Norwegian Geotechnical Institute (NGI) Digital Archive
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Persistent, mobile and toxic (PMT) and very persistent and very mobile (vPvM) substances pose an equivalent level of concern to persistent, bioaccumulative and toxic (PBT) and very persistent and very bioaccumulative (vPvB) substances under REACH
Get PDFUnder the EU chemicals regulation REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals EC 1907/2006), registrants are not obliged to provide information related to intrinsic substance properties for substances that pose a threat to the drinking water resources. In 2019, perfluorobutane sulfonic acid (PFBS) and 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoic acid (HFPO-DA trade name GenX) were demonstrated to have an equivalent level of concern (ELoC) to persistent, bioaccumulative and toxic or very persistent and very bioaccumulative (PBT/vPvB) substances owing to their persistent, mobile and toxic (PMT) substance properties and very persistent and very mobile (vPvM) substance properties, respectively. They were both subsequently identified as substances of very high concern (SVHC) applying Article 57(f ) in REACH. This work follows up on this regulatory decision by presenting a science based, conceptual level comparison that all PMT/vPvM substances pose an ELoC to PBT/ vPvB substances. Using the two cases named above, as well as 1,4-dioxane, 16 categories were developed to evaluate a) serious effects on human health, b) serious effects on the environment and c) additional effects. 1,4-dioxane has recently been proposed to be classified as Carcinogenic 1B by the Committee for Risk Assessment (RAC). The aim was to enable an objective and scientifically justified conclusion that these classes of substances have an equivalent level of concern for the environment and human health.publishedVersio
Site-specific soil reaction model for monopiles in soft clay based on laboratory element stress-strain curves
Get PDFLarge-diameter monopiles are the predominant foundation solution for supporting offshore wind turbines. They are conventionally designed using soil reaction curves developed for long slender piles used for supporting offshore oil and gas platforms (e.g., the API p-y model). However, due to the difference in the length/diameter ratio and the resulting soil mechanisms, the use of p-y curves alone can lead to significant under-prediction of the lateral stiffness and capacity of monopiles. To overcome the shortcoming, the authors have previously proposed a conceptual two-spring framework, i.e., the so-called ‘p-y + MR-θR’ model, to capture the monopile response in soft clay under lateral loading. The framework uses distributed p-y springs to consider the lateral soil resistance along the pile above the rotation point (RP) and a single moment-rotation (MR-θR) spring attached at the RP to capture the entire soil resistance below the RP, i.e., the distributed resistance along the pile, base shear and base moment at the pile tip. The proposed p-y and MR-θR springs were curve-fitted to the results of 3D numerical analyses. However, as the stress-strain response and the shear strength profile inevitably influence the p-y and MR-θR springs, the applicability of the empirical formulations to soil conditions other than those examined is uncertain. This study proposes an enhancement to the ‘p-y + MR-θR’ framework, in which the p-y and MR-θR springs are not tied to a specific soil and strength profile but fundamentally linked to the properties that can be measured directly in the site investigation and laboratory. This extension is achieved through analytical analyses and an extensive parametric numerical study. The predictive capabilities of the model are demonstrated by backanalyses of finite element analyses and centrifuge model tests. The proposed model provides practising engineers with a simple yet powerful approach to use site-specific soil reaction curves in the design of monopiles embedded in soft clay.publishedVersio
Biochar for the Improvement of Soil and Rock With Acid Potentia
Get PDFBiochar is a carbonaceous material generated by the heating of organic matter under limited access to oxygen (called pyrolysis). While pyrolysis is applied to dry feed, hydrothermal carbonization can be used for wet materials such as sludge. Application of biochar to soil is considered inherent climate friendly since biochar remain stable in the soil for a long time, and thus removing carbon from the short-term carbon cycle. Biochar has the ability to adsorb trace elements and raise pH, when added to soil or/and water. Geomaterials, both soil and rock, containing sulphur in the form of sulphide minerals have the potential to harm the environment. Lowering groundwater in sulphide rich soils and disposal of excavated sulphide rich soil and rock in piles are example of situations where measures have to be taken to mitigate the formation of acid leachate. This presentation aims at presenting the results from two studies where biochar’s capacity to adsorb trace elements is investigated. In the first study, the adsorption capacity of several biochars was compared with leachate generated from the oxidation of sulphide soil, showing a significant decrease of the concentration of elements such as copper and zinc. In the second study, the ability of waste timber biochar to stabilize the leaching from sulphide rich gneisses containing readily soluble, oxidized secondary mineral crusts was investigated. Preliminary results show that the acidity of the oxidized gneisses exceeds the buffer capacity of the biochars, resulting in an acidic, metal rich leachate. Rather reducing metal leaching through sorption and pH control, metals from the biochar matrix are released, resulting in an increased release of metals compared to the control.publishedVersio
Living Labs—A Concept for Co-Designing Nature-Base Solutions
Get PDFLiving Labs are recognized as a progressive form to foster innovation and the strengthening of collaborative planning. The concept has received strong attention by the European Union (EU) research and innovation agendas recently. This contribution investigates how a Living Lab approach could be used for the design and implementation of Nature-Based Solutions (NBS). NBS are gaining acceptance as a more sustainable solution for reducing the exposure to natural hazards and vulnerability to events, such as increased flooding in changing climate. However, a lack of collaborative approaches hinders their broader implementation. A literature review on the theoretical aspects of the Living Labs concept in the context of NBS is conducted, and we compare the theoretical findings with practices that were observed by case studies implementing NBS in a collaborative manner. The Isar-Plan River Restoration in Munich, Germany, and the Mountain Forest Initiative (Bergwaldoffensive). Both of the case studies have already started well before the concept of Living Labs gained wider popularity. Both award-winning cases are recognized good practice for their exemplary in-depth stakeholder involvement. The paper discusses the concepts and approaches of Living Labs and reflects on how it can serve and support in-depth participatory stakeholder involvement.publishedVersio
Monitoring snow avalanches in Grasdalen using an infrasound array
Get PDFThe absence of near real-time information about the avalanche activity is a significant challenge for local avalanche forecasting (Schweizer and van Herwijnen 2013). Information about avalanche activity in neighboring paths (“indicator avalanches”) can be critical in understanding the current snow-stability conditions and for evaluating past bulletins (Kristensen 2016). Reliable systems for automatic monitoring of avalanche activity that can supplement visual observations are desirable for event verification and as input for operational forecasting. An infrasound detection of avalanches (IDA) array was maintained in Grasdalen between October 2014 and spring 2019 (Humstad et al. 2016). IDA system is based on technology developed by iTem and Laboratorio di Geofisica Sperimentale of the University of Florence, Italy (Ulivieri et al. 2012). The system is commercialized in Norway by Wyssen Norge AS, which is a subsidiary of Wyssen Avalanche Control AG in Switzerland. The project has been run as a collaboration between the Norwegian Public Roads Administration (NPRA), Wyssen, and NGI.Norges vassdrags- og energidirektora
The presence, emission and partitioning behavior of polychlorinated biphenyls in waste, leachate and aerosols from Norwegian waste-handling facilities
Get PDFEven though production and open use of polychlorinated biphenyls (PCBs) have been phased out in Western industrialised countries since the 1980s, PCBs were still present in waste collected from different waste handling facilities in Norway in 2013. Sums of seven indicator-PCBs (I-PCB7: PCB-28, -52, -101, -118, -138, -153 and -180) were highest in plastic waste (3700 ±1800 μg/kg, n=15), waste electrical and electronic equipment (WEEE) (1300 ± 400 μg/kg, n=12) and fine vehicle fluff (1800 ± 1400 μg/kg, n=4) and lowest in glass waste, combustibles, bottom ash and fly ash (0.3 to 65 μg/kg). Concentrations in leachate water varied from 1.7 to 2900 ng/L, with higher concentrations found at vehicle and WEEE handling facilities. Particles in leachate water exhibited similar PCB sorption properties as solid waste collected on site, with waste-water partitioning coefficients ranging from 105 to 107. I-PCB7 in air samples collected at the sites were mostly in the gas phase (100–24000 pg/m3), compared to those associated with particles (9–1900 pg/m3). In contrast brominated flame retardants (BFRs) in the same samples were predominantly found associated with particles (e.g. sum of 10 brominated diethyl ethers, ΣBDE10, associated with particles 77–194,000 pg/m3) compared to the gas phase (ΣBDE10 6–473 pg/m3). Measured gas-phase I-PCB7 concentrations are less than predicted, assuming waste-air partitioning in equilibrium with predominant waste on site. However, the gas-particle partitioning behavior of PCBs and BFRs could be predicted using an established partitioning model for ambient aerosols. PCB emissions from Norwegian waste handling facilities occurred primarily in the form of atmospheric vapor or leachate particles.publishedVersio
Throw variations and strain partitioning associated with fault-bend folding along normal faults
Get PDFNormal faults have irregular geometries on a range of scales arising from different processes including refraction and segmentation. A fault with constant dip and displacement on a large-scale will have irregular geometries on smaller scales, the presence of which will generate fault-related folds and down-fault variations in throw. A quantitative model is presented which illustrates the deformation arising from movement on irregular fault surfaces, with fault-bend folding generating geometries reminiscent of normal and reverse drag. Calculations based on the model highlight how fault throws are partitioned between continuous (i.e. folding) and discontinuous (i.e. discrete offset) strain along fault bends for the full range of possible fault dip changes. These calculations illustrate the potential significance of strain partitioning on measured fault throw and the potential errors that will arise if account is not taken of the continuous strains accommodated by folding and bed rotations. We show that fault throw can be subject to errors of up to ca. 50 % for realistic down-dip fault bend geometries (up to ca. 40∘), on otherwise sub-planar faults with constant displacement. This effect will provide irregular variations in throw and bed geometries that must be accounted for in associated kinematic interpretations.publishedVersio
Considerations on scaling behavior in avalanche flow: Implementation in a simple mass block model
Get PDFObservations of runout distances combined with velocity measurements suggest that “major” dry-mixed avalanches show a scale invariance to the total drop height HSC. This is in accordance to the proposed upper-limit envelope of the maximum velocity by McClung and Schaerer (2006). The observations are also supported by a simple scaling analysis using a simple mass block model on cycloidal and parabolic tracks (Gauer, 2018b), concluding Umax~ gHSC/2 . In this supplementary paper, a simple mass block model is presented that includes basic observations of major dry-mixed avalanches, such as mass entrainment and deposition, and that reflects this scale invariance. Almost all model parameters can principally be observed in the field. Model results are compared with a series of avalanche observations of runout and velocity and match well, considering that the model is a first order approximation.publishedVersio
Layering in shales controls microfracturing at the onset of primary migration in source rocks
Get PDFThe process of primary migration, which controls the transfer of hydrocarbons from source to reservoir rocks, necessitates the existence of fluid pathways in low permeability sedimentary formations. Primary migration starts with the maturation of organic matter that produces fluids which increase the effective stress locally. The interactions between local fluid production, microfracturing, stress conditions, and transport remain difficult to apprehend in shale source rocks. Here, we analyze these interactions using a coupled hydro‐mechanical numerical model based on the discrete element method. The model is used to simulate the effects of fluid production emanating from kerogen patches contained within a shale rock alternating kerogen‐poor and kerogen‐rich layers. We identify two microfracturing mechanisms that control fluid migration: i) propagation of hydraulically driven fractures induced by kerogen maturation in kerogen‐rich layers, and ii) compression induced fracturing in kerogen‐poor layers caused by fluid overpressurization of the surrounding kerogen‐rich layers. The relative importance of these two mechanisms is discussed considering different elastic properties contrasts between the shale layers, as well as various stress conditions encountered in sedimentary basins, from normal to reverse faulting regimes. The layering in shales causes local stress redistribution that controls the prevalence of each mechanism over the other and the onset of microfracturing during kerogen maturation. Results are applied to the Draupne formation, a major source rock in the Norwegian continental shelf in the North Sea.publishedVersio
Facilitating microplastic quantification through the introduction of a cellulose dissolution step prior to oxidation: Proof-of-concept and demonstration using diverse samples from the Inner Oslofjord, Norway
Get PDFIdentifying and quantifying microplastic in marine samples can be facilitated by removing natural organic matter (NOM). Cellulosic material, like chitin, however, are a type of NOM that is resistant to chemical digestion, and difficult to eliminate from samples. To address this a two-step digestion method was developed to remove or reduce cellulosic materials in diverse marine media to assist microplastic quantification. This method was applied to reference microplastics, reference cellulosic materials, and diverse marine samples from the Inner Oslofjord Norway. This included plankton, seabed sediments near a water treatment plant and driftline sand. The method was developed and tested for plastic particles >45 μm. The first-step was to pre-dissolve cellulosic materials using a mixture of urea:thiourea:NaOH. This was followed by an oxidative digestion using H2O2 and NaOH. Most reference plastics were unaffected, except minor effects for PET and nylon. After sufficient repetitions, cellulosic materials in both reference and marine samples were largely removed. This method was compared to other digestion methods used for microplastic quantification, including single-step oxidation, alkaline treatment, acid treatment and enzymatic treatment. The results indicate that the pre-dissolution step greatly facilitates NOM and cellulose digestion for the purpose of microplastic quantification in marine samples.publishedVersio