Abstract
The perceived impact of soil microplastics on soil aggregation is
primarily attributed to their potential toxicity toward soil
microorganisms. However, only a limited number of studies have
undertaken comprehensive controlled experiments involving sterilized
soils to substantiate this notion. The present study embarked on soil
incubation experiments encompassing both non-sterilized soils and soils
subjected to oven-heating sterilization to investigate the ramifications
of polyethylene (PE) and polypropylene (PP) microplastics, characterized
by mesh sizes of 30, 150, and 1000, on both the water-stability and
mechanical stability of soil aggregates. The presence of microplastics
decreased aggregation stability in Tianjin soils (on average -48.89%
and -81.61% for 0.5-1 and 1-2 mm aggregates, respectively). The impact
of microplastics was notably more evident in the non-sterilized soils.
Microplastics also demonstrated the capacity to modify aggregate
properties such as surface roughness. This study indicates the pivotal
role played by interactions between soil microplastics and
microorganisms on soil aggregation, but microplastics hold the potential
to influence soil aggregation through non-biogenic pathways.