A recent study jointly conducted by researchers from the Central University of Kerala (CUK) and the Manipal Institute of Technology has found a drastic increase in the presence of microplastics in the soil in Kasaragod town post the COVID-19 pandemic.
The study was conducted as part of a research project sanctioned by the Kerala State Council for Science, Technology and Environment (KSCSTE). It is significant as microplastics released from products such as face masks pose a serious threat to environment while their ecotoxicological impacts are unknown.
K. Sandeep, Assistant Professor, department of Geology at CUK, and one of the researchers, explained that plastic debris could be in all shapes and sizes. But those that are less than five millimetres in length are called microplastics, and they can harm soil, water, and life. Microplastics can affect soil properties, and organisms and microbes in the soil, besides entering the plant body and adversely impacting its growth.
Face masks are seen discarded indiscriminately in Kasaragod town. Their disintegration owing to sunlight and combustion could release microplastic fibres into the soil, he said.
Microplastics in soil predominantly have polypropylene and high-density polyethylene (HDPE) compositions. Although packaging materials and cloth fibres can also contribute to generation of microplastics, a two-fold increase in their presence in the soil post-pandemic indicates a significant contribution from face masks.
According to Dr. Sandeep, soil at parks, schools, railway station, offices, beaches, bus terminal, and restaurants in Kasaragod town from October 2019 to March 2021 was examined as part of the study.
The highest presence of microplastics was found at the railway station and bus terminal. However, there was only a slight increase during the period owing to the lockdown. Even beach areas documented low microplastic abundance. However, the remaining places showed more than two-fold increase in microplastic concentration in the soil, he said.
“We found an average abundance of 515 particles/kg in 2019, which increased to 960 particles/kg in 2021. Flakes, fibres, and films are the most abundant types documented in the soil of Kasaragod,” said Dr. Sandeep.
He added that though blue-coloured microplastics were abundant in 2019, the presence of red microplastics was high in 2021. The consequences of microplastic contamination needed to be explored in detail as little was known about microplastics and their impacts, he said.
When it comes to physical and chemical properties of soil, microplastics can increase soil porosity, alter its aggregate structure, influence enzymatic activities, and reduce microbial population.
The study also suggested proper disposal and management of plastic materials, including surgical face masks and PPE kits, in the region.
The study has been published in the scientific journal Marine Pollution Bulletin in its April issue. Besides Dr. Sandeep, faculty members who were part of the study were Dr. Sijinkumar A.V. (CUK), Dr. Anish Warrier (Manipal Institute of Technology), and students Reethu, Aravind, Rafaz, and Biswajit.
Published - April 11, 2023 08:19 pm IST
