CSIR-NIO researchers recommend diffuse reflection method for better study of microplastics

Panaji: A team of researchers from the CSIR-National Institute of Oceanography (NIO) in Goa has recommended the use of diffuse reflection method to study microplastics, which are harmful to plants and animals, in complex environmental matrices like highly loaded turbid water and sediment.

The method involves reflection of light from a surface where an incident ray is reflected at many angles, a senior member of the team said, adding it is the most effective, easy and non-destructive method for the quantification of smaller-sized microplastics.

Explaining why the study was initiated, the researcher said, "Finding microplastics is challenging in complex environmental matrices and the more challenging task is to standardise a protocol which can be followed by everyone and is easy, cost effective and moreover authentic." The study said research in microplastics is important as plastic pollution is one of the most pressing environmental issues globally.

The NIO is one of the constituent laboratories of the Council of Scientific and Industrial Research (CSIR).

The team's research paper recently published in Europe's leading scientific journal – Elsevier – speaks about development of a methodology for confirmed identification of polymers using the Micro Fourier Transform Infrared (FTIR) spectroscopy method that is followed by scientists.

“A rapid increase in the production of disposable plastic products overwhelms the world's capability to deal with them. Global plastic production has shown a substantial rise over the last few decades, growing from 1.7 million tonnes in the 1950s to 368 million tonnes in 2019, with a mild drop during 2020 (367 million tonnes) as a result of the COVID-19 pandemic,” said the journal.

The researchers have said though the micro FTIR spectroscopy represents an ideal method for the detection of microplastics, this technique lacks a standardised mode to be followed in diverse environmental matrices.

They have now recommended the use of "diffuse reflection method in micro-FTIR to study the microplastics in complex environmental matrices like highly loaded turbid water, sediment, biota and others." The study focused on the optimisation, application, and validation of micro FTIR techniques for the identification of smaller-sized microplastics.

The team worked very hard to standardise a protocol for the identification of small size microplastics, the researchers said.

The present study was undertaken to establish an easy, quick, and effective methodology for the characterisation of microplastics, which are often heavily loaded in various kinds of complex environmental samples (particularly from tropical Asian countries), they said.

“It is highly challenging to deal with such kind of sample analysis, using 100 per cent of the filtered microplastics without any damage or loss of the samples,” the research said.

The team of researchers included Dr Mahua Saha, Chaynika Rathore, Priyansha Gupta, Manish Kumar, Akshata Naik and Prof Jacob de Boer from the Netherlands.