Temporal Archive of Atmospheric Microplastic Deposition Presented in Ombrotrophic Peat

Ombrotrophic peatlandfed
solely from atmospheric deposition
of nutrients and precipitationprovide unique archives of atmospheric
pollution and have been used to illustrate trends and changes in atmospheric
trace element composition from the recent decadal to the Holocene
period. With the acknowledgment of atmosphere plastic pollution, analysis
of ombrotrophic peat presents an opportunity to characterize the historical
atmospheric microplastic pollution prevalence. Ombrotrophic peatland
is often located in comparatively pristine mountainous and boreal
areas, acting as sentinels of environmental change. In this paired
site study, a Sphagnum ombrotrophic peat record is
used for the first time to identify the trend of atmospheric microplastic
pollution. This high altitude, remote location ombrotrophic peat archive
pilot study identifies microplastic presence in the atmospheric pollution
record, increasing from <5(±1) particles/m2/day
in the 1960s to 178(±72) particles/m2/day in 2015–2020
in a trend similar to the European plastic production and waste management.
Compared to this catchment’s lake sediment archive, the ombrotrophic
peat core appears to be effective in collecting and representing atmospheric
microplastic deposition in this remote catchment, collecting microplastic
particles that are predominantly ≤20 μm. This study suggests
that peat records may be a useful tool in assessing the past quantities
and trends of atmospheric microplastic.