INCA-Microplastics (Integrated Catchment model of MicroPlastics transport) is a mathematical model designed to assess microplastics’ fate and transport in landscapes. The model calculates microplastic concentrations and fluxes in and across soil, stream water and river sediments at the scale of a river catchment.
Simulations produced by the model accounts for the effects of plastic particle physical characteristics (size, shape, and density), weather conditions and river flow variability on the retention of microplastic in soils, their runoff to river water, the transport by the stream (e.g., by physically describing the settling and entrainment processes to and from the sediment bed) and their total discharge at the river mouth.
INCA-Microplastics is typically set to represent specific geographical scenarios and can use historical precipitation data to run realistic simulations. The model has been calibrated in a river catchment in Southern Europe and its predictive performance was successfully assessed against experimental data. A detailed description of the model and information on the parameter calibration and assessment of prediction performance is provided in Norling et al. (2023).
INCA-Microplastics was developed at the Norwegian Institute for Water Research (NIVA) by Luca Nizzetto and Magnus Norling. The interface presented here and the frame to estimate microplastic releases have been developed by François Clayer (NIVA).
By filling in the form below, you can access a demonstration page that offers the possibility of testing and exploring some key features of INCA-Microplastics. If you are interested in a specific and more advanced use of the model, please contact info@ikhapp.org.
More about the INCA-Microplastics tool and how to use it
The interface enables easy and interactive access to some of the model’s key features. Users can explore how previsions of microplastic fate and transport in a catchment can be affected by socioeconomic and climatic variables. Users can easily change the following inputs:
- vary the parameters related to microplastic sources
- select one of three geographic context (tropical, temperate, and boreal catchments) reflecting different climate and seasonality patterns
- feed the model using default historical weather time series or use data downscaled from climate change forecasts.
- Start simulations by clicking the “Run model” button.
- Read outputs online or download a report in pdf format.
INCA-Microplastics considers microplastic inputs through two pathways: soil leaching and release from wastewater effluents. Concentrations of microplastics in soil and wastewater are computed by a script that utilizes information from population density, waste generation rate, fraction of mismanaged waste and treated wastewaters as well as additional user inputs. The interface then automatically loads the generated inputs and executes INCA-Microplastic from the cloud. During each run the model dynamically calculates concentrations of microplastics in soil, stream water and river sediments by integrating their source inputs on soil and streamwater and their fluxes between these environmental compartments. The total discharge of microplastics at the river mouth is also computed. All outputs are calculated with a daily resolution. The model accounts for variability in meteorological conditions and can for example be used to predict the effects of floods on the transport of microplastics through the catchment. In this demonstration version simulations cover 2 full generic years.
INCA-Microplastics can in principle receive information on which type of microplastics an operator is interested in. This can be done by introducing data on ranges of sizes and density for different groups of particles. The model distinguishes between elongated particles (such as fibers) and non-elongated particles that are generically named “fragments”. In the demonstration version of the model provided by IKHAPP, these inputs are set to default and cannot be changed. Three types of particles are considered: low density fragments (spheroidal particles with density of 1.01; size ranging 1–10 µm), high density fragments (with density of 1.3; size ranging 1–10 µm) and fibers (with density of 1.3; size ranging 1–100 µm).
The interface provides a set of charts and a simplified report helping users to easily understand and compare results from subsequent runs of the model (e.g., after one or more parameters have been modified). Each working section will be open for two hours. During this time, results from every last simulation are saved and plotted together with the results of the next run of the model. This facilitates comparisons and qualitative evaluation of the effect of changing the parameters. Outputs are also provided using an adaptive text format that helps users to get an easily comprehensible synthesis. A result report can be downloaded in PDF and CSV format for each run.
The executable version of INCA-Microplastics, the model’s open-source code and general information on the framework used to generate it (MOBIUS (Norling et al. 2021)) can be found in a github repository. A complete description of the model and information on its calibration and validation are provided by Nizzetto et al. (2016), Norling et al. (2023). In the professional version, the model can be set to represent specific catchments, which can be described with a desired level of detail. It enables to run simulation for any desired time span by introducing real meteorological data and any available information on microplastic sources (for example obtained from measurements). Several additional features are available compared to the demonstration version, including the possibility of arbitrarily defining multiple classes of microplastics characterized by desired ranges of size and density, setting rates for microplastics degradation, homo, and hetero aggregation, as well as the formation of biofilms.
In the professional version INCA-Microplastic can provide realistic predictions of microplastic transport and distribution over specific landscapes. This makes it a useful tool to assess ecosystem exposure to microplastic under variable conditions, and to evaluate the impact of pollution control measures on levels of microplastics in a given landscape. If you are interested in a specific and more advanced use of the model, please contact info@ikhapp.org.
Credits
Researchers from the Norwegian Institute for Water Research (NIVA) conceived and coordinated the development of the model across its different versions. This was done in collaboration with colleagues from Oxford University, the Swedish University of Agricultural Sciences and IMDEA-water (Spain).
Researcher François Clayer (NIVA) developed the frame for calculating sources of Microplastics to soil and wastewater. He is also the creator of the interface which is jointly presented by IKHAPP and the GIZ 3RproMar project.
