64-13 Microplastics: The Inorganic Non-Mineral Conundrum for Texture

Session: Emerging Voices in Soil and Paleosol Science (Posters)

Presenting Author:

Author:

Abstract:

Texture, which is the relative proportion of different sized particles (sand, silt, and clay) is considered a “master soil property” on the grounds that it exerts a strong influence on nearly all soil properties and processes. Soil texture influences physical, chemical, biological, and hydrological properties such as pore size distribution, water infiltration and percolation rates, depth of clay accumulation, cation exchange capacity, carbon storage, atmospheric gas exchange, and biomass productivity. However, the current definition of texture does not refer to all particles, it specifically refers to mineral particles, which are naturally occurring, inorganic substances that have a distinct chemical composition, and an ordered atomic (crystalline) structure. An inorganic anthropogenic pollutant of concern in sediment and soil is plastic particles. Plastic particles do not have a single defined chemical composition. Instead, they’re a diverse group of materials, concerning their composition and shape. It is currently estimated that the concentration of plastic particles < 5 mm in diameter in soil is 23 times higher than in the oceans and it will continue to increase due to the continued production of petroleum-based plastics, land management practices (plastic mulches), improper waste disposal, and the deposition of plastics in fluvial environments. Current research indicates that plastic particles weaken aggregates, alter the emission patterns of CO₂ and N₂O, decrease the microbial activity within the soil, and decrease soil permeability. This ultimately results in an environment that is more susceptible to erosion. This necessitates a new understanding of soil texture, which could be approached in multiple ways; (1) adjust the current definition of texture to include mineral and non-mineral inorganic particles, (2) modify texture in a similar way as coarse fragments based on the total volumetric percentages of plastic particles, or (3) include gravimetric percentages of sand, silt, and clay sized plastic particles with texture information. This work provides the first known recommendations on including plastic particles within soil texture information.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-11256

© Copyright 2025 The Geological Society of America (GSA), all rights reserved.