Presentation by Frans Buschman, Deltares, at the Delft3D - User Days (Day 4: Water quality and ecology), during Delft Software Days - Edition 2019. Thursday, 14 November 2019, Delft.

1. Plastic transport in rivers:
what is below the water surface?
Frans Buschman
Delft3D User Days 2019
14 November 2019

2. Contents
1. Problem of mismanaged plastic waste
2. Project aiming to develop a standardized monitoring strategy for
microplastics in the Netherlands
• From conceptual model to effect chain model
• Modelling distribution
3. Paper on Riverine plastic emission from Jakarta into the ocean (Indonesia)

3. Plastic rivers
Citarum river (Indonesia) and canal in India

4. An example from Haiti
• Drainage channel or waste
dump:
• Plastic waiting to be transported
to the river
• Land reclamation!

5. Polymer types, densities and sizes
Polymer type Density
(tonnes/m3)
PS-E 0.06
PUR 0.85
PP 0.91
PE-LD 0.92
PE-HD 0.94
PS 1.06
PA 1.14
PET 1.37
PVC 1.45
SBR 1.65
nano
micro
macro

6. Important processes river-coastal zone-ocean
Lebreton, L. et al. Global mass budget for positively buoyant macroplastic debris in ocean.
Nature Communications 9, 12922 (2019).

7. Scenarios of plastic transport towards the ocean
• In 2050 5 times
more plastic
produced than
in 2015
• Why?
• Cheap
• Light
• highly
resistant !

8. Sources, pathways, receptors

9. Threat for animals and ecosystems
Photo: J.A. Van Franeker, IMARES
Macroplastics:
• Wounding
• Suffocation
• Starvation
Microplastics:
• Accumulation in
food chain
Effect on humans?

10. Project aim: to develop a standardized monitoring strategy
• In collaboration with Rijkswaterstaat
• Aim: Develop an applicable and standardized monitoring strategy for
microplastic distribution in fresh water bodies
• Optimization and standardization of sampling and analysis
• Development of a distribution model for Rhine and Meuse
• To select monitoring locations
• To extrapolate (costly and scarce) observations
Frans Buschman, Myra van der Meulen, Arjen Markus, Marc Weeber en Frank Kleissen (2018) Roadmap voor de
modellering van verspreiding microplastics in Rijkswateren, Deltares report 11202218-003-ZKS-0002

11. From conceptual model to effect chain
Which factors are relevant for the distribution of microplastics
in rivers, estuaries, canals and lakes?
Nutrients
Waves/ Flow
Light
Temp.
SPM
Algea
Bed
Plankton
Benthos
Fish
Fish at bed
Concentration
microplastics
Density MPs
Shellfish
Bio-Fouling
Atmospheric deposition
Size MPs
Microbes
Salt concentration
Plastic type MPs
Discharge
Roughness shoreMacroplastics
Obstacles
Nanoplastics
Point sources
Non-point sources
Detritivorous
Non-Indigenous Species
Human health
Birds

12. Effect chain for microplastics in a River
Suspended
sediment
(mg/l)
Tide
Flow
Turbulence
Waves
Hetero-
Aggregation
Concentration
Microplastics
watercolumn
(g/m3)
MP mobile sediment
layer
(g/m3)
Deposition Resuspension
MP immobile
sediment layer
(g/m3)
Bioturbation and
disturbance
Reservoir MP in
biota (g/indiv)
Supply of microplastics
from point and non-point
sources
Ingestion-
Excretion
Release after mortalitySediment transport
(horizontal)
Advection
Resuspension
sediment
Density MP +
Suspended
Sediment
(kg/m3)
De- aggregation
Concentration
macroplastics
(g/m3)
Fragmen
-tation
Riparian
vegetation
(roughness/
collection surface)
Importance
process
Uncertainty
including current
knowledge level
Legend

13. Effect of wind in Noordzeekanaal around Amsterdam

14. Method for first rough simulation
1. Estimate the concentration of microplastics from 17
observations
1. Lobith: 0.56 mg/m3
2. Eijsden: 0.14 mg /m3
2. Use results of 2014 national flow model (LSM)
3. Modelling processes for 24 types of microplastics:
1. Advection
2. Aggregation (homo and hetero)
3. Deposition
4. Estimate pathways of microplastics from border to sea
Annelotte van der Linden, Arjen Markus en Frans Buschman (2019) Riverine transport of microplastics from the Dutch
border to the North sea, Deltares report 11203712-002-ZKS-0004

15. Results
• Around 80% transported to sea
• Deposition occurs in Haringvliet
A B

16. Paper: Riverine MACROplastic emission from Jakarta
• Aims of submitted paper (The Ocean Cleanup and Deltares):
• Estimate macroplastic emission from rivers and canals that run through
the city of Jakarta into the sea
• Demonstrate how simple measurements, empirical relations and
hydrodynamic model output can be used to estimate plastic transport
across time and space
Van Emmerik, Loozen, van Oeveren, Buschman and Prinsen (2019) Riverine plastic emission from Jakarta into the
ocean, ERL-084033.

17. Method: monitoring
• Visual counting from bridges
(van Emmerik et al. 2018)
• Trawling from bridges to
sample debris to determine:
• plastic composition
• variation of plastic
transport within the water
column
• ratio between plastic and
non-plastic waste
van Emmerik, Tim, et al. "A Methodology to Characterize Riverine Macroplastic Emission into the
Ocean." Frontiers in Marine Science 5 (2018): 372.

18. Method: monitoring and modelling
• Plastic content of the sampled
debris was found to be between
37% and 54%
• Numbers counted → plastic mass
• Surface → cross section
• Rainfall runoff model to
• Obtain discharge in monitoring
period
• Obtain discharge in whole year

19. Results of floating plastics
Variation in width in time

20. Discussion and conclusion
• Observations carried out in May:
end of wet season
• Assuming the same plastic
concentration throughout year
• Total plastic transport towards
ocean is 2100 tonnes/year
• = 3% of the mismanaged plastic
waste
• Half is transported in
Ciliwung river

21. To conclude
• Transport of plastics in rivers is likely to
increase, at least globally.
• Do we know the main transport
processes?
• Is the large majority of plastics
transported in the top layer of the water
column?
• How much micro- and macroplastic is
accumulated in deposition areas like
Haringvliet?
• With this knowledge plastic removal can
be optimized.

22. Questions?