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Projecten - prof.dr. AA (Bart) Koelmans

The main objective of the research is to:

Assess the risks of micro- and nanoplastic for the freshwater and marine environment, by means of monitoring the abundance of plastic in the environment, by assessing the fate, exposure and effect of plastic and associated chemicals on the species and community level, and by developing mechanistic models that can assist in the risk assessment.

  • This research is performed in close collaboration with IMARES.
  • Click HERE for the press release on our new research program 'Technologies for the Risk Assessment of MicroPlastic (TRAMP)', funded by STW. 
  • Click HERE for the latest news and the latest results of our research on microplastic and nanoplastic.

Content of the research:

  • We will develop methods to detect and quantify microplastic in water, sediments and biota and apply these methods to assess the occurrence of plastic in the environment and in biota (Publication).
  • We will perform fate and fate modeling studies. This includes experimental studies of biofouling, aggregation and sedimentation of nano- and microplastic (i.e. as marine snow), modeling the role of bioturbation and filtration by filter feeders on sedimentation-resuspension of microplastic, detailed modeling of nano- and microplastic transport in rivers, multi-media modeling of nanoplastic, and modeling vertical oceanic gradients of plastic abundance.
  • We will perform bioassays to assess dose-response relationships and effect thresholds for aquatic species, in order to obtain species sensitivity distributions (SSD) for microplastics. The resulting community level effect thresholds will be validated against in situ community effect studies, including studies of recolonization at sites impacted by microplastic.
  • We will perform plastic bioaccumulation studies with single species as well as communities representing food webs, using in- and outdoor cosms of various scales. We will use clean as well as contaminated plastics in order to be able to assess the role of plastic ingestion or bioaccumulation in the bioaccumulation of plastic-associated chemicals (Publication).
  • We will develop a plastic-inclusive bioaccumulation model that is able to simulate the effects of plastic on the bioaccumulation of plastic-associated chemicals by including plastic as part of the diet (Publication).
  • We will combine the information on fate and effects from our studies into a risk assessment, which is meant to support the international policy development with respect to microplastic and nanoplastic in the environment.

The main objective of the research is:

To develop spatially and temporally explicit fate and water quality models for NPs, to perform scenario studies to mechanistically understand the system model behavior and improve the NP exposure assessment in the aquatic environment, and to provide guidance for the risk assessment for NPs.

Content of the research

  • We will develop calculation routines for aggregation-sedimentation that can translate the fundamental aggregation behavior of colloids and nanosized particles to the scale of water systems. The algorithms will be validated against detailed Smoluchowsky-type models describing aggregation, and will be parameterized using experimental data from aggregation-sedimentation experiments using NPs, natural colloids and sediments in natural waters (Publication).
  • We will adapt and develop water quality models in order to link emissions, transport and fate to water quality. Emissions to aquatic systems will be parameterized, using a scenario-based approach and information of releases, including uncertainty. In this way it is possible to model the impact of emission reduction measures and to study the (non)-linearity of the model-output with respect to emissions (Publication).
  • The model will be evaluated against NP concentrations in the river Dommel. To measure NP concentrations in the river, a sampling campaign will be performed and various metal-based NP concentrations will be measured using spICP-MS (Publication).
  • The data will be used to assess the effects of river and lake morphometry on NP retention in rivers and lakes, and to assess the implications of the presence of carbon-based NPs on the fate, retention, bioavailability and risks of NP-associated chemicals (Trojan horse effect) (Publication).
  • The findings will be used to provide guidance on a tiered risk assessment scheme for NPs in the aquatic environment (Publication).


Various remediation techniques are being applied in order to reduce risk associated with POPs in sediments. These techniques often are expensive, ineffective and damaging for benthic communities residing in the sediment. In our previous work we showed that naturally occurring carbonaceous materials, like black carbon, strongly limit the bioavailability of organic contaminants in sediments, which limits the bioaccumulation of these chemicals. Consequently, the addition of activated carbon to sediments can efficiently adsorb hydrophobic PAH and PCB and reduce contaminant concentrations in the pore water and in the tissue of aquatic and terrestrial organisms.

The objective of this research line is to:

Develop safe, validated and cost effective remediation techniques with activated carbon application either as a protective barrier for benthic organisms in sediments or as a cleaning material based on sediment type, contamination level and site characteristics.

Content of the research

  • In order to implement in-situ or ex-situ remediation processes, we will first study the timescales of contaminant adsorption and desorption to and from activated carbon in several sediment remediation scenarios, as well as the effects of activated carbon addition on contaminant bioavailability and bioaccumulation (Publication).
  • We will model  the effects of activated carbon amendments on the fate of PCB and PAH in the food web, i.e. benthic organisms, zooplankton, macrophytes and fish. These models can be used to perform a priori scenario calculations and therefore constitute an important tool in the design stage of a remediation effort (Publication).
  • In order to assess the ecological safety of adding activated carbon to sediments, effect studies will be performed. We will apply a novel bioassay setup that allows for the battery testing of the effect of activated carbon on a suite of benthic species, and assess and model effects on the community and ecosystem level (Publication).
  • Population models will be developed that quantify the trade-off between the advantageous effects of reducing the toxicity of POPs and the negative effects of activated carbon on benthic habitats (Publication).
  • Outdoor mesocosm experiments and full field scale sediment remediation experiments will be performed in order to demonstrate the safety and the potential of the new technologies (Publication).
  • The novel remediation technologies will be compared and evaluated against other current remediation strategies, based on effectiveness, complexity and cost (Publication).


More information (in Dutch) On the STW Website

Projecten van AA Koelmans op de Narcis database.