New research has found that plastic bottled water contains hundreds of thousands of tiny toxic plastic particles.
These findings are likely to come as a shock to those who switch from tap water to bottled water, as they thought it would be better for their health.
Drinking bottled water can mean that your body is contaminated with tiny plastic particles that scientists fear can accumulate in your vital organs and have unknown health effects.
Nanoplastics have been linked to cancer, fertility problems, and birth defects.
Using state-of-the-art laser scanning technology, scientists have found that a liter of water in a bottle contains an average of 240,000 microplastics, compared to only 5.5 per liter of tap water.
Researchers at Columbia University tested three popular brands of bottled water and analyzed the microplastics contained in them using lasers, which were only 100 nanometers in size.
These particles (nanoplastics) are much smaller than the microplastics previously detected in bottled water.
However, these particles are considered potentially toxic because they are so small that they can directly enter blood cells and the brain.
These tiny particles contain phthalates – chemicals that make plastics more durable.
This chemical is known to interfere with the secretion of hormones in the body.
According to the study, they are "linked to developmental, reproductive, brain, immune, and other problems."
The highest estimate was found at 370,000 particles.
Conventional techniques can only detect microplastics from 5 millimeters to 1 micrometer, while nanoplastics, which are one millionth of a meter, or 1/25,000th of an inch, are very difficult to detect. The diameter of nanoplastic microparticles is less than 1 micron.
A breakthrough study in 2018 found that a liter of bottled water contained about 300 microplastic particles, but researchers had limited measurement technology at the time.
Research is currently underway around the world to assess its potential harmful effects.
A new technique called stimulated Raman scattering (SRS) microscopy was used.
This method uses two laser beams to probe the bottle to resonate with a specific molecule, and then determines its source through a computer algorithm.
The results showed that 90% of these molecules were nanoparticles and 10% were microplastics.
One common type of nanoparticle is polyethylene terephthalate (PET).
Co-author of the study, Professor Beizhan Yan, an environmental chemist at Columbia University, said: "This is not surprising because many water bottles are made from this material.
He goes on to say: "PET is also used in bottled sodas, sports drinks and products such as ketchup and mayonnaise.
When the bottle is crushed or heated, the microplastics may fall off and enter the water.
Another microplastic found in water bottles is polyamide – a type of nylon that surpasses PET.
Ironically," Professor Yan said, "this could come from a plastic filter, which is said to be used to purify water before bottling."
Other common plastics include polystyrene, polyvinyl chloride (PVC) and polymethyl methacrylate, which are used in a variety of industrial processes.
However, the researchers found that it was "disturbing" that the named plastics only accounted for about 10% of all nanoparticles found in the samples. They don't know what the rest is.
Wei Min, a biophysicist and co-author of the study, said the study opened up a new field of science, adding: "Before, it was just dark, uncharted territory.
The study of nanoplastics is important because the smaller something is, the easier it is to get into our bodies.
Previous studies have shown that tap water contains microplastics, although the levels are much lower than those of bottled water.
Globally, plastic production continues to pose a threat to the environment – 400 million tonnes of plastic are produced every year.
More than 30 million tonnes of plastic are dumped in water or on land every year, and many products made from plastic, such as synthetic clothing, shed particulates during use.
Experts are still working to determine the impact on human health.