Abstract:
Airborne microplastics (AMPs) have been found in our atmosphere, and they have
currently received significant global attention since they can enter the human body
through inhalation, dermal contact, or ingestion and may pose a serious potential threat
to human life in the future. This study was carried out based on an open dumpsite and
a plastic crusher plant located in Kanadola, Sri Lanka, which have a high potential
as a source for anthropogenic microplastic contamination in the air. Lichen samples
were collected by using stratified random sampling, and this area was divided into
three zones based on the distance from the plastic crusher plant; a close contact zone
(50 m), an intermediate zone (50-100 m), and a remote zone (100-200 m). Background
control samples were collected from the Kumbalgama area. Lichen samples were digested
with acid digestion, and visual inspection of microplastics was carried out using a
stereomicroscope. Identification of microplastics was performed using a hot needle test.
The total number of AMPs per 1 gram of dry weight of lichen in each sampling zone
was statistically analyzed using one-way ANOVA (95% confidence interval) to compare
sampling zones. The results showed that each sampling zone has statistically significant
difference (P > 0.05), and a post hoc test using the Tukey test revealed that the
close contact zone, remote area, and control zone have statistically significant difference
(P > 0.05), but the close contact zone and intermediate zone do not (P > 0.05). Overall,
it was found that the lichens can be used as a bioindicator and passive depositional
sampler for qualitative and quantitative analysis of AMPs.
