Student researchers from city NGO detect microplastics in salt samples

Bengaluru: A group of high school students, guided by the city-based NGO Prayoga Institute of Education Research, tested salt quality in Bengaluru after learning of the Great Pacific Garbage Patch.

A five-month study found microplastics in four out of seven salt samples tested.

The team collected seven varieties of commercially available salt — sea salt, rock salt and pink salt — from Bengaluru markets. Each sample was tested for microplastics using polarised microscopy.

“Four out of seven samples showed microplastic contamination through microscopic characterisation, confirmed chemically by Fourier Transform Infrared Spectroscopy. Plastics detected included polyethylene, polyvinyl chloride (PVC) and polyethylene terephthalate (PET), all widely used in packaging,” the research revealed.

Some samples also had high levels of total solids and fine nylon fibres, researchers said.

"Microplastics enter the human body in multiple ways and salt is one of them because it is sourced from the marine where microplastics are prevalent. Researchers at Prayoga trained students to identify microplastics using their unique birefringence property, which enabled clear and unambiguous detection in salt,” said Prayoga director research and principal investigator KS Nagabhushana.

Plastic waste dumped into water bodies and seas breaks down into microplastics. These particles remain suspended in seawater and enter salt during evaporation. Fibres from textiles and industrial units discarded into oceans also reach the human body through salt.

"Our study on microplastics in salt addressed a universal plastic pollution problem. As society fails to curb pollution, the issue worsens daily. The fact that plastic is entering our bodies and affecting health is alarming. I also gained a deeper understanding of food processing,” said Anuradha Dileep, a student researcher.

Relentless dumping of plastics led to the Great Pacific Garbage Patch, a vast accumulation of marine debris estimated at 1.8 trillion pieces of plastic.

The research was part of Anveshana, Prayoga’s research-led flagship programme. It was supervised by Prayoga director research and principal investigator KS Nagabhushana and co-principal investigator Padmapriya, who guided four class 9 students: Varsha Vinay (NPS, Rajajinagar), Anarghya H Sastry (Goldenbee Global School), and Anuradha Dileep and Shreya Bharadwaj (Samvida).