Sunway University researchers find microplastics in sea salt

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The increase in news reports of marine wildlife washing up dead on shores due to complications from ingesting plastic, brings to light the severity of plastic consumption, disposal of plastic and garbage, and pollution of our waterways and oceans.

The Great Pacific garbage patch so far is the largest accumulation of ocean plastic in the world. There are smaller accumulations scattered all around the world. If marine life has been affected, are humans at risk?

This is what piqued the interests of senior lecturers, Dr Jane Gew Lai Ti and Dr Yow Yoon Yen of the Department of Biological Sciences, School of Science and Technology at Sunway University. Curious to find out if there is any form of ocean plastic contamination in the country, they opted for the easiest possible source – sea salt.

“Seawater is a natural and easily accessed source of salt. The conventional extraction process of salt from sea water is with evaporation ponds, which are typically located warm climates with low rain fall and where evaporation is high,” explained Dr Gew.

Drs Gew and Yow tested 14 brands of locally produced salt from hypermarkets in various forms ranging from coarse, fine and super fine. Microplastics (< 5 mm in size) contamination in sea salt will be an indicator of sea water pollution.

Running the salt through a chemistry process; the 2 researchers first infused 250 grams of salt in hydrogen peroxide in a 24-hour shaker incubation at 65 degrees Celsius to digest the ocean organic matter. Double distilled water is then added to the solution and left at room temperature for another 24 hours to allow any residue to settle to the bottom of the bottle prior filtration.

According to Dr Yow, “The supernatant of salt solution is then filtered with filter paper, the weight of each filter paper before and after filtration recorded. The harvested pollutants are then viewed under the stereomicroscope, and further characterised with Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis (SEM-EDX). The procedure was replicated at least three times for all the 14 sea salt brands sold in Malaysia.”

Drs Gew and Yow found three common type of microplastics in the salt samples, which are fiber, fragments and micro beads. The result of their findings is that coarse salt contains the most impurities while super fine salt contains the least.

“We propose manufacturers of salt to have a better filtration process or system. Reduce the pore size of the filter cartridge in the filtration system; or increase the filtering of the salt solutions as these could help reduce presence of microplastics in the edible salts during the manufacturing process,” said Dr Gew.

In line with Sunway University’s commitment to the United Nations Sustainable Development Goals (UNSDGs), Dr Gew and Dr Yow hope to bring to light the severity of plastics pollution in the environment.

An advocate for a more sustainable future, Dr Gew advises all to refrain from using single-use plastic. “This will help prevent further microplastics contamination,” she reiterated.

Dr Jane Gew Lai Ti, Programme Leader of the BSc(Hons) Biomedicine is currently working on drug delivery and antimicrobial nanocoating. Concerned with the use of organic solvents in chemical processes, Dr Gew uses only green solvents for chemical synthesis and extractions in her research projects. She is determined to work on projects that are in line with the SDGs.

Dr Yow Yoon Yen who earned her PhD in Algae Biotechnology from the University of Malaya looks forward to discovering how algae play a role in the SDGs.

This research was supported by Sunway University, Malaysia. Special thanks to student helpers who contributed to this project.