introduce the “Per- and polyfluoroalkyl substances (PFASs)” themed issue.
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2.
  • Anteneh, Assefa, et al. (author)
  • Tracing the sources of PCDD/Fs in Baltic Sea air by using metals as source markers
  • 2018
  • In: Environmental Science: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 20, s. 544-552
  • Journal article (peer-reviewed)abstract
    • The atmosphere is the major contributor of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Baltic Sea environment. In this study, we investigated the potential of using metals along with PCDD/Fs as markers of important emission sources of PCDD/Fs in air. The air concentrations of PCDD/F congeners (n = 17), other persistent organic pollutants (n = 8) and metals (n = 16) were determined in summer and winter air using high volume samplers at a rural field station (Aspvreten, Sweden) located close to the Baltic Sea coast. During winter, PCDD/F levels were on average 20 times higher than in summer (5.1 +/- 5.8 fg toxicity equivalents (TEQ) m(-3) and 0.26 +/- 0.18 fg TEQ m(-3), respectively) mostly due to a higher fraction of PCDFs. The increased levels of PCDD/Fs were pronounced mainly in air masses that had travelled from southern (S) and eastern (E) compass sectors. A principal component analysis (PCA) of metal levels in Scots pine (Pinus sylvestris) needles sampled to reflect various air emission source types helped to identify potential marker metals for selected known atmospheric emission sources of PCDD/Fs and to rank among the candidate source types. Brown coal burning, domestic burning and heavy oil burning appeared to be the source types that contribute most of the PCDD/Fs in Baltic Sea air. The current study demonstrates a successful approach for source tracing of PCDD/Fs in air, where integrated indices from seasonal and spatial patterns of PCDD/Fs as well as metal source markers were used to trace and rank sources.
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3.
  • Assefa, Anteneh, et al. (author)
  • Tracing the sources of PCDD/Fs in Baltic Sea air by using metals as source markers
  • 2018
  • In: Environmental Science. - Cambridge : Royal Society of Chemistry. - 2050-7887 .- 2050-7895. ; 20:3, s. 544-552
  • Journal article (peer-reviewed)abstract
    • The atmosphere is the major contributor of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Baltic Sea environment. In this study, we investigated the potential of using metals along with PCDD/Fs as markers of important emission sources of PCDD/Fs in air. The air concentrations of PCDD/F congeners (n = 17), other persistent organic pollutants (n = 8) and metals (n = 16) were determined in summer and winter air using high volume samplers at a rural field station (Aspvreten, Sweden) located close to the Baltic Sea coast. During winter, PCDD/F levels were on average 20 times higher than in summer (5.1 +/- 5.8 fg toxicity equivalents (TEQ) m-3 and 0.26 +/- 0.18 fg TEQ m-3, respectively) mostly due to a higher fraction of PCDFs. The increased levels of PCDD/Fs were pronounced mainly in air masses that had travelled from southern (S) and eastern (E) compass sectors. A principal component analysis (PCA) of metal levels in Scots pine (Pinus sylvestris) needles sampled to reflect various air emission source types helped to identify potential marker metals for selected known atmospheric emission sources of PCDD/Fs and to rank among the candidate source types. Brown coal burning, domestic burning and heavy oil burning appeared to be the source types that contribute most of the PCDD/Fs in Baltic Sea air. The current study demonstrates a successful approach for source tracing of PCDD/Fs in air, where integrated indices from seasonal and spatial patterns of PCDD/Fs as well as metal source markers were used to trace and rank sources.
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4.
  • Awad, Raed, et al. (author)
  • Emerging per- and polyfluoroalkyl substances (PFAS) in human milk from Sweden and China
  • 2020
  • In: Environmental Science. - : Royal Society of Chemistry. - 2050-7887 .- 2050-7895. ; 22:10, s. 2023-2030
  • Journal article (peer-reviewed)abstract
    • Twenty per- and polyfluoroalkyl substances (PFAS) were determined in human milk from residents of three Chinese cities (Shanghai, Jiaxing, and Shaoxing; [n = 10 individuals per city]), sampled between 2010 and 2016. These data were compared to a combination of new and previously reported PFAS concentrations in human milk from Stockholm, Sweden, collected in 2016 (n = 10 individuals). Across the three Chinese cities, perfluorooctanoate (PFOA; sum isomers), 9-chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS; also known as 6:2 Cl-PFESA or by its trade name "F53-B"), and perfluorooctane sulfonate (PFOS; sum isomers) occurred at the highest concentrations among all PFAS (up to 411, 976, and 321 pg mL-1, respectively), while in Stockholm, PFOA and PFOS were dominant (up to 89 and 72 pg mL-1, respectively). 3H-Perfluoro-3-[(3-methoxy-propoxy)propanoic acid] (ADONA) was intermittently detected but at concentrations below the method quantification limit (i.e. <10 pg mL-1) in Chinese samples, and was non-detectable in Swedish milk. The extremely high concentrations of F53-B in Chinese milk suggest that human exposure assessments focused only on legacy substances may severely underestimate overall PFAS exposure in breastfeeding infants.
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5.
  • Awad, Raed, et al. (author)
  • Emerging Per- and Polyfluoroalkyl Substances (PFAS) in Human Milk from Sweden and China
  • 2020
  • In: Environmental Science. - 2050-7887 .- 2050-7895. ; 19:22
  • Journal article (peer-reviewed)abstract
    • Abstract Twenty per- and polyfluoroalkyl substances (PFAS) were determined in human milk from residents of three Chinese cities (Shanghai, Jiaxing, and Shaoxing), sampled between 2010 and 2016. These data were compared to a combination of new and previously reported PFAS concentrations in human milk from Stockholm, Sweden, collected in 2016. Across the three Chinese cities, perfluorooctanoate (PFOA; sum isomers), 9-chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS; trade name F53-B), and perfluorooctane sulfonate (PFOS; sum isomers) occurred at the highest concentrations among all PFAS (up to 411, 976, and 321 pg/mL, respectively), while in Stockholm, PFOA and PFOS were dominant (up to 89 and 72 pg/mL, respectively). 3H-perfluoro-3-[(3-methoxy-propoxy) propanoic acid (ADONA) was intermittently detected but at concentrations below the method quantification limit (i.e. <10 pg/mL) in Chinese samples, and was non-detectable in Swedish milk. The extremely high concentrations of F53-B in Chinese milk suggest that human exposure assessments focused only on legacy substances may severely underestimate overall PFAS exposure in breastfeeding infants.
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6.
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7.
  • Balk, Fabian G. P., et al. (author)
  • Children's exposure to perfluoroalkyl acids - a modelling approach
  • 2019
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 21:11, s. 1875-1886
  • Journal article (peer-reviewed)abstract
    • Adults are mainly exposed to per- and polyfluoroalkyl substances (PFASs) via ingestion of food, inhalation of air and ingestion of dust, whereas for children the exposure to PFASs is largely unknown. This study aimed to reconstruct the serum concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS) in children after infancy up to 10.5 years of age and to test if dietary intake is the major exposure pathway for children to PFOA, PFOS and PFHxS after infancy. For this work, a dataset from a Finnish child cohort study was available, which comprised serum concentrations of the studied perfluoroalkyl acids (PFAAs) and PFAS concentration measurements in dust and air samples from the children's bedrooms. The calculated PFAA intakes were used in a pharmacokinetic model to reconstruct the PFAA serum concentrations from 1 to 10.5 years of age. The calculated PFOA and PFOS intakes were close to current regulatory intake thresholds and diet was the major exposure medium for the 10.5 year-olds. The one-compartment PK model reconstructed median PFOA and PFOS serum concentrations well compared to corresponding measured median serum concentrations, while the modelled PFHxS serum concentrations showed a constant underestimation. The results imply that children's exposure to PFOA and PFOS after breastfeeding and with increasing age resembles the exposure of adults. Further, the children in the Finnish cohort experienced a rather constant exposure to PFOA and PFOS between 1 and 10.5 years of age. The PFHxS exposure sources and respective pharmacokinetic parameter estimations need further investigation.
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8.
  • Baptista-Salazar, Carluvy, et al. (author)
  • Insights into the factors influencing mercury concentrations in tropical reservoir sediments
  • 2021
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 23:10, s. 1542-1553
  • Journal article (peer-reviewed)abstract
    • Thousands of dams are currently under construction or planned worldwide to meet the growing need for electricity. The creation of reservoirs could, however, lead to conditions that promote the accumulation of mercury (Hg) in surface sediments and the subsequent production of methylmercury (MeHg). Once produced, MeHg can bioaccumulate to harmful levels in organisms. It is unclear to what extent variations in physical features and biogeochemical factors of the reservoir impact Hg accumulation. The objective of this study was to identify key drivers of the accumulation of total Hg (THg) in tropical reservoir sediments. The concentration of THg in all analyzed depth intervals of 22 sediment cores from the five contrasting reservoirs investigated ranged from 16 to 310 ng g(-1) (n = 212, in the different sediment cores, the maximum depth varied from 18 to 96 cm). Our study suggests reservoir size to be an important parameter determining the concentration of THg accumulating in tropical reservoir sediments, with THg ranging up to 50 ng g(-1) in reservoirs with an area exceeding 400 km(2) and from 100 to 200 ng g(-1) in reservoirs with an area less than 80 km(2). In addition to the reservoir size, the role of land use, nutrient loading, biome and sediment properties (e.g., organic carbon content) was tested as potential drivers of THg levels. The principal component analysis conducted suggested THg to be related to the properties of the watershed (high degree of forest cover and low degree of agricultural land use), size and age of the reservoir, water residence time and the levels of nutrients in the reservoir. A direct correlation between THg and tested variables was, however, only observed with the area of the reservoir.
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9.
  • Bidleman, Terry F., et al. (author)
  • Bromoanisoles and Methoxylated Bromodiphenyl Ethers in Macroalgae from Nordic Coastal Regions
  • 2019
  • In: Environmental Science. - London : Royal Society of Chemistry. - 2050-7887 .- 2050-7895. ; , s. 881-892
  • Journal article (peer-reviewed)abstract
    • Marine macroalgae are used worldwide for human consumption, animal feed, cosmetics and agriculture. In addition to beneficial nutrients, macroalgae contain halogenated natural products (HNPs), some of which have toxic properties similar to those of well-known anthropogenic contaminants. Sixteen species of red, green and brown macroalgae were collected in 2017–2018 from coastal waters of the northern Baltic Sea, Sweden Atlantic and Norway Atlantic, and analyzed for bromoanisoles (BAs) and methoxylated bromodiphenyl ethers (MeO-BDEs). Target compounds were quantified by gas chromatography-low resolution mass spectrometry (GC-LRMS), with qualitative confirmation in selected species by GC-high resolution mass spectrometry (GC-HRMS). Quantified compounds were 2,4-diBA, 2,4,6-triBA, 2′-MeO-BDE68, 6-MeO-BDE47, and two tribromo-MeO-BDEs and one tetrabromo-MeO-BDE with unknown bromine substituent positions. Semiquantitative results for pentabromo-MeO-BDEs were also obtained for a few species by GC-HRMS. Three extraction methods were compared; soaking in methanol, soaking in methanol–dichloromethane, and blending with mixed solvents. Extraction yields of BAs did not differ significantly (p > 0.05) with the three methods and the two soaking methods gave equivalent yields of MeO-BDEs. Extraction efficiencies of MeO-BDEs were significantly lower using the blend method (p < 0.05). For reasons of simplicity and efficiency, the soaking methods are preferred. Concentrations varied by orders of magnitude among species: ∑2BAs 57 to 57 700 and ∑5MeO-BDEs < 10 to 476 pg g−1 wet weight (ww). Macroalgae standing out with ∑2BAs >1000 pg g−1 ww were Ascophyllum nodosum, Ceramium tenuicorne, Ceramium virgatum, Fucus radicans, Fucus serratus, Fucus vesiculosus, Saccharina latissima, Laminaria digitata, and Acrosiphonia/Spongomorpha sp. Species A. nodosum, C. tenuicorne, Chara virgata, F. radicans and F. vesiculosus (Sweden Atlantic only) had ∑5MeO-BDEs >100 pg g−1ww. Profiles of individual compounds showed distinct differences among species and locations.
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10.
  • Bighiu, Maria, et al. (author)
  • Interactions with freshwater biofilms cause rapid removal of common herbicides through degradation - evidence from microcosm studies
  • 2021
  • In: Environmental Science: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 23, s. 66-72
  • Journal article (peer-reviewed)abstract
    • We investigated the role of periphyton biofilms for the fate of three common herbicides, i.e. bentazone, metazachlor and metribuzin, at low, environmental levels and 100 times higher, during a 16 days laboratory experiment. We found that herbicide water concentrations were stable during the first 8 days, whereas substantial declines (>78%) occurred between days 8-16 for all three herbicides. These rapid declines were explained only to a small extent (<8% of the total herbicide loss) by biofilm sorption. As herbicide concentrations in light and dark treatments without biofilms were similar, and the applied light regimen did not cover the UV-spectrum, herbicide photolysis was ruled out as a possible explanation for the observed declines. Furthermore, based on the compounds' characteristics, also volatilization was judged negligible. Therefore, we conjecture that the observed declines in herbicides were due to biodegradation and subsequent evasion of (CO2)-C-14 that was driven by enzymatic action from heterotrophic microbes. We reason that heterotrophic microbes used herbicide molecules as labile organic C-sources during C-limitation. Future studies should identify the microbial communities and genes involved in biodegradation in order to understand better the role of biofilms for the self-purification of surface waters.
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11.
  • Binnington, Matthew J, et al. (author)
  • Effects of preparation on nutrient and environmental contaminant levels in Arctic beluga whale (Delphinapterus leucas) traditional foods
  • 2017
  • In: Environmental Science. - : Royal Society of Chemistry. - 2050-7887 .- 2050-7895. ; 19:8, s. 1000-1015
  • Journal article (peer-reviewed)abstract
    • For Canadian Arctic indigenous populations, marine mammal (MM) traditional foods (TFs) represent sources of both important nutrients and hazardous environmental contaminants. Food preparation is known to impact the nutrient and environmental contaminant content of processed items, yet the impacts of preparation on indigenous Arctic MM TFs remain poorly characterized. In order to determine how the various processes involved in preparing beluga blubber TFs affect their levels of nutrients and environmental contaminants, we collected blubber samples from 2 male beluga whales, aged 24 and 37 years, captured during the 2014 summer hunting season in Tuktoyaktuk, Northwest Territories, and processed them according to local TF preparation methods. We measured the levels of select nutrients [selenium (Se), polyunsaturated fatty acids (PUFAs)] and contaminants [organochlorine pesticides, perfluoroalkyl and polyfluoroalkyl substances (PFASs), polybrominated diphenyl ethers, polychlorinated biphenyls, polycyclic aromatic hydrocarbons (PAHs), mercury (Hg)] in raw and prepared (boiled, roasted, aged) beluga blubber TFs. The impacts of beluga blubber TF preparation methods on nutrient and environmental contaminant levels were inconsistent, as the majority of processes either did not appear to influence concentrations or affected the two belugas differently. However, roasting and ageing beluga blubber consistently impacted certain compounds: roasting blubber increased concentrations of hydrophilic substances (Se and certain PFASs) through solvent depletion and deposited PAHs from cookfire smoke. The solid-liquid phase separation involved in ageing blubber depleted hydrophilic elements (Se, Hg) and some ionogenic PFASs from the lipid-rich liquid oil phase, while PUFA levels appeared to increase, and hydrophobic persistent organic pollutants were retained. Ageing blubber adjacent to in-use smokehouses also resulted in considerable PAH deposition to processed samples. Our findings demonstrated that contaminant concentration differences were greater between the two sets of whale samples, based on age differences, than they were within each set of whale samples, due to variable preparation methods. When considering means to minimize human contaminant exposure while maximizing nutrient intake, consumption of aged liquid from younger male whales would be preferred, based on possible PUFA enhancement and selective depletion of hydrophilic environmental contaminants in this food item.
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12.
  • Bohlin, Pernilla, et al. (author)
  • Evaluation and guidelines for using polyurethane foam (PUF) passive air samplers in double-dome chambers to assess semi-volatile organic compounds (SVOCs) in non-industrial indoor environments
  • 2014
  • In: Environmental Science. - : Royal Society of Chemistry. - 2050-7887 .- 2050-7895. ; 16:11, s. 2617-2626
  • Journal article (peer-reviewed)abstract
    • Indoor air pollution has been recognized as an important risk factor for human health, especially in areas where people tend to spend most of their time indoors. Many semi-volatile organic compounds (SVOCs) have primarily indoor sources and are present in orders of magnitude higher concentrations indoors than outdoors. Despite this, awareness of SVOCs in indoor air and assessment of the link between indoor concentrations and human health have tagged behind those of outdoor air. This is partially related to challenges associated with indoor sampling of SVOCs. Passive air samplers (PASs), which are widely accepted in established outdoor air monitoring networks, have been used to fill the knowledge gaps on indoor SVOCs distribution. However, their applicability for indoor environments and the assessment of human health risks lack sufficient experimental data. To address this issue, we performed an indoor calibration study of polyurethane foam (PUF) PAS deployed in a double-dome chamber, covering both legacy and new SVOC classes. PUF-PAS and a continuous low-volume active air sampler (AAS) were co-deployed for a calibration period of twelve weeks. Based on the results from this evaluation, PUF-PAS in a double-bowl chamber is recommended for indoor sampling and health risk assessment of gas phase SVOCs, including novel brominated flame retardants (nBFR) providing sufficient exposure time is applied. Data for particle associated SVOCs suffered from significant uncertainties caused by low level of detection and low precision in this study. A more open chamber design for indoor studies may allow for higher sampling rates (R-s) and better performance for the particle associated SVOCs.
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13.
  • Bohlin, P., et al. (author)
  • Outdoor passive air monitoring of semi volatile organic compounds (SVOCs) : a critical evaluation of performance and limitations of polyurethane foam (PUF) disks
  • 2014
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 16:3, s. 433-444
  • Journal article (peer-reviewed)abstract
    • The most commonly used passive air sampler (PAS) (i.e. polyurethane foam (PUF) disk) is cheap, versatile, and capable of accumulating compounds present both in gas and particle phases. Its performance for particle associated compounds is however disputable. In this study, twelve sets of triplicate PUF-PAS were deployed outdoors for exposure periods of 1-12 weeks together with continuously operated active samplers, to characterize sampling efficiency and derive sampling rates (R-S) for compounds belonging to 7 SVOC classes (including particle associated compounds). PUF-PAS efficiently and consistently sampled polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), and eight novel brominated flame retardant (nBFR) compounds. Low accuracy and lack of sensitivity was observed for most polychlorinated dibenzo-p-dioxins/furans PCDD/Fs and polybrominated diphenyl ethers (PBDEs) (under the conditions of this study), with the exception of some congeners which may be used as qualitative markers for their respective classes. Application of compound specific R-S was found crucial for all compounds except PCBs. Sampling efficiency of the particle associated compounds was often low.
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14.
  • Bolinius, Dämien Johann, et al. (author)
  • A passive dosing method to determine fugacitycapacities and partitioning properties of leaves
  • 2016
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 18, s. 1325-1332
  • Journal article (peer-reviewed)abstract
    • The capacity of leaves to take up chemicals from the atmosphere and water in fl uences how contaminantsare transferred into food webs and soil. We provide a proof of concept of a passive dosing method tomeasure leaf/polydimethylsiloxane partition ratios ( K leaf/PDMS ) for intact leaves, using polychlorinatedbiphenyls (PCBs) as model chemicals. Rhododendron leaves held in contact with PCB-loaded PDMSreached between 76 and 99% of equilibrium within 4 days for PCBs 3, 4, 28, 52, 101, 118, 138 and 180.Equilibrium K leaf/PDMS extrapolated from the uptake kinetics measured over 4 days ranged from 0.075(PCB 180) to 0.371 (PCB 3). The K leaf/PDMS data can readily be converted to fugacity capacities of leaves( Z leaf ) and subsequently leaf/water or leaf/air partition ratios ( K leaf/water and K leaf/air ) using partitioning datafrom the literature. Results of our measurements are within the variability observed for plant/air partitionratios ( K plant/air ) found in the literature. Log K leaf/air from this study ranged from 5.00 (PCB 3) to 8.30(PCB 180) compared to log K plant/air of 3.31 (PCB 3) to 8.88 (PCB 180) found in the literature. The methodwe describe could provide data to characterize the variability in sorptive capacities of leaves that wouldimprove descriptions of uptake of chemicals by leaves in multimedia fate models.
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15.
  • Bolinius, Dämien J., et al. (author)
  • Evaluating the consumption of chemical products and articles as proxies for diffuse emissions to the environment
  • 2018
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 20:10, s. 1427-1440
  • Journal article (peer-reviewed)abstract
    • 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.
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16.
  • Breivik, Knut, et al. (author)
  • Introducing a nested multimedia fate and transport model for organic contaminants (NEM)
  • 2021
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; :8
  • Journal article (peer-reviewed)abstract
    • Some organic contaminants, including the persistent organic pollutants (POPs), have achieved global distribution through long range atmospheric transport (LRAT). Regulatory efforts, monitoring programs and modelling studies address the LRAT of POPs on national, continental (e.g. Europe) and/or global scales. Whereas national and continental-scale models require estimates of the input of globally dispersed chemicals from outside of the model domain, existing global-scale models either have relatively coarse spatial resolution or are so computationally demanding that it limits their usefulness. Here we introduce the Nested Exposure Model (NEM), which is a multimedia fate and transport model that is global in scale yet can achieve high spatial resolution of a user-defined target region without huge computational demands. Evaluating NEM by comparing model predictions for PCB-153 in air with measurements at nine long-term monitoring sites of the European Monitoring and Evaluation Programme (EMEP) reveals that nested simulations at a resolution of 1° × 1° yield results within a factor of 1.5 of observations at sites in northern Europe. At this resolution, the model attributes more than 90% of the atmospheric burden within any of the grid cells containing an EMEP site to advective atmospheric transport from elsewhere. Deteriorating model performance with decreasing resolution (15° × 15°, 5° × 5° and 1° × 1°), manifested by overestimation of concentrations across most of northern Europe by more than a factor of 3, illustrates the effect of numerical diffusion. Finally, we apply the model to demonstrate how the choice of spatial resolution affect predictions of atmospheric deposition to the Baltic Sea. While we envisage that NEM may be used for a wide range of applications in the future, further evaluation will be required to delineate the boundaries of applicability towards chemicals with divergent fate properties as well as in environmental media other than air.
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17.
  • Brännvall, Evelina, et al. (author)
  • Fly ash in landfill top covers : a review
  • 2016
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 18:1, s. 11-21
  • Journal article (peer-reviewed)abstract
    • Increase of energy recovery from municipal solid waste by incineration results in the increased amounts of incineration residues, such as fly ash, that have to be taken care of. Material properties should define whether fly ash is a waste or a viable resource to be used for various applications. Here, two areas of potential fly ash application are reviewed: the use of fly ash in a landfill top cover either as a liner material or as a soil amendment in vegetation layer. Fly ashes from incineration of three types of fuel are considered: refuse derived fuel (RDF), municipal solid waste incineration (MSWI) and biofuel. Based on the observations, RDF and MSWI fly ash is considered as suitable materials to be used in a landfill top cover liner. Whereas MSWI and biofuel fly ashes based on element availability for plant studies, could be considered suitable for the vegetation layer of the top cover. Responsible application of MSWI ashes is, however, warranted in order to avoid element accumulation in soil and elevation of background values over time.
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18.
  • Bui, Thuy T., et al. (author)
  • Applying a modified systematic review and integrated assessment framework (SYRINA) - a case study on triphenyl phosphate
  • 2023
  • In: Environmental Science. - 2050-7887 .- 2050-7895. ; 26:2, s. 380-399
  • Journal article (peer-reviewed)abstract
    • This work presents a case study in applying a systematic review framework (SYRINA) to the identification of chemicals as endocrine disruptors. The suitability and performance of the framework is tested with regard to the widely accepted World Health Organization definition of an endocrine disruptor (ED). The endocrine disrupting potential of triphenyl phosphate (TPP), a well-studied flame retardant reported to exhibit various endocrine related effects was assessed. We followed the 7 steps of the SYRINA framework, articulating the research objective via Populations, Exposures, Comparators, Outcomes (PECO) statements, performed literature search and screening, conducted study evaluation, performed data extraction and summarized and integrated the evidence. Overall, 66 studies, consisting of in vivo, in vitro and epidemiological data, were included. We concluded that triphenyl phosphate could be identified as an ED based on metabolic disruption and reproductive function. We found that the tools used in this case study and the optimizations performed on the framework were suitable to assess properties of EDs. A number of challenges and areas for methodological development in systematic appraisal of evidence relating to endocrine disrupting potential were identified; significant time and effort were needed for the analysis of in vitro mechanistic data in this case study, thus increasing the workload and time needed to perform the systematic review process. Further research and development of this framework with regards to grey literature (non-peer-reviewed literature) search, harmonization of study evaluation methods, more consistent evidence integration approaches and a pre-defined method to assess links between adverse effect and endocrine activity are recommended. It would also be advantageous to conduct more case studies for a chemical with less data than TPP.
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19.
  • Carlsson, Henrik, 1987-, et al. (author)
  • Combining the targeted and untargeted screening of environmental contaminants reveals associations between PFAS exposure and vitamin D metabolism in human plasma.
  • 2023
  • In: Environmental Science. - : Royal Society of Chemistry. - 2050-7887 .- 2050-7895. ; 25:6, s. 1116-1130
  • Journal article (peer-reviewed)abstract
    • We have developed, validated, and applied a method for the targeted and untargeted screening of environmental contaminants in human plasma using liquid chromatography high-resolution mass spectrometry (LC-HRMS). The method was optimized for several classes of environmental contaminants, including PFASs, OH-PCBs, HBCDs, and bisphenols. One-hundred plasma samples from blood donors (19-75 years, men n = 50, women n = 50, from Uppsala, Sweden) were analyzed. Nineteen targeted compounds were detected across the samples, with 18 being PFASs and the 19th being OH-PCB (4-OH-PCB-187). Ten compounds were positively associated with age (in order of increasing p-values: PFNA, PFOS, PFDA, 4-OH-PCB-187, FOSA, PFUdA, L-PFHpS, PFTrDA, PFDoA, and PFHpA; p-values ranging from 2.5 × 10-5 to 4.67 × 10-2). Three compounds were associated with sex (in order of increasing p-values: L-PFHpS, PFOS, and PFNA; p-values ranging from 1.71 × 10-2 to 3.88 × 10-2), all with higher concentrations in male subjects compared with female subjects. Strong correlations (0.56-0.93) were observed between long-chain PFAS compounds (PFNA, PFOS, PFDA, PFUdA, PFDoA, and PFTrDA). In the non-targeted data analysis, fourteen unknown features correlating with known PFASs were found (correlation coefficients 0.48-0.99). Five endogenous compounds were identified from these features, all correlating strongly with PFHxS (correlation coefficients 0.59-0.71). Three of the identified compounds were vitamin D3 metabolites, and two were diglyceride lipids (DG 24:6;O). The results demonstrate the potential of combining targeted and untargeted approaches to increase the coverage of compounds detected with a single method. This methodology is well suited for exposomics to detect previously unknown associations between environmental contaminants and endogenous compounds that may be important for human health.
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20.
  • Challis, Jonathan K., et al. (author)
  • Photodegradation of bitumen-derived organics in oil sands process-affected water
  • 2020
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 22:5, s. 1243-1255
  • Journal article (peer-reviewed)abstract
    • The chemical composition of water-soluble organics in oil sands process-affected water (OSPW) is primarily composed of natural constituents of bitumen that are solubilized and concentrated during aqueous extraction of oil sands. OSPW organics are persistent and acutely toxic, and a leading remediation strategy is long-term ageing in end-pit lakes, despite limited data available on its photochemical fate. Here, direct photolysis of whole OSPW, or of its constituent fractions, was examined at environmentally relevant wavelengths (>290 nm) in bench-top studies. Changes in the chemical profiles of whole OSPW, acid- (AEO), and base-extractable organics (BEO) were characterized by liquid chromatography with ultra-high resolution mass spectrometry in negative (-) and positive (+) ionization modes. Following 18 d of irradiation, photolysis reduced the total ion intensity in all samples in both modes. The most photo-labile species included the O-2(-), O-3(-), O-4(-), O2S-, and O4S- chemical classes, which were depleted in whole OSPW by 93-100% after only 5 d. In positive mode, detected species were more recalcitrant than those detected in negative mode, with an average reduction across all heteroatomic classes of 75 +/- 11.0% after 18 d. Estimated environmental half-lives for heteroatomic classes ranged from 57 d (O4S-) to 545 d (O3N+), with a greater recalcitrance for classes detected in positive mode compared to negative mode. Under field conditions in end-pit lakes, natural photolysis may be an important mechanism for effective OSPW remediation, and we suggest that future end-pit lakes be shallow to maximize light penetration and natural photolysis in ageing OSPW.
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21.
  • Chang, Li, et al. (author)
  • Recent progress in research on PM2.5 in subways.
  • 2021
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 23:5, s. 642-663
  • Journal article (peer-reviewed)abstract
    • Nowadays, PM2.5 concentrations greatly influence indoor air quality in subways and threaten passenger and staff health because PM2.5 not only contains heavy metal elements, but can also carry toxic and harmful substances due to its small size and large specific surface area. Exploring the physicochemical and distribution characteristics of PM2.5 in subways is necessary to limit its concentration and remove it. At present, there are numerous studies on PM2.5 in subways around the world, yet, there is no comprehensive and well-organized review available on this topic. This paper reviews the nearly twenty years of research and over 130 published studies on PM2.5 in subway stations, including aspects such as concentration levels and their influencing factors, physicochemical properties, sources, impacts on health, and mitigation measures. Although many determinants of station PM2.5 concentration have been reported in current studies, e.g., the season, outdoor environment, and station depth, their relative influence is uncertain. The sources of subway PM2.5 include those from the exterior (e.g., road traffic and fuel oil) and the interior (e.g., steel wheels and rails and metallic brake pads), but the proportion of these sources is also unknown. Control strategies of PM mainly include adequate ventilation and filtration, but these measures are often inefficient in removing PM2.5. The impacts of PM2.5 from subways on human health are still poorly understood. Further research should focus on long-term data collection, influencing factors, the mechanism of health impacts, and PM2.5 standards or regulations.
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22.
  • Chilkoor, Govinda, et al. (author)
  • Sustainability of renewable fuel infrastructure : a screening LCA case study of anticorrosive graphene oxide epoxy liners in steel tanks for the storage of biodiesel and its blends
  • 2017
  • In: Environmental Science. - : Royal Society of Chemistry. - 2050-7887 .- 2050-7895. ; 19:2, s. 141-153
  • Journal article (peer-reviewed)abstract
    • Biodiesel is a widely used fuel that meets the renewable fuel standards developed under Energy Policy Act of 2005. However, biodiesel is known to pose a series of abiotic and biotic corrosion risks to storage tanks. A typical practice (incumbent system) used to protect the tanks from the risks include: (i) coat the interior surface of the tank with solvent free epoxy (SFE) liner, and (ii) add a biocide in the tank. We present a screening-level, life cycle assessment study to evaluate and compare the environmental performance of graphene-oxide (GO)-epoxy (GOE) liner with the incumbent system. TRACI is used as an impact assessment tool to model midpoint environmental impacts for the ten categories: global warming potential (GWP, kg CO2 eq.); acidification potential (AP, kg SO2 eq.); potential human health damage impacts due to carcinogens (HH-CP, CTUh) and non-carcinogens (HH-NCP, CTUh); potential respiratory effects (REP, kg PM2.5 eq); eutrophication potential (EP, kg N eq); ozone depletion potential (ODP kg CFC-11 eq); ecotoxicity potential (ETXP, CTUe); smog formation potential (SFP kg O3 eq); and fossil fuel depletion potential (FFDP MJ surplus). The equivalent functional unit of the LCA study is designed to protect the 30 m2 of the interior surface (unalloyed steel sheet) of a 10,000 liters biodiesel tank against abiotic and biotic corrosion during its service life of 20 years. Overall, this LCA study highlights an improved environmental performance for the GOE liner compared to the incumbent system; GOE-liner system showed: 91% lower ODP impacts; 59% smaller for REP; 62% smaller for AP; 67-69% smaller for GWP and HH-CP; 72-76% smaller for EP, SFP, and FFDP; and 81-83% smaller for ETXP and HH-NCP categories. The scenario analysis study reveals that these potential impacts change by less than 15% when the GOE liners are functionalized with silanized-GO nanosheets or GO-reinforced, polyvinyl carbazole to improve the antimicrobial properties. The results from uncertainty analysis indicate that the impacts for the incumbent system are more sensitive to changes in key modeling parameters compared to that for GOE liner system.
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23.
  • Chirico, Nicola, et al. (author)
  • In silico approaches for the prediction of the breakthrough of organic contaminants in wastewater treatment plants
  • 2024
  • In: Environmental Science. - 2050-7887 .- 2050-7895. ; 26:2, s. 400-410
  • Journal article (peer-reviewed)abstract
    • The removal efficiency (RE) of organic contaminants in wastewater treatment plants (WWTPs) is a major determinant of the environmental impact of chemicals which are discharged to wastewater. In a recent study, non-target screening analysis was applied to quantify the percentage removal efficiency (RE%) of more than 300 polar contaminants, by analyzing influent and effluent samples from a Swedish WWTP with direct injection UHPLC-Orbitrap-MS/MS. Based on subsets extracted from these data, we developed quantitative structure–property relationships (QSPRs) for the prediction of WWTP breakthrough (BT) to the effluent water. QSPRs were developed by means of multiple linear regression (MLR) and were selected after checking for overfitting and chance relationships by means of bootstrap and randomization procedures. A first model provided good fitting performance, showing that the proposed approach for the development of QSPRs for the prediction of BT is reasonable. By further populating the dataset with similar chemicals using a Tanimoto index approach based on substructure count fingerprints, a second QSPR indicated that the prediction of BT is also applicable to new chemicals sufficiently similar to the training set. Finally, a class-specific QSPR for PEGs and PPGs showed BT prediction trends consistent with known degradation pathways.
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24.
  • Coll, Claudia, et al. (author)
  • Prospects for finding Junge variability-lifetime relationships for micropollutants in the Danube river
  • 2019
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 21:9, s. 1489-1497
  • Journal article (peer-reviewed)abstract
    • 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.
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25.
  • Cousins, Ian T., et al. (author)
  • Finding essentiality feasible : common questions and misinterpretations concerning the "essential-use" concept
  • 2021
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 23:8, s. 1079-1087
  • Research review (peer-reviewed)abstract
    • The essential-use concept is a tool that can guide the phase-out of per- and polyfluoroalkyl substances (PFAS) and potentially other substances of concern. This concept is a novel approach to chemicals management that determines whether using substances of concern, such as PFAS, is truly essential for a given functionality. To assess the essentiality of a particular use case, three considerations need to be addressed: (1) the function (chemical, end use and service) that the chemical provides in the use case, (2) whether the function is necessary for health and safety and critical for the functioning of society and (3) if the function is necessary, whether there are viable alternatives for the chemical for this particular use. A few illustrative examples of the three-step process are provided for use cases of PFAS. The essential-use concept takes chemicals management away from a substance-by-substance approach to a group approach. For PFAS and other substances of concern, it offers a more rapid pathway toward effective management or phase-out. Parts of the concept of essential use have already been widely applied in global treaties and international regulations and it has also been recently used by product manufacturers and retailers to phase out substances of concern from supply chains. Herein some of the common questions and misinterpretations regarding the practical application of the essential-use concept are reviewed, and answers and further clarifications are provided.
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26.
  • Cousins, Ian T., et al. (author)
  • Strategies for grouping per- and polyfluoroalkyl substances (PFAS) to protect human and environmental health
  • 2020
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 22:7, s. 1444-1460
  • Research review (peer-reviewed)abstract
    • Grouping strategies are needed for per- and polyfluoroalkyl substances (PFAS), in part, because it would be time and resource intensive to test and evaluate the more than 4700 PFAS on the global market on a chemical-by-chemical basis. In this paper we review various grouping strategies that could be used to inform actions on these chemicals and outline the motivations, advantages and disadvantages for each. Grouping strategies are subdivided into (1) those based on the intrinsic properties of the PFAS (e.g.persistence, bioaccumulation potential, toxicity, mobility, molecular size) and (2) those that inform risk assessment through estimation of cumulative exposure and/or effects. The most precautionary grouping approach of those reviewed within this article suggests phasing out PFAS based on their high persistence alone (the so-called P-sufficient approach). The least precautionary grouping approach reviewed advocates only grouping PFAS for risk assessment that have the same toxicological effects, modes and mechanisms of action, and elimination kinetics, which would need to be well documented across different PFAS. It is recognised that, given jurisdictional differences in chemical assessment philosophies and methodologies, no one strategy will be generally acceptable. The guiding question we apply to the reviewed grouping strategies is: grouping for what purpose? The motivation behind the grouping (e.g.determining use in productsvs.setting guideline levels for contaminated environments) may lead to different grouping decisions. This assessment provides the necessary context for grouping strategies such that they can be adopted as they are, or built on further, to protect human and environmental health from potential PFAS-related effects.
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27.
  • Cousins, Ian T., et al. (author)
  • The concept of essential use for determining when uses of PFASs can be phased out
  • 2019
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 21:11, s. 1803-1815
  • Research review (peer-reviewed)abstract
    • Because of the extreme persistence of per- and polyfluoroalkyl substances (PFASs) and their associated risks, the Madrid Statement argues for stopping their use where they are deemed not essential or when safer alternatives exist. To determine when uses of PFASs have an essential function in modern society, and when they do not, is not an easy task. Here, we: (1) develop the concept of essential use based on an existing approach described in the Montreal Protocol, (2) apply the concept to various uses of PFASs to determine the feasibility of elimination or substitution of PFASs in each use category, and (3) outline the challenges for phasing out uses of PFASs in society. In brief, we developed three distinct categories to describe the different levels of essentiality of individual uses. A phase-out of many uses of PFASs can be implemented because they are not necessary for the betterment of society in terms of health and safety, or because functional alternatives are currently available that can be substituted into these products or applications. Some specific uses of PFASs would be considered essential because they provide for vital functions and are currently without established alternatives. However, this essentiality should not be considered as permanent; rather, constant efforts are needed to search for alternatives. We provide a description of several ongoing uses of PFASs and discuss whether these uses are essential or non-essential according to the three essentiality categories. It is not possible to describe each use case of PFASs in detail in this single article. For follow-up work, we suggest further refining the assessment of the use cases of PFASs covered here, where necessary, and expanding the application of this concept to all other uses of PFASs. The concept of essential use can also be applied in the management of other chemicals, or groups of chemicals, of concern.
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28.
  • Cousins, Ian T., et al. (author)
  • The high persistence of PFAS is sufficient for their management as a chemical class
  • 2020
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 22:12, s. 2307-2312
  • Research review (peer-reviewed)abstract
    • Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic organic substances with diverse structures, properties, uses, bioaccumulation potentials and toxicities. Despite this high diversity, all PFAS are alike in that they contain perfluoroalkyl moieties that are extremely resistant to environmental and metabolic degradation. The vast majority of PFAS are therefore either non-degradable or transform ultimately into stable terminal transformation products (which are still PFAS). Under the European chemicals regulation this classifies PFAS as very persistent substances (vP). We argue that this high persistence is sufficient concern for their management as a chemical class, and for all non-essential uses of PFAS to be phased out. The continual release of highly persistent PFAS will result in increasing concentrations and increasing probabilities of the occurrence of known and unknown effects. Once adverse effects are identified, the exposure and associated effects will not be easily reversible. Reversing PFAS contamination will be technically challenging, energy intensive, and costly for society, as is evident in the efforts to remove PFAS from contaminated land and drinking water sources.
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29.
  • Cousins, Ian T., et al. (author)
  • Why is high persistence alone a major cause of concern?
  • 2019
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 21:5, s. 781-792
  • Research review (peer-reviewed)abstract
    • Persistence is a hazard criterion for chemicals enshrined in chemical regulation worldwide. In this paper, we argue that the higher the persistence of a chemical, the greater the emphasis that it should be given in chemicals assessment and decision making. We provide case studies for three classes of highly persistent chemicals (chlorofluorocarbons, polychlorinated biphenyls, and per-and polyfluoroalkyl substances) to exemplify problems unique to highly persistent chemicals, despite their otherwise diverse properties. Many well-known historical chemical pollution problems were the result of the release of highly persistent chemicals. Using evaluative modeling calculations, we demonstrate that if a chemical is highly persistent, its continuous release will lead to continuously increasing contamination irrespective of the chemical's physical-chemical properties. We argue that these increasing concentrations will result in increasing probabilities of the occurrence of known and unknown effects and that, once adverse effects are identified, it will take decades, centuries or even longer to reverse contamination and therefore effects. Based on our findings we propose that high persistence alone should be established as a sufficient basis for regulation of a chemical, which we term the P-sufficient approach. We argue that regulation on high persistence alone is not over-precautionary given the historical and ongoing problems that persistent chemicals have caused. Regulation of highly persistent chemicals, for example by restriction of emissions, would not only be precautionary, but would serve to prevent poorly reversible future impacts.
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30.
  • Dalmijn, Joost, et al. (author)
  • Emission inventory of PFASs and other fluorinated organic substances for the fluoropolymer production industry in Europe
  • 2024
  • In: Environmental Science. - 2050-7887 .- 2050-7895. ; 26:2, s. 269-287
  • Journal article (peer-reviewed)abstract
    • Fluoropolymers are a group of fluorinated polymers within the broad class of substances known as per- and polyfluoroalkyl substances (PFASs). During their production, a wide array of additional fluorinated organic substances (many PFASs and some not defined as PFASs) are used, formed and emitted to air and water. This study aims to assess, and make an inventory of, all emissions of PFASs and other fluorinated organic substances by the fluoropolymer production industry in Europe using available emission databases and permits. Air emissions of the fluorinated gases (i.e., chlorofluorocarbons, hydrofluorocarbons, hydrochlorofluorocarbons and perfluorocarbons (CFCs, H(C)FCs and PFCs)) by this industry have reportedly decreased between 2007 and 2021 from roughly 500 to 150 tonnes per year. Emissions of fluorosurfactants to air and water have also been reduced significantly. However, large uncertainties remain regarding the emissions of substances that are neither fluorinated gases nor fluorosurfactants but are classified as PFASs, such as polymerization by-products, chain transfer agents and fluorinated solvents. The available data indicate that the release of these substances is not decreasing but remains relatively stable. As this inventory probably underestimates emissions, further research, improved data availability and more harmonized reporting of emissions are necessary to obtain more accurate emission data for these substances. Nevertheless, based on the available data, it is clear that the emissions from fluoropolymer production plants to air and water are still significant and that the production of fluoropolymers continues to introduce persistent substances to the environment. This study assesses the environmental impact of the fluoropolymer industry in Europe by making an inventory of their emissions of PFASs and other fluorinated organic substances.
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31.
  • de Wit, Cynthia A., 1956-, et al. (author)
  • Influence of climate change on persistent organic pollutants and chemicals of emerging concern in the Arctic : state of knowledge and recommendations for future research
  • 2022
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 24:10, s. 1530-1543
  • Research review (peer-reviewed)abstract
    • Persistent organic pollutants (POPs) have accumulated in polar environments as a result of long-range transport from urban/industrial and agricultural source regions in the mid-latitudes. Climate change has been recognized as a factor capable of influencing POP levels and trends in the Arctic, but little empirical data have been available previously. A growing number of recent studies have now addressed the consequences of climate change for the fate of Arctic contaminants, as reviewed and assessed by the Arctic Monitoring and Assessment Programme (AMAP). For example, correlations between POP temporal trends in air or biota and climate indices, such as the North Atlantic Oscillation Index, have been found. Besides the climate indices, temperature, precipitation and sea-ice were identified as important climate parameters influencing POP levels in the Arctic environment. However, the physical changes are interlinked with complex ecological changes, including new species habitats and predator/prey relationships, resulting in a vast diversity of processes directly or indirectly affecting levels and trends of POPs. The reviews in this themed issue illustrate that the complexity of physical, chemical, and biological processes, and the rapid developments with regard to both climate change and chemical contamination, require greater interdisciplinary scientific exchange and collaboration. While some climate and biological parameters have been linked to POP levels in the Arctic, mechanisms underlying these correlations are usually not understood and need more work. Going forward there is a need for a stronger collaborative approach to understanding these processes due to high uncertainties and the incremental process of increasing knowledge of these chemicals. There is also a need to support and encourage community-based studies and the co-production of knowledge, including the utilization of Indigenous Knowledge, for interpreting trends of POPs in light of climate change.
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32.
  • de Wit, Cynthia A., et al. (author)
  • Mass balance study of brominated flame retardants in female captive peregrine falcons
  • 2019
  • In: Environmental Science-Processes & Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 21:7, s. 1115-1131
  • Journal article (peer-reviewed)abstract
    • Little is known about brominated flame retardant (BFR) dynamics in birds, especially large molecules such as decabromodiphenyl ether (BDE-209). In particular, bioaccumulation from food and transfer dynamics to eggs are poorly understood. Therefore, an input-output mass balance study of tri-decaBDEs, DBDPE and HBCDD was performed in three female peregrine falcons from a captive breeding program by analyzing their naturally contaminated food (quail, chicken (cockerels)), plasma, feces and eggs. Predominant BFRs in cockerels and quail were BDE-209 and DBDPE, as well as HBCDD in quail. The predominant BFRs found in falcon plasma were BDE-209, -153 and -183, in eggs, HBCDD, BDE-209 and -153 and in feces, BDE-209. Mean absorption efficiencies (AE) for the tetra-octabrominated BDEs ranged from 84-100% and 70% for HBCDD. The AEs for BDE-206, -207, -208 and -209 varied due to the large variability seen for feces fluxes. All egg/plasma ratios for BDEs were similar and greater than one (range 1.1-2.7), including for BDE-209, indicating efficient transfer from females to the eggs. Excretion via egg-laying was approximately 6.0-29% of the initial, pre-breeding body burden of individual penta-decaBDE congeners, (15-45% for BDE-206). HBCDD was not detected in plasma but was found in eggs, also indicating efficient transfer and excretion via eggs. Input fluxes from food exceeded the output fluxes (feces, eggs) indicating considerable metabolism for tetra-octaBDEs, possibly also for the nona-decaBDEs and HBCDD. Bioaccumulation factors calculated from lipid weight concentrations in plasma and food (BAF(p)) were highest for BDE-208 (31), -153 (23), -209 (19) and -207 (16) and from eggs and food (BAF(e)), were highest for HBCDD (140), BDE-153 (41), -208 (42), BDE-207 (24) and BDE-209 (21). BAF(e) and BAF(p) values were below 10 for BDE-47, -99 and -100. For one falcon, egg results were available from three different years and estimated half-lives were 65 d (BDE-99), 624 d (BDE-153), 31 d (BDE-154), 349 d (BDE-183), 77 d (BDE-196) and 89 d (BDE-197).
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33.
  • Di Guardo, Antonio, et al. (author)
  • Environmental fate and exposure models : advances and challenges in 21st century chemical risk assessment
  • 2018
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 20:1, s. 58-71
  • Research review (peer-reviewed)abstract
    • Environmental fate and exposure models are a powerful means to integrate information on chemicals, their partitioning and degradation behaviour, the environmental scenario and the emissions in order to compile a picture of chemical distribution and fluxes in the multimedia environment. A 1995 pioneering book, resulting from a series of workshops among model developers and users, reported the main advantages and identified needs for research in the field of multimedia fate models. Considerable efforts were devoted to their improvement in the past 25 years and many aspects were refined; notably the inclusion of nanomaterials among the modelled substances, the development of models at different spatial and temporal scales, the estimation of chemical properties and emission data, the incorporation of additional environmental media and processes, the integration of sensitivity and uncertainty analysis in the simulations. However, some challenging issues remain and require research efforts and attention: the need of methods to estimate partition coefficients for polar and ionizable chemical in the environment, a better description of bioavailability in different environments as well as the requirement of injecting more ecological realism in exposure predictions to account for the diversity of ecosystem structures and functions in risk assessment. Finally, to transfer new scientific developments into the realm of regulatory risk assessment, we propose the formation of expert groups that compare, discuss and recommend model modifications and updates and help develop practical tools for risk assessment. Environmental significance Multimedia environmental fate models are regularly employed in the risk assessment of chemicals. They historically evolved from simple approaches to more refined and integrated modeling tools, often provided as part of a tiered strategy. Much work has been devoted to improving various aspects at the process and environmental description levels, but some issues need further research and model development, such as the capability to properly simulate the behaviour of polar and ionizable chemicals in the environment, the biovailability of chemicals in aquatic and terrestrial environments, and variability in time and space to account for more ecological relevance. At the same time, it is important to avoid paralysis by analysis and develop practical tools for regulatory risk assessment that are fit for purpose. We propose the formation of expert groups to address this task.
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34.
  • Droge, Steven T. J., et al. (author)
  • Screening the baseline fish bioconcentration factor of various types of surfactants using phospholipid binding data
  • 2021
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 23:12
  • Journal article (peer-reviewed)abstract
    • Fish bioconcentration factors (BCFs) are commonly used in chemical hazard and risk assessment. For neutral organic chemicals BCFs are positively correlated with the octanol-water partition ratio (K-OW), but K-OW is not a reliable parameter for surfactants. Membrane lipid-water distribution ratios (D-MLW) can be accurately measured for all kinds of surfactants, using phospholipid-based sorbents. This study first demonstrates that D-MLW values for ionic surfactants are more than 100 000 times higher than the partition ratio to fish-oil, representing neutral storage lipid. A non-ionic alcohol ethoxylate surfactant showed almost equal affinity for both lipid types. Accordingly, a baseline screening BCF value for surfactants (BCFbaseline) can be approximated for ionic surfactants by multiplying D-MLW by the phospholipid fraction in tissue, and for non-ionic surfactants by multiplying D-MLW by the total lipid fraction. We measured D-MLW values for surfactant structures, including linear and branched alkylbenzenesulfonates, an alkylsulfoacetate and an alkylethersulfate, bis(2-ethylhexyl)-surfactants (e.g., docusate), zwitterionic alkylbetaines and alkylamine-oxides, and a polyprotic diamine. Together with sixty previously published D-MLW values for surfactants, structure-activity relationships were derived to elucidate the influence of surfactant specific molecular features on D-MLW. For 23 surfactant types, we established the alkyl chain length at which BCFbaseline would exceed the EU REACH bioaccumulation (B) threshold of 2000 L kg(-1), and would therefore require higher tier assessments to further refine the BCF estimate. Finally, the derived BCFbaseline are compared with measured literature in vivo BCF data where available, suggesting that refinements, most notably reliable estimates of biotransformation rates, are needed for most surfactant types.
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35.
  • Fang, Shuhong, et al. (author)
  • Levels of per- and polyfluoroalkyl substances (PFAS) in ski wax products on the market in 2019 indicate no changes in formulation
  • 2020
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 22:11, s. 2142-2146
  • Journal article (peer-reviewed)abstract
    • In the summer of 2019, eleven of the best-selling fluorinated ski wax products were purchased from one of Norway's largest sports stores and soon after analysed for a suite of 26 per- and polyfluoroalkyl substances (PFAS). The waxes were shown to contain a wide range of perfluoroalkyl acids, including perfluoroalkyl carboxylic acids with up to 25 carbons. Of particular concern was the finding that perfluorooctanoic acid (PFOA) levels in nine of the eleven ski lubrication products analysed were above the EU limit values of 25 ng g(-1), which came into force on 4(th) July 2020. The ski wax with the highest PFOA levels had a concentration that was 1215 times higher than the EU restrictions. Although some of the ski wax manufacturers have indicated that they have switched to formulations that contain chemistries based on shorter perfluoroalkyl chains, the analytical results show that this is not the case.
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36.
  • Felizeter, Sebastian, et al. (author)
  • Uptake of perfluorinated alkyl acids by crops : results from a field study
  • 2021
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 23:8, s. 1158-1170
  • Journal article (peer-reviewed)abstract
    • Four crops with different edible plant parts (radish, lettuce, pea and maize) were grown in outdoor lysimeters on soil spiked with 13 perfluorinated alkyl acids (PFAAs) at 4 different levels. PFAA concentrations were measured in soil, soil pore water, and different plant parts at harvest. Edible part/soil concentration factors ranged over seven orders of magnitude and decreased strongly with increasing PFAA chain length, by a factor of 10 for each additional fluorinated carbon (n(CF)) for pea. Three processes were responsible for most of the variability. The first was sorption to soil; calculating whole plant concentration factors on the basis of concentration in pore water instead of soil reduced the variability from five orders of magnitude to two. Second, the journey of the PFAAs with the transpiration stream to the leaves was hindered by retention in the roots driven by sorption; root retention factors increased by a factor 1.7 for each n(CF). Third, transfer of PFAAs from the leaves to the fruit via the phloem flow was also hindered - presumably by sorption; fruit/leaf concentration factors decreased by a factor 2.5 for each n(CF). A simple mathematical model based on the above principles described the measured concentrations in roots, leaves, fruits and radish bulbs within a factor 4 in most cases. This indicates that the great diversity in PFAA transfer from soil to crops can be largely described with simple concepts for four markedly different species.
  •  
37.
  • Fu, Xi, et al. (author)
  • Associations between environmental characteristics, high-resolution indoor microbiome, metabolome and allergic and non-allergic rhinitis symptoms for junior high school students
  • 2023
  • In: Environmental Science. - : Royal Society of Chemistry. - 2050-7887 .- 2050-7895. ; 25:4, s. 791-804
  • Journal article (peer-reviewed)abstract
    • Rhinitis is one of the most prevalent chronic diseases globally. Microbiome exposure affects the occurrence of rhinitis. However, previous studies did not differentiate allergic rhinitis (AR) and non-allergic rhinitis (NAR) in the microbial association analysis. In this study, we investigate 347 students in 8 junior high schools, Terengganu, Malaysia, who were categorized as healthy (70.9%), AR (13.8%) and NAR (15.3%) based on a self-administered questionnaire and skin prick tests of pollen, pet, mould and house dust mite allergens. Classroom microbial and metabolite exposure in vacuumed dust was characterized by PacBio long-read amplicon sequencing, quantitative PCR and LC-MS-based untargeted metabolomics. Our findings indicate a similar microbial association pattern between AR and NAR. The richness in Gammaproteobacteria was negatively associated with AR and NAR symptoms, whereas total fungal richness was positively associated with AR and NAR symptoms (p < 0.05). Brasilonema bromeliae and Aeromonas enteropelogenes were negatively associated with AR and NAR, and Deinococcus was positively associated with AR and NAR (p < 0.01). Pipecolic acid was protectively associated with AR and NAR symptoms (OR = 0.06 and 0.13, p = 0.009 and 0.045). A neural network analysis showed that B. bromeliae was co-occurring with pipecolic acid, suggesting that the protective role of this species may be mediated by releasing pipecolic acid. Indoor relative humidity and the weight of vacuum dust were associated with AR and NAR, respectively (p < 0.05), but the health effects were mediated by two protective bacterial species, Aliinostoc morphoplasticum and Ilumatobacter fluminis. Overall, our study reported a similar microbial association pattern between AR and NAR and also revealed the complex interactions between microbial species, environmental characteristics, and rhinitis symptoms.
  •  
38.
  • Fu, Xi, et al. (author)
  • Associations between the indoor microbiome, environmental characteristics and respiratory infections in junior high school students of Johor Bahru, Malaysia.
  • 2021
  • In: Environmental Science. - : Royal Society of Chemistry. - 2050-7887 .- 2050-7895. ; 23:8, s. 1171-1181
  • Journal article (peer-reviewed)abstract
    • Pathogens are commonly present in the human respiratory tract, but symptoms are varied among individuals. The interactions between pathogens, commensal microorganisms and host immune systems are important in shaping the susceptibility, development and severity of respiratory diseases. Compared to the extensive studies on the human microbiota, few studies reported the association between indoor microbiome exposure and respiratory infections. In this study, 308 students from 21 classrooms were randomly selected to survey the occurrence of respiratory infections in junior high schools of Johor Bahru, Malaysia. Vacuum dust was collected from the floor, chairs and desks of these classrooms, and high-throughput amplicon sequencing (16S rRNA and ITS) and quantitative PCR were conducted to characterize the absolute concentration of the indoor microorganisms. Fifteen bacterial genera in the classes Actinobacteria, Alphaproteobacteria, and Cyanobacteria were protectively associated with respiratory infections (p < 0.01), and these bacteria were mainly derived from the outdoor environment. Previous studies also reported that outdoor environmental bacteria were protectively associated with chronic respiratory diseases, such as asthma, but the genera identified were different between acute and chronic respiratory diseases. Four fungal genera from Ascomycota, including Devriesia, Endocarpon, Sarcinomyces and an unclassified genus from Herpotrichillaceae, were protectively associated with respiratory infections (p < 0.01). House dust mite (HDM) allergens and outdoor NO2 concentration were associated with respiratory infections and infection-related microorganisms. A causal mediation analysis revealed that the health effects of HDM and NO2 were partially or fully mediated by the indoor microorganisms. This is the first study to explore the association between environmental characteristics, microbiome exposure and respiratory infections in a public indoor environment, expanding our understanding of the complex interactions among these factors.
  •  
39.
  • Fu, Xi, et al. (author)
  • Furry pet allergens, fungal DNA and microbial volatile organic compounds (MVOCs) in the commercial aircraft cabin environment
  • 2013
  • In: Environmental Science: Processes & Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 15:6, s. 1228-1234
  • Journal article (peer-reviewed)abstract
    • There has been concern about the cabin environment in commercial aircraft. We measured cat, dog and horse allergens and fungal DNA in cabin dust and microbial volatile organic compounds (MVOCs) in cabin air. Samples were collected from two European airline companies, one with cabins having textile seats (TSC) and the other with cabins having leather seats (LSC), 9 airplanes from each company. Dust was vacuumed from seats and floors in the flight deck and different parts of the cabin. Cat (Fel d1), dog (Can f1) and horse allergens (Equ cx) were analyzed by ELISA. Five sequences of fungal DNA were analyzed by quantitative PCR. MVOCs were sampled on charcoal tubes in 42 TSC flights, and 17 compounds were analyzed by gas chromatography mass spectrometry (GC-MS) with selective ion monitoring (SIM). MVOC levels were compared with levels in homes from Nordic countries. The weight of dust was 1.8 times larger in TSC cabins as compared to LSC cabins (p < 0.001). In cabins with textile seats, the geometric mean (GM) concentrations of Fel d1, Can f1 and Equ cx were 5359 ng g(-1), 6067 ng g(-1), and 13 703 ng g(-1) (GM) respectively. Levels of Fel d1, Can f1 and Equ cx were 50 times, 27 times and 75 times higher respectively, in TSC cabins as compared to LSC cabins (p < 0.001). GM levels of Aspergillus/Penicillium DNA, Aspergillus versicolor DNA, Stachybotrys chartarum DNA and Streptomyces DNA were all higher in TSC as compared to LSC (p < 0.05). The sum of MVOCs in cabin air (excluding butanols) was 3192 ng m(-3) (GM), 3.7 times higher than in homes (p < 0.001) and 2-methyl-1-butanol and 3-methyl-1-butanol concentrations were 15-17 times higher as compared to homes (p < 0.001). Concentrations of isobutanol, 1-butanol, dimethyldisulfide, 2-hexanone, 2-heptanone, 3-octanone, isobutyl acetate and ethyl-2-methylbutyrate were lower in cabin air as compared to homes (p < 0.05). In conclusion, textile seats are much more contaminated by pet allergens and fungal DNA than leather seats. The use of seats with smooth surfaces should be encouraged. The MVOC levels differed between cabin air and homes.
  •  
40.
  • Futter, Martyn (author)
  • A theoretical assessment of microplastic transport in river catchments and their retention by soils and river sediments
  • 2016
  • In: Environmental Science: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 18, s. 1050-1059
  • Journal article (peer-reviewed)abstract
    • The presence of microplastics (MPs) in the environment is a problem of growing concern. While research has focused on MP occurrence and impacts in the marine environment, very little is known about their release on land, storage in soils and sediments and transport by run-off and rivers. This study describes a first theoretical assessment of these processes. A mathematical model of catchment hydrology, soil erosion and sediment budgets was upgraded to enable description of MP fate. The Thames River in the UK was used as a case study. A general lack of data on MP emissions to soils and rivers and the mass of MPs in agricultural soils, limits the present work to serve as a purely theoretical, nevertheless rigorous, assessment that can be used to guide future monitoring and impact evaluations. The fundamental assumption on which modelling is based is that the same physical controls on soil erosion and natural sediment transport (for which model calibration and validation are possible), also control MP transport and storage. Depending on sub-catchment soil characteristics and precipitation patterns, approximately 16-38% of the heavier-than-water MPs hypothetically added to soils (e.g. through routine applications of sewage sludge) are predicted to be stored locally. In the stream, MPs < 0.2 mm are generally not retained, regardless of their density. Larger MPs with densities marginally higher than water can instead be retained in the sediment. It is, however, anticipated that high flow periods can remobilize this pool. Sediments of river sections experiencing low stream power are likely hotspots for deposition of MPs. Exposure and impact assessments should prioritize these environments.
  •  
41.
  • Futter, Martyn (author)
  • Assessing the impacts of climate change and socio-economic changes on flow and phosphorus flux in the Ganga river system
  • 2015
  • In: Environmental Science: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 17, s. 1098-1110
  • Journal article (peer-reviewed)abstract
    • Anthropogenic climate change has impacted and will continue to impact the natural environment and people around the world. Increasing temperatures and altered rainfall patterns combined with socio-economic factors such as population changes, land use changes and water transfers will affect flows and nutrient fluxes in river systems. The Ganga river, one of the largest river systems in the world, supports approximately 10% global population and more than 700 cities. Changes in the Ganga river system are likely to have a significant impact on water availability, water quality, aquatic habitats and people. In order to investigate these potential changes on the flow and water quality of the Ganga river, a multi-branch version of INCA Phosphorus (INCA-P) model has been applied to the entire river system. The model is used to quantify the impacts from a changing climate, population growth, additional agricultural land, pollution control and water transfers for 2041-2060 and 2080-2099. The results provide valuable information about potential effects of different management strategies on catchment water quality.
  •  
42.
  • Futter, Martyn (author)
  • Dynamic modeling of the Ganga river system: impacts of future climate and socio-economic change on flows and nitrogen fluxes in India and Bangladesh
  • 2015
  • In: Environmental Science: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 17, s. 1082-1097
  • Journal article (peer-reviewed)abstract
    • This study investigates the potential impacts of future climate and socio-economic change on the flow and nitrogen fluxes of the Ganga river system. This is the first basin scale water quality study for the Ganga considering climate change at 25 km resolution together with socio-economic scenarios. The revised dynamic, process-based INCA model was used to simulate hydrology and water quality within the complex multi-branched river basins. All climate realizations utilized in the study predict increases in temperature and rainfall by the 2050s with significant increase by the 2090s. These changes generate associated increases in monsoon flows and increased availability of water for groundwater recharge and irrigation, but also more frequent flooding. Decreased concentrations of nitrate and ammonia are expected due to increased dilution. Different future socio-economic scenarios were found to have a significant impact on water quality at the downstream end of the Ganga. A less sustainable future resulted in a deterioration of water quality due to the pressures from higher population growth, land use change, increased sewage treatment discharges, enhanced atmospheric nitrogen deposition, and water abstraction. However, water quality was found to improve under a more sustainable strategy as envisaged in the Ganga clean-up plan.
  •  
43.
  • Futter, Martyn (author)
  • Impacts of climate change and socio-economic scenarios on flow and water quality of the Ganges, Brahmaputra and Meghna (GBM) river systems: low flow and flood statistics
  • 2015
  • In: Environmental Science: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 17, s. 1057-1069
  • Journal article (peer-reviewed)abstract
    • The potential impacts of climate change and socio-economic change on flow and water quality in rivers worldwide is a key area of interest. The Ganges-Brahmaputra-Meghna (GBM) is one of the largest river basins in the world serving a population of over 650 million, and is of vital concern to India and Bangladesh as it provides fresh water for people, agriculture, industry, conservation and for the delta system downstream. This paper seeks to assess future changes in flow and water quality utilising a modelling approach as a means of assessment in a very complex system. The INCA-N model has been applied to the Ganges, Brahmaputra and Meghna river systems to simulate flow and water quality along the rivers under a range of future climate conditions. Three model realisations of the Met Office Hadley Centre global and regional climate models were selected from 17 perturbed model runs to evaluate a range of potential futures in climate. In addition, the models have also been evaluated using socioeconomic scenarios, comprising (1) a business as usual future, (2) a more sustainable future, and (3) a less sustainable future. Model results for the 2050s and the 2090s indicate a significant increase in monsoon flows under the future climates, with enhanced flood potential. Low flows are predicted to fall with extended drought periods, which could have impacts on water and sediment supply, irrigated agriculture and saline intrusion. In contrast, the socio-economic changes had relatively little impact on flows, except under the low flow regimes where increased irrigation could further reduce water availability. However, should large scale water transfers upstream of Bangladesh be constructed, these have the potential to reduce flows and divert water away from the delta region depending on the volume and timing of the transfers. This could have significant implications for the delta in terms of saline intrusion, water supply, agriculture and maintaining crucial ecosystems such as the mangrove forests, with serious implications for people's livelihoods in the area. The socio-economic scenarios have a significant impact on water quality, altering nutrient fluxes being transported into the delta region.
  •  
44.
  • Futter, Martyn (author)
  • Modelling metaldehyde in catchments: a River Thames case-study
  • 2017
  • In: Environmental Science: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 19, s. 586-595
  • Journal article (peer-reviewed)abstract
    • The application of metaldehyde to agricultural catchment areas to control slugs and snails has caused severe problems for drinking water supply in recent years. In the River Thames catchment, metaldehyde has been detected at levels well above the EU and UK drinking water standards of 0.1 mu g l(-1) at many sites across the catchment between 2008 and 2015. Metaldehyde is applied in autumn and winter, leading to its increased concentrations in surface waters. It is shown that a process-based hydro-biogeochemical transport model (INCA-contaminants) can be used to simulate metaldehyde transport in catchments from areas of application to the aquatic environment. Simulations indicate that high concentrations in the river system are a direct consequence of excessive application rates. A simple application control strategy for metaldehyde in the Thames catchment based on model results is presented.
  •  
45.
  • Futter, Martyn (author)
  • Rainfall runoff modelling of the Upper Ganga and Brahmaputra basins using PERSiST
  • 2015
  • In: Environmental Science: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 17, s. 1070-1081
  • Journal article (peer-reviewed)abstract
    • There are ongoing discussions about the appropriate level of complexity and sources of uncertainty in rainfall runoff models. Simulations for operational hydrology, flood forecasting or nutrient transport all warrant different levels of complexity in the modelling approach. More complex model structures are appropriate for simulations of land-cover dependent nutrient transport while more parsimonious model structures may be adequate for runoff simulation. The appropriate level of complexity is also dependent on data availability. Here, we use PERSiST; a simple, semi-distributed dynamic rainfall-runoff modelling toolkit to simulate flows in the Upper Ganges and Brahmaputra rivers. We present two sets of simulations driven by single time series of daily precipitation and temperature using simple (A) and complex (B) model structures based on uniform and hydrochemically relevant land covers respectively. Models were compared based on ensembles of Bayesian Information Criterion (BIC) statistics. Equifinality was observed for parameters but not for model structures. Model performance was better for the more complex (B) structural representations than for parsimonious model structures. The results show that structural uncertainty is more important than parameter uncertainty. The ensembles of BIC statistics suggested that neither structural representation was preferable in a statistical sense. Simulations presented here confirm that relatively simple models with limited data requirements can be used to credibly simulate flows and water balance components needed for nutrient flux modelling in large, data-poor basins.
  •  
46.
  • Gewert, Berit, et al. (author)
  • Pathways for degradation of plastic polymers floating in the marine environment
  • 2015
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 17:9, s. 1513-1521
  • Research review (peer-reviewed)abstract
    • Each year vast amounts of plastic are produced worldwide. When released to the environment, plastics accumulate, and plastic debris in the world's oceans is of particular environmental concern. More than 60% of all floating debris in the oceans is plastic and amounts are increasing each year. Plastic polymers in the marine environment are exposed to sunlight, oxidants and physical stress, and over time they weather and degrade. The degradation processes and products must be understood to detect and evaluate potential environmental hazards. Some attention has been drawn to additives and persistent organic pollutants that sorb to the plastic surface, but so far the chemicals generated by degradation of the plastic polymers themselves have not been well studied from an environmental perspective. In this paper we review available information about the degradation pathways and chemicals that are formed by degradation of the six plastic types that are most widely used in Europe. We extrapolate that information to likely pathways and possible degradation products under environmental conditions found on the oceans' surface. The potential degradation pathways and products depend on the polymer type. UV-radiation and oxygen are the most important factors that initiate degradation of polymers with a carbon-carbon backbone, leading to chain scission. Smaller polymer fragments formed by chain scission are more susceptible to biodegradation and therefore abiotic degradation is expected to precede biodegradation. When heteroatoms are present in the main chain of a polymer, degradation proceeds by photo-oxidation, hydrolysis, and biodegradation. Degradation of plastic polymers can lead to low molecular weight polymer fragments, like monomers and oligomers, and formation of new end groups, especially carboxylic acids.
  •  
47.
  • Glüge, Juliane, et al. (author)
  • An overview of the uses of per- and polyfluoroalkyl substances (PFAS)
  • 2020
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 22:12, s. 2345-2373
  • Journal article (peer-reviewed)abstract
    • Per- and polyfluoroalkyl substances (PFAS) are of concern because of their high persistence (or that of their degradation products) and their impacts on human and environmental health that are known or can be deduced from some well-studied PFAS. Currently, many different PFAS (on the order of several thousands) are used in a wide range of applications, and there is no comprehensive source of information on the many individual substances and their functions in different applications. Here we provide a broad overview of many use categories where PFAS have been employed and for which function; we also specify which PFAS have been used and discuss the magnitude of the uses. Despite being non-exhaustive, our study clearly demonstrates that PFAS are used in almost all industry branches and many consumer products. In total, more than 200 use categories and subcategories are identified for more than 1400 individual PFAS. In addition to well-known categories such as textile impregnation, fire-fighting foam, and electroplating, the identified use categories also include many categories not described in the scientific literature, including PFAS in ammunition, climbing ropes, guitar strings, artificial turf, and soil remediation. We further discuss several use categories that may be prioritised for finding PFAS-free alternatives. Besides the detailed description of use categories, the present study also provides a list of the identified PFAS per use category, including their exact masses for future analytical studies aiming to identify additional PFAS.
  •  
48.
  • Glynn, A., et al. (author)
  • Determinants of serum concentrations of perfluoroalkyl acids (PFAAs) in school children and the contribution of low-level PFAA-contaminated drinking water
  • 2020
  • In: Environmental Science-Processes & Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 22:4, s. 930-944
  • Journal article (peer-reviewed)abstract
    • Little is known about the demographic/life-style/physiological determinants explaining the variation of serum perfluoroalkyl acid (PFAA) concentrations in children. We identified significant determinants in children and investigated the influence of low-level PFAA-contaminated drinking water (DW) (<10 ng L(-1)of single PFAAs) on serum concentrations. Four perfluorosulfonic acids (PFSAs) and 11 perfluorocarboxylic acids (PFCAs) were analyzed in serum from 5(th)grade children from 11 Swedish schools (N= 200; average age: 12 years) using liquid chromatography-tandem-mass-spectrometry. Data on demography and life-style/physiological factors were obtained by questionnaires. PFAA concentrations in raw and drinking water (DW) were obtained from the water works supplying DW to the schools. In multiple regression analyses school was the determinant contributing most to the variation in PFAA concentrations, with the lowest contribution for PFHpA (10%) and the highest for PFHxS (81%). Girls had lower adjusted mean concentrations of PFHxS, PFOS, PFNA and PFDA than boys, but a higher concentration of PFHxA. Girls reporting onset of menstruation had lower PFHxS and PFOA concentrations than other girls, suggesting menstrual bleeding elimination. Children born by mothers from less industrialized countries had lower mean concentrations of both PFSAs and PFCAs than children with mothers from highly industrialized countries, suggesting differences in early-life exposure. Life-style factors associated with paternal education levels appeared to influence PFAA concentrations differently than maternal education level. Already at an average DW PFHxS concentration of 2 ng L-1, children had a significantly higher adjusted mean serum PFHxS concentration than at an average DW concentration of <1.6 ng PFHxS L-1. Similar results were observed for PFOS and PFOA. The DW variable explained 16% (PFOA) to 78% (PFHxS) of the variation in serum PFAA concentrations, suggesting that low-level-contaminated DW is a significant source of exposure for children in Sweden. Although some of the associations, especially those with menstruation and maternal birth country, should be interpreted with extra caution due to the small size of the study, the results contribute to future work on identifying populations of children at risk of elevated PFAA exposures.
  •  
49.
  • Gonzalez, N. J. D., et al. (author)
  • Primary and secondary organics in the tropical Amazonian rainforest aerosols : chiral analysis of 2-methyltetraols
  • 2014
  • In: ENVIRON SCI-PROC IMP. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 16:6, s. 1413-1421
  • Journal article (peer-reviewed)abstract
    • This work presents the application of a new method to facilitate the distinction between biologically produced (primary) and atmospherically produced (secondary) organic compounds in ambient aerosols based on their chirality. The compounds chosen for this analysis were the stereomers of 2-methyltetraols, (2R, 3S)- and (2S, 3R)-methylerythritol, (L- and D-form, respectively), and (2S, 3S)- and (2R, 3R)-methylthreitol (L- and D-form), shown previously to display some enantiomeric excesses in atmospheric aerosols, thus to have at least a partial biological origin. In this work PM10 aerosol fractions were collected in a remote tropical rainforest environment near Manaus, Brazil, between June 2008 and June 2009 and analysed. Both 2-methylerythritol and 2-methylthreitol displayed a net excess of one enantiomer (either the L- or the D-form) in 60 to 72% of these samples. These net enantiomeric excesses corresponded to compounds entirely biological but accounted for only about 5% of the total 2-methyltetrol mass in all the samples. Further analysis showed that, in addition, a large mass of the racemic fractions (equal mixtures of D- and L-forms) was also biological. Estimating the contribution of secondary reactions from the isomeric ratios measured in the samples (=ratios 2-methylthreitol over 2-methylerythritol), the mass fraction of secondary methyltetrols in these samples was estimated to a maximum of 31% and their primary fraction to a minimum of 69%. Such large primary fractions could have been expected in PM10 aerosols, largely influenced by biological emissions, and would now need to be investigated in finer aerosols. This work demonstrates the effectiveness of chiral and isomeric analyses as the first direct tool to assess the primary and secondary fractions of organic aerosols.
  •  
50.
  • Goss, Matthew, et al. (author)
  • A simple field-based biodegradation test shows pH to be an inadequately controlled parameter in laboratory biodegradation testing
  • 2020
  • In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 22:4, s. 1006-1013
  • Journal article (peer-reviewed)abstract
    • Biodegradation tests are essential for characterizing the behavior of organic micropollutants in the environment, but they are carried out almost exclusively in the laboratory. Test parameters such as temperature and test chemical concentration are often applied in ways that affect observed biodegradation, and laboratory testing requires sophisticated temperature-controlled facilities. We developed a field-based test based on OECD 309 which minimizes the need for laboratory resources such as temperature-controlled facilities by using bottles incubated in the natural water body. The test also utilized contaminant residues present in unspiked natural water to increase the relevance of the results to the local system. A test in a local river and a matching lab-based test were conducted in parallel. We quantified 26 of 40 targeted micropollutants and observed dissipation for 13. Significant differences in half-life (up to a factor of 3.5) between lab and field bottles were observed for 7 compounds, with 6 of 7 degrading more slowly in field bottles. For 4 of these, dissipation was positively correlated to the neutral fraction of the chemical. Differences in the neutral fraction arose due to a higher pH in the lab bottles induced by outgassing of CO2 from the oversaturated river water. We conclude that pH is an important parameter to control in biodegradation testing and that field-based tests may be more environmentally relevant.
  •  
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