Plastic in bottled water: 240,000 cancer-causing nanoplastics found in average bottle of water - how does tap water compare?

Plastic bottles of water contain hundreds of thousands of cancer-causing nanoplastics, damning new research has found. Scientists using the most advanced laser scanning techniques found an average of 240,000 plastic particles in a one-litre bottle of water, compared to 5.5 per one liter of tap water.

Nanoplastics have already been linked to cancer, fertility problems and birth defects. The particles are much smaller than the microplastics previously detected in bottled water however they are considered potentially toxic as they are so small they can directly enter blood cells and the brain.

The microscopic particles carry phthalates - chemicals that make plastics more durable, flexible, and lasting longer. Exposure to phthalates is attributed to 100,000 premature deaths in the US each year. 

Groundbreaking research in 2018 found around 300 microplastic particles in a litre of bottled water. But at that time researchers were limited by their measurement techniques.

Now, with the latest technology, a team used a new technique called Stimulated Raman Scattering (SRS) microscopy to reveal what is in our bottled water. The method probes bottles with two lasers tuned to make specific molecules resonate and a computer algorithm determines their origin.

The results showed that nanoparticles made up 90 per cent of these molecules, and 10 per cent were microplastics. One common type of nanoparticle found was polyethylene terephthalate or PET. Study co-author Professor Beizhan Yan, an environmental chemist at Columbia, said: “PET is also used for bottled sodas, sports drinks, and products such as ketchup and mayonnaise. It probably gets into the water as bits slough off when the bottle is squeezed or gets exposed to heat.”

Another plastic particle found in bottles of water, which outnumbered PET, was polyamide – a type of nylon. Professor Yan said: “Ironically, this probably comes from plastic filters used to supposedly purify the water before it is bottled.”

The other common plastics found included polystyrene, polyvinyl chloride (PVC), and polymethyl methacrylate,. However, the researchers found that these named plastics only accounted for around 10 per cent of all the nanoparticles found in the samples - and they have no idea what the rest are.

The team plans to investigate tap water, which has previously been shown to contain microplastics although in far smaller quantities than bottled water. The study comes as plastic production continues to pose a threat to the environment with more than 30 million tonnes dumped yearly in water or on land. 

Last month researchers from Duke University School of Medicine found nanoplastics affect a specific protein found in the brain that causes changes linked to Parkinson’s disease and other types of dementia. Another study published in April 2023 also discovered that nanoplastic consumption led to reduced cognition and short-term memory in mice.