Terrestrial plants as a potential temporary sink of atmospheric microplastics during transport

Abstract

Atmospheric transport is an important pathway by which terrestrial microplastics (MPs, with sizes less than 5 mm) can move long distances to remote areas. However, little is known about the environmental behaviors of atmospheric MPs during movement. To address this issue, deposits of MPs on the leaves of plants were studied in two regions, with abundance ranging from 0.07 n/cm2 (pieces per area of leaves) to 0.19 n/cm2. The attached substances were mainly natural materials, but 28% of the total substances were plastics. There was a similar physical-chemical composition of the attached MPs in the two regions suggesting a similar origin. Leaves, regardless of plant species, can indiscriminately retain atmospheric MPs. About 0.13 trillion pieces of MPs are estimated to be attached to leaf surfaces in the top 11 green countries. Leaves of terrestrial plants could be a temporal sink and a source of MPs pollution to remote areas. This is not fully recognized and merits further study.