The next time you pick up a supermarket or ATM receipt, you might also be handling chemicals that could quietly harm your health. Recent research by three school students — R. Usha (Grade 10, Sai Krushna Vidya Mandir School, Hosadoddi Village, Bengaluru), Aniketh V. Bhat (Grade 10, Rashtrotthana Vidya Kendra, Banashankari, Bengaluru), and R. Nalini (Grade 9, Sai Krushna Vidya Mandir School, Hosadoddi Village, Bengaluru) — has brought this alarming truth to light.
Carried out at the Prayoga Institute of Education Research under the Anveshana student research program, the project was guided by Principal Investigator Dr. Athavan Anand and Co-PI Asha C. H. The study confirmed the presence of toxic chemicals such as Bisphenol S (BPS) and Diphenyl Sulfone (DPS) in thermal paper — the kind used to print receipts in stores, bus stops, toll booths, and ATMs. Millions handle such receipts daily, often unaware of the potential health risks.
What Makes Bisphenol S Dangerous?
Bisphenol S (BPS) is commonly used as a replacement for Bisphenol A (BPA), a chemical phased out due to its endocrine-disrupting properties and links to multiple health disorders. However, emerging global research shows that BPS may cause similar harm.
When thermal printers generate heat, BPS reacts with the dye to form visible text on paper. Because the chemical is not permanently bonded to the paper, it easily transfers to the skin and enters the body upon touch. Once absorbed, it can linger for hours, potentially affecting the heart, hormones, and nervous system, and may even increase cancer risk.
Uncovering the Chemicals: How the Study Was Done
To identify harmful compounds, the students tested both printed and unprinted thermal papers using various solvents. They purchased unprinted thermal paper from a Bengaluru stationery store and cut it into uniform 1×1 cm squares. Printed bills were collected from ATMs, supermarkets, bus stations, and local vendors for comparison.
Using solvents like hexane, petroleum ether, ethanol, chloroform, ethyl acetate, methanol, and water, they extracted chemicals and analyzed them with thin-layer chromatography (TLC) to identify the widest extraction range. From 5 grams of thermal paper samples, they compared the chemical composition of printed and unprinted papers.
As per the press release, the analysis confirmed the presence of BPS and, unexpectedly, DPS, another toxic compound.
Testing Toxicity: From Lab to Living Organisms
To understand the biological impact of these chemicals, the team used SwissADME, a computational software that predicts how substances behave inside the body — including solubility, cell permeability, and blood-brain barrier penetration.
They also tested toxicity using Daphnia pulex (water fleas), tiny aquatic organisms sensitive to environmental changes. The results were striking — the fleas’ heart rate dropped significantly, and higher chemical concentrations caused death within 24 hours. These findings point to serious potential health risks from prolonged or repeated exposure, especially for people who handle receipts daily, such as cashiers and bus conductors.
Exploring Safer Alternatives
According to Dr. S. Athavan Alias Anand, Senior Researcher – Chemistry and Principal Investigator of the project, switching to digital receipts via email or SMS is a simple, eco-friendly way to minimize exposure. He added that Prayoga plans to expand the research to assess other everyday products for hidden chemical risks and explore sustainable substitutes for thermal paper.
One promising innovation is the use of vitamin C–based ink, already implemented in institutions like Yale University Library (USA). Such developments point toward a healthier, environmentally responsible future for everyday transactions.
Students Speak: Learning Beyond the Classroom
Reflecting on her experience, R. Usha, a Grade 10 student researcher, said,
“Before this project, I never imagined that simple shop receipts could be harmful. Discovering chemicals like BPA in thermal papers made me more aware of what we handle daily. This project helped me think critically about everyday items and made me proud that our research can spread awareness.”
Dr. Athavan added,
“The students’ dedication was remarkable. From learning extraction techniques to understanding public health implications, they displayed genuine curiosity and responsibility. Their work shows how school-level research can inspire social and scientific awareness.”
A Step Toward Science, Awareness, and Change
This project reflects Prayoga’s mission to empower school students — including those from disadvantaged backgrounds — to conduct authentic, high-quality research addressing real-world problems. By combining scientific learning with social responsibility, the initiative aims to inspire a generation of young researchers to create awareness, promote policy change, and champion safer, healthier alternatives in everyday life.