Plastics in the Ocean - Modelling and risk assessment
- 13:00 Multimedia modeling of nano- and microplastics in the environment
Authors: Bart Koelmans ( Wageningen University ); Joris Quik ( RIVM ); Joris Meesters ( RIVM ); Anja Verschoor ( RIVM )
Understanding plastic flows in the environment is crucial if we are to design methods for risk assessment and mitigation of plastic pollution. Screening level multi-media models have been shown to be helpful for the environmental assessment of nano- and microplastics (NMP) but they are not generally available. Here, we present SimpleBox4Plastics (SB4P) as the first model of this type, assess its validity, and evaluate it by performing rigorous sensitivity analysis. SB4P expresses NMP transport and concentrations in and across air, rain, surface waters, soil, and sediment, accounting for particle-specific processes such as aggregation settling and attachment, including those for nanoscale particles. The model solves simultaneous mass balance equations (MBE) using simple matrix algebra. The MBEs link all concentrations and transfer processes using first-order rate constants for all processes known to be relevant for NMPs. The first-order rate constants are obtained from the literature. The model accounts for emissions to air, soil, water and atmosphere such as those from direct sources, thermal cutting of polymers, 3D printing, and abrasion and wear of plastic items including car tyres. The output of SB4P is mass concentrations of NMPs as free particles, heteroaggregates with natural colloids, and larger natural particles in each compartment in time and at steady state (Figure 1). We evaluate the uncertainty in predicted environmental concentrations (PECs) by performing Monte Carlo (MC) simulations on the environmental fate, concentrations and speciation of NMP with sizes ranging from 100 nm and 10 mm. Realistic distributions of uncertainty and variability were applied for all of SB4N's input and model parameter values. We argue that this allows for the detection of the dominant processes driving fate and distribtion of NMPs as a function of size and polymer type. Finally, SB4P predicted environmental concentrations are useful as background concentrations in environmental risk assessment.
- 13:15 Distribution and fate of microplastic in the marine environment: Can we predict the hotspots?
Authors: Marte Haave ( NORCE ); Helge Avlesen ( NORCE )
Microplastic (MP) is a group of persistent, anthropogenic substances of growing global concern, because of potentially harmful effects. We need to know relevant MP concentrations and effect thresholds to do relevant risk assessmensts, yet environmental MP concentrations are largely unknown. Urban harbors are expected to be highly contaminated by microplastics from anthropogenic activities, wastewater and run-off. Quantification of MP is costly and time-consuming, and prediction of MP hotspots before sampling is thus desirable. MP in was exctracted from sediment at potential MP deposition sites in Byfjorden outside Bergen, using ZnCl2 density separation in a Microplastic Sediment Separator. Particles (>11 µm) were identified spectroscopically using µFTIR imaging and ATR FTIR. Twenty different polymer types were identified, at concentrations from 12 000 to 200 000 particles kg-1 dw. The highest concentrations were found at the discharge site and at the urban site with the finest sediment and the highest organic content. Information about grain size and organic content is often known from mandatory monitoring of chemical and biological status in coastal recipients, and may thus be used as a guide for MP sampling. High resolution 3D numerical ocean models can reproduce the major circulation patterns, and coupled with models for particle transport and sedimentation, can predict hot-spots for MP. Results from monitoring programs like the one here performed are also highly valuable for validation of models. Microplastics comes in a large variety of shapes, sizes and densities, but the numerical experiments with a small set of particle sizes and settling velocities done in this pilot project indicate sedimentation hot-spots in accordance with observations. Input from the MP analyses such as here performed provide feedback to validate the models, leading to more targeted sampling and better mapping of concentration ranges.
This study is the first to report concentration ranges of the MP in a Norwegian fjord to sizes below visual identification. As over 95% of the particles are smaller than 100 µm, this size class is of importance to fully understand MP distribution. MP > 500 µm did not follow the same pattern of distribution as small MP (11-500 m). Reporting as MP concentration per size class will be a useful tool for comparison of MP concentrations in future investigations.
Extraction and purification of particles by Uni Research, Bergen. ATR-FTIR and FT-IR imaging performed at the Biologische Anstalt Helgoland of the Alfred Wegener Institute. Funding by RFFV and Bergen Kommune.
- 13:30 Predictive mapping to identify coastal litter hotspots and optimalise cleanup efforts in remote areas
Authors: Marthe Larsen Haarr ( Salt Lofoten AS ); Joan Fabres ( GRID-Arendal ); Levi Westerveld ( GRID-Arendal ); Sverre Håpnes ( Salt Lofoten AS ); Kjersti Eline Tønnessen Busch ( Salt Lofoten AS )
Coastal cleanup actions are an effective measure to reducing marine litter with few negative environmental impacts. Given the frequent deposition and resuspension of litter along the coast, cleanup actions here can also reduce the pollution in nearby waters. Optimising coastal cleanup actions, however, requires considerable local knowledge on where accumulation hotspots are located. In remote areas, such as the Arctic, such knowledge may be geographically limited. The ability to remotely assess or predict litter accumulation patterns is therefore highly valuable. However, such efforts are often costly and challenging in terms of data and computation needs. SALT and GRID-Arendal have therefore developed a parsimonious approach based on readily available GIS and weather data: a model predicting litter accumulation patterns based on coastline characteristics affecting the potential for deposition, and indicators of litter input based on proximity to key litter sources. Because of the relatively simple data inputs, the model can be used in almost any area at relatively low cost once sufficient ground truthing has taken place. The model parameters are based on rigorous and extensive field work in Lofoten and Vesterålen (Norway), followed by field validation to test the accuracy of model predictions. Thus, the model differs from many other predictive approaches in that it is solidly backed by field data on litter distribution. Work is currently underway to improve model calibration and determine its generalisability to new regions. The model will be a highly useful tool for optimising coastal cleanup actions in the Arctic.
- 13:45 Risk assessment of microplastics in the ocean
Authors: Gert Everaert ( Flanders Marine Institute (VLIZ) ); Lisbeth Van Cauwenberghe ( Ghent University ); Maarten De Rijcke ( Flanders Marine Institute (VLIZ) ); Albert A. Koelmans ( Wageningen University ); Jan Mees ( Flanders Marine Institute (VLIZ) ); Michiel Vandegehuchte ( Flanders Marine Institute (VLIZ) ); Colin R. Janssen ( Ghent University )
The presence of microplastics in the marine environment has been an issue of concern for over a decade now, but their environmental risk in the ocean have, to date, not been addressed and quantified. The environmental risk assessment of microplastics presented here quantifies, based on a regulatory framework for assessing environmental risks of pollutants (i.e. REACH), safe concentrations for the marine pelagic and marine benthic compartment. Above these safe concentrations adverse biological effects are likely to occur. At most locations, the in situ concentrations in the upper pelagic compartment remain below the safe concentration (6650 particles m-3). However, local exceedances of this threshold are already taking place in sites that are heavily polluted with buoyant microplastics. In addition to the pelagic phase, also inshore, harbour and beach sediments are of concern. As human populations continue to grow, and if our dependence on plastic does not change under a business as usual approach, we may expect a steady and substantial increase in microplastic concentrations in both the pelagic and benthic marine environment. Adverse effects of microplastics are to be expected on highly polluted beaches and in coastal ecosystems as of the second half of this century if plastics emissions are not reduced.
- 14:00 Quantifying Ecological Risks of Aquatic Micro- and Nanoplastic
Authors: Ellen Besseling ( Wageningen University ); Paula Redondo-Hasselerharm ( Wageningen University ); Edwin Foekema ( Wageningen Marine Research ); Albert Koelmans ( Wageningen University )
In the laboratory, diverse effects of nano- and microplastic (NMP) have been demonstrated once NMP doses exceeded effect thresholds. Here we provide an overview of current knowledge on occurrence and such effect thresholds data as regard to microplastics in the aquatic environment. Using this information, we perform one of the first quantitative risk assessments for NMP, while fully accounting for the diversity of the material. The assessment is based on the reviewed data and was done following six steps: (1) assessing ranges of exposure concentrations that are currently found in the aquatic environment globally, (2) refining the expected exposure by use of exposure models, (3) assessing the nano- and microplastic effect thresholds reported to date, (4) assessing community level effect thresholds using a species sensitivity distribution (SSD) approach, (5) reflecting on the latest insights with respect to the effect of micro- and nanoplastic on chemical transfer and risk, and (6) comparison of exposure and effect levels to characterise risk. For the latter, HC5 effect thresholds from the ‘all inclusive’ SSDs were compared with the highest environmental concentrations reported. SSDs were constructed for microplastic or ‘plastic debris’ as a mixture of different sizes and types of particles, which implies that the observed distribution of the stress responses reflects this variability. Furthermore, a pragmatic criterion for combining different endpoints was used, that is, by combining those endpoints that all imply harm at the population level of a species. Hence, the endpoints of survival, reproduction and growth, the latter including any reduction in weight, length or hampering of moulting (while a subsequent effect of these endpoints on reproduction can be expected too), were included. HC5 values show wide confidence intervals and exposure remains far below effect thresholds for most locations, however they suggest that sensitive aquatic organisms in near-shore surface waters might presently be at risk.
- 14:15 Mapping marine litter in the Norwegian and Russian Arctic Seas -MALINOR-
Authors: Lionel Camus ( Akvaplan-niva ); Alexei Bambulyak ( Akvaplan-niva ); Claudia Halsband ( Akvaplan-niva ); Frank Beuchel ( Akvaplan-niva ); Peygham Ghaffari Nooran ( Akvaplan-niva ); Trude Borch ( Akvaplan-niva ); Perrine Gerraudie ( Akvaplan-niva ); Jannike Falk Andersson ( SALT Lofoten ); Torbjorn Houge ( Maritime Robotics ); Paul Renaud ( UNIS ); Dorthe Herzke ( NILU ); Denis Moiseev ( Murmansk Marine Biological Institute ); Alexander Korsenko ( Zubov State Oceanographic Institute of Roshydromet ); Oleg Sutkaytis ( WWF Russia ); Maria Gavrilo ( Association Maritime Heritage ); Joan Fabres ( Grid Arendal ); Johannes Rohr ( Met.no )
While plastic appeared to be a great invention as described by the French philosopher Roland Barthes in Mythologies (1957) who used the term "a plasticized world" for the benefit of all, today the enthusiasm for plastic would certainly not be the same anymore. 8.3 billion tons of plastic have been produced between 1950 to 2015 of which some ends up in the sea generating the so-called "marine litter" which does poorly degrade, accumulate on the sea floor and on the shoreline causing major visual impact but also sever harm to marine life throughout the ecological chain. Marine litter are also present and increasing in the Arctic. While some mapping and characterization has been done, major gaps of knowledge to understand where the litter is distributed throughout the Norwegian, Barents, Kara Seas and the high Arctic and what its characteristics and sources are remain unexplored. From this foregoing account, the Norwegian Research Council is financing the MALINOR project (2019-2021) with the objective to map areas of marine litter and describe its characteristics in the Arctic in collaboration with Russian institutions with a multi-disciplinary approach. We will extract data from the scientific & grey literature on the distribution of litter in the Norwegian Russian Arctic, identify ongoing activities on this topic both in Norway and Russia, build up a joint Norwegian Russian database, perform mapping using multidisciplinary approaches (robotics, digital solutions, GIS, satellite pictures), Collect offshore data using research cruises of opportunity, develop a predictive tool for litter distribution, and, importantly disseminate the findings to the students, public and policy makers both nationally in Norway and Russia and also internationally (EU, UNEP, Arctic Council). Through such a project, we believe that thorough science along with professional communication to kids, education of students and delivering high quality information to policy makers, the enthusiasm may come back – this is time to solve the plastic litter problem in the Arctic!
Thursday 24th January 2019
13:00 - 14:30