Harrison et al nano fase_spatiotemp_thames_setac 2019
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This document summarizes a spatiotemporal model of nanomaterial fate in the environment. The model tracks nanomaterials through soil, water, sediment and biota compartments over large spatial and temporal scales. It models various processes including attachment, bioturbation, aggregation, dissolution and uptake. Model outputs show the distribution of titanium dioxide in different environmental compartments and its predicted environmental concentrations in soil and water over time. The model is useful for validating simpler screening tools and demonstrates the importance of attachment, bioturbation and tidal dynamics on nanomaterial transport and accumulation.
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Harrison et al nano fase_spatiotemp_thames_setac 2019
- 5. Spatiotemporal model of nanomaterial fate, speciation and bio-uptake in the environment Grid cellGrid cellGrid cell Grid cellGrid cellSoil profile Grid cellGrid cellWater body Bed sediment Grid cellGrid cellSoil layer Biota
- 6. Soil layer, 𝑙 = 1 Soil layer, 𝑙 = 2 Soil layer, 𝑙 = 3 precipitation and evapotranspiration percolation free NPs bioturbation attached NPs erosion attached NPs bio-uptake NM sources transformations Examples of processes modelled: Transformations for TiO2: attachment to soil matrix Bioturbation rate is function of earthworm density: 𝑘bioturb,𝑙:𝑙+1 = 𝛽𝑤𝑙 𝑑 Empirical bioturbation parameter Worm density Layer depth Bioturbation rate
- 7. Examples of processes modelled: Transformations for TiO2: heteroaggregation to SPM Reach Reach Bed sediment deposition & resuspension aggregated NM bio-uptake Reach advection NM sourceserosion & runoff aggregated NM advection transformation 𝑘hetero = 𝛼hetero 𝑘coll 𝐶spm Collision frequency Attachment efficiency Heteroaggregation rate SPM particle concentration
- 8. Geography Soil properties Land use [1] doi:10.1016/j.envpol.2018.07.108 [2] doi:10.5194/gmd-10-4145-2017 [3] doi:10.3390/hydrology1010063
- 10. IMPROVE IMAGE Resolution: 5x5 km Year: 2015 Material: TiO2
- 11. Total mass of nano-TiO2 in the entire catchment, split by environmental compartment. With estuary No estuary soil water sediment Modelling tides is important they make sediments act more as a sink Soil acts as a sink
- 12. Nano-TiO2 predicted environmental concentration (PEC) in soil at the end of 2015. Soil NM concentrations Maximum PEC: 2.8 μg/kg soil
- 13. River and estuary NM concentrations Influence of dynamic variables, e.g. hydrological flows, over time. Low flows high concentrations Estuary is big low concentration
- 14. River and estuary NM concentrations Influence of dynamic variables, e.g. hydrological flows, over time. Low flows high concentrations Estuary is big low concentration
- 15. Importance of attachment and bioturbation in soils. Attachment Bioturbation Attachment Bioturbation Attachment Bioturbation
- 16. • Comparing PEC to Predicted No Effect Concentration (PNEC) is an important part of environmental risk assessment. • Screening level tools such as SimpleBox4nano useful for this, but only give “one number” per compartment. • NanoFASE WSO model useful to validate, compare and scope changes to such screening level tools. Towards validating nanomaterial predicted environmental concentrations from SimpleBox4nano using the NanoFASE spatiotemporal multimedia fate model J.T. Quik, S. Harrison, J. Slootweg, J.A. Meesters, V. Adam, J. Kuenen, S. Lofts, W. Peijnenburg Presented at SETAC Helsinki
- 17. • One of the most “whole picture” model of ENMs in existence. • Demonstrates the importance of non-nano and nano- specific processes over large spatial and temporal scales: • Heteroaggregation drives sedimentation • Attachment to soil matrix soil acts as a sink • Bioturbation dominant process that mixes soil • Tidal dynamics estuarine sediments act as a sink • Model outputs can be used to validate screening level models, relevant for chemicals regulation.
- 18. • Different materials with different chemistry, e.g.: • Silver dissolution and sulphidation • Sea model and biotic uptake. • Longer temporal scales, using emissions data for 2000-2021. • Larger and different spatial scales. • Case studies, e.g.: Ag in textiles, Cu applied as fungicide, Cu as antifoulant ship paint. • Continue comparisons with SimpleBox4nano, e.g. comparison of time to steady state. Biota 𝑘elim 𝑘growth Stored fraction, 𝑆𝑓 𝑘uptake
- 19. This project receives funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 646002.