Breakdown and Modification of Microplastic Beads by Aeolian Abrasion

Saltation is an important
wind erosion process that can cause the
modification and breakdown of particles by aeolian abrasion. It is
recognized that microplastic particles can be transported by wind,
but the effect of saltation on microplastic properties is unknown.
This study examined the impact of simulated saltation alongside quartz
grains on the size, shape, and surface properties of spherical microplastic
beads. The diameter of the microplastics was reduced by 30–50%
over 240–300 h of abrasion with a mass loss of c. 80%. For abrasion periods up to 200 h, the microplastic beads remained
spherical with minimal change to overall shape. Over 95% of the fragments
of plastic removed from the surface of the microbeads during the abrasion
process had a diameter of ≤10 μm. In addition, during
the abrasion process, fine particles derived from breakdown of the
quartz grains became attached to the surfaces of the microbeads resulting
in a reduction in carbon and an increase in silicon detected on the
particle surface. The results suggest that microplastics may be mechanically
broken down during aeolian saltation and small fragments produced
have the potential for long distance transport as well as being within
the size range for human respiration.