A team of researchers from Universitas Gadjah Mada in Yogyakarta, Indonesia, recently developed a shocking new technique to make the most of old plastic bags by transforming them into carbon quantum dots, or CQDs -- glowing nanoparticles that can sense invisible pollutants in water.

These CQDs typically rely on expensive or hazardous means to produce, but using the plastic shopping bags we often discard -- after just one use -- overcomes that hurdle. The study, published in the Carbon Research journal, details the modified pyrolysis and hydrothermal treatment that these scientists applied to convert the polyethylene from plastic bag waste into CQDs.

The entire process, according to EurekAlert, takes fewer than 10 hours, and the resulting CQDs "achieved a quantum yield of 10.4% ... and showed remarkable stability under [the] UV light" that causes them to glow under certain conditions. By binding selectively to Fe ions, or ferric ions, in water, the glowing CQDs can highlight metal contamination even at near-imperceptible levels.

As reported by the United Nations, we generate over 400 million metric tons of plastic waste around the world each year, a good half of it from single-use plastics. Per the UNDP, less than 10% of this waste is actually recycled, leaving the majority to pile up in our landfills or disposed of through otherwise improper methods.

When landfills overflow, they release planet-heating gases like methane into our atmosphere, as well as other contaminants into our soil and groundwater -- all of which, one way or another, may wind up in our bodies. Other plastic remnants often end up in our oceans as microplastics, jeopardizing the stability of marine ecosystems.

Meanwhile, putting our plastic waste toward water contamination detection can similarly help ensure the security of our public health. Even in trace amounts, metals like lead, cadmium, and mercury can leach into our waterways and natural resources, posing a range of health concerns, from respiratory and cardiovascular issues to carcinogenic effects when ingested.

"This is sustainability meeting smart science," explained Dr. Indriana Kartini, the study's lead researcher. "We're not just reducing plastic waste -- we're turning it into a tool for public health."

Researchers achieve stunning breakthrough using old plastic bags: 'We're turning it into a tool'