bottled water
Photo by Ketut Subiyanto:

A new study conducted by researchers at Columbia and Rutgers Universities found that a litre of bottled water contains around 240,000 nanoplastics. The shocking findings have been published in the journal Proceedings of the National Academy of Sciences.

They used a newly developed laser technology and found that bottled water sold in stores may contain 10 to 100 times more plastic fragments than estimated earlier. These nanoparticles are so small that they cannot be seen under a microscope.

Nanoplastics can pass through the tissues of the digestive tract or lungs into the bloodstream. The researchers found that the water contained seven types of plastics; 90 per cent of these particles were nanoplastics, and the rest were microplastics.

The common plastic particles found in the water were polyamide, polypropylene, polyethylene, polymethyl methacrylate, polyvinyl chloride, polystyrene, and polyethylene terephthalate.

Polyamide, a type of nylon, may have come from plastic filters used to purify water, said the study authors.

One of the most common nanoplastic types found in bottled water was polyethylene terephthalate, or PET. Experts believe it takes half a millennia for the polyethylene terephthalate (PET) that makes up bottles to break down. PET is also used for making plastic milk bottles.

Over the years, extensive studies have been conducted on the presence of microplastics in water. However, for the latest study, the researchers examined nanoplastics. Microplastics are tiny plastic particles up to 5mm in diameter, while nanoplastics are particles less than 1 micrometre. The diameter of a human hair is about 70 micrometres.

The study has raised concerns about the potential impact of nanoplastics on human health. "However, our understanding of nanoplastics is limited by the lack of adequate analytical tools," Beizhan Yan from Columbia University, one of the authors of the study, told Down To Earth.

The big picture:

Plastic is everywhere, and animals both on land and at sea mistakenly consume it, and microscopic particles can be found in the air and oceans.

Several studies have shown that water bodies, air, soil, food, and table salt may contain microplastic or nanoplastic particles. Tyre dust and laundry wastewater are among some of the sources of nanoplastics. These can even be transferred to the offspring of living organisms.

They can cross the blood-brain barrier after intravascular injection and accumulate in the brain, per a study published in the US National Centre for Biotechnology Information. However, scientists have not yet fully understood their adverse impact on human beings since these particles are extremely small and difficult to detect.

The scientists believe that if people continue consuming microplastics at the present rate, there will come a time when the threshold levels will be surpassed. When this happens, harm will not only fall upon the environment but also on humans.