In:
Biogeosciences, Copernicus GmbH, Vol. 18, No. 1 ( 2021-01-11), p. 159-167
Abstract:
Abstract. The breakdown of soil aggregates and the extraction of
particulate organic matter (POM) by ultrasonication and density
fractionation is a method widely used in soil organic matter (SOM) analyses.
It has recently also been used for the extraction of microplastic from soil
samples. However, the investigation of POM physiochemical properties and
ecological functions might be biased if particles are comminuted during the
treatment. In this work, different types of POM, which are representative
of different terrestrial ecosystems and anthropogenic influences, were
tested for their structural stability in the face of ultrasonication in the range
of 0 to 500 J mL−1. The occluded particulate organic matter (oPOM)
of an agricultural and forest soil as well as pyrochar showed a significant
reduction of particle size at ≥50 J mL−1 by an average factor
of 1.37±0.16 and a concurrent reduction of recovery rates by an
average of 21.7±10.7 % when being extracted. Our results imply
that increasing ultrasonication causes increasing retention of POM within
the sedimenting phase, leading to a misinterpretation of certain POM
fractions as more strongly bound oPOM or part of the mineral-associated
organic matter (MOM). This could, for example, lead to a false estimation of physical
stabilization. In contrast, neither fresh nor weathered polyethylene (PE),
polyethylene terephthalate (PET) and polybutylene adipate terephthalate
(PBAT) microplastics showed a reduction of particle size or the recovery
rate after application of ultrasound. We conclude that ultrasonication
applied to soils has no impact on microplastic size distribution and thus
provides a valuable tool for the assessment of microplastics in soils and
soil aggregates.
Type of Medium:
Online Resource
ISSN:
1726-4189
DOI:
10.5194/bg-18-159-2021
DOI:
10.5194/bg-18-159-2021-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2021
detail.hit.zdb_id:
2158181-2
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