The world’s first spatiotemporally accurate model for simulating behaviour and of engineered nanoparticles in surface waters has been created by researchers of Wageningen University.
Nanotechnology is developing fast. Emissions of less than 100 nm engineered nanoparticles (ENPs) are also growing as a result.
Measuring ENP levls in the environment is very challenging, so exposure evaluations have to fall back on modelling. Previous models could only predict average background concentrations on a continental or national scale.
Wageningen researcher Bart Koelmans said:
The new NanoDUFLOW model, as it is called, is able to simulate the concentrations of ENPs, and their homo- and heteroaggregates in space and time, for any hydrological flow regime of a river.
Inside NanoDUFLOW is an algorhythm that calculates all related interactions among 35 kinds of particles including ENPs. The code decides upon aggregation, settling or prolonged flow in the river.
The rate of interactions depends on the flow conditions in the river, which are calculated in the hydrology module of NanoDUFLOW. This module can be set to match the channel structure of any catchment as defined by the user, enabling a high degree flexibility.
ENPs are an emergent class of chemicals with unique properties. That means some new process descriptions needed to be developed.
One of the main parameters in this new type of models is the attachment efficiency. Attachment efficiency is the chance that two particles stay together when they collide, a chance that depends on the nature of the colliding particles and the chemistry of the water.
Smart calculation methods had to be developed, which enabled the estimation of the attachment efficiency from laboratory experiments with ENPs and natural particles and waters collected in the field.
Joris T.K. Quik, Jeroen J.M. de Klein, Albert A. Koelmans Spatially explicit fate modelling of nanomaterials in natural waters Water Research Volume 80, 1 September 2015, Pages 200–208 doi:10.1016/j.watres.2015.05.025
Illustration: Wageningen University