posted on 2023-09-08, 18:12authored byMargherita Barchiesi, Merel Kooi, Albert A. Koelmans
The effects and risks of microplastics correlate with
three-dimensional
(3D) properties, such as the volume and surface area of the biologically
accessible fraction of the diverse particle mixtures as they occur
in nature. However, these 3D parameters are difficult to estimate
because measurement methods for spectroscopic and visible light image
analysis yield data in only two dimensions (2D). The best-existing
2D to 3D conversion models require calibration for each new set of
particles, which is labor-intensive. Here we introduce a new model
that does not require calibration and compare its performance with
existing models, including calibration-based ones. For the evaluation,
we developed a new method in which the volumes of environmentally
relevant microplastic mixtures are estimated in one go instead of
on a cumbersome particle-by-particle basis. With this, the new Barchiesi
model can be seen as the most universal. The new model can be implemented
in software used for the analysis of infrared spectroscopy and visual
light image analysis data and is expected to increase the accuracy
of risk assessments based on particle volumes and surface areas as
toxicologically relevant metrics.