International desk, Mar 15: Tests on major brands of bottled water have found that nearly all of them contained tiny particles of plastic.In the largest investigation of its kind, 250 bottles bought in nine different countries were examined.
Research led by journalism organisation Orb Media discovered an average of 10 plastic particles per litre, each larger than the width of a human hair, reports BBC.
Companies whose brands were tested told the BBC that their bottling plants were operated to the highest standards.
The tests were conducted at the State University of New York in Fredonia.
Sherri Mason, a professor of chemistry at the university, conducted the analysis and told BBC News: “We found [plastic] in bottle after bottle and brand after brand.
“It’s not about pointing fingers at particular brands; it’s really showing that this is everywhere, that plastic has become such a pervasive material in our society, and it’s pervading water – all of these products that we consume at a very basic level.”
Currently, there is no evidence that ingesting very small pieces of plastic (microplastics) can cause harm, but understanding the potential implications is an active area of science.
After filtration, the larger particles – yellow marks – are easy to see. ORB MEDIAAfter filtration, the larger particles – yellow marks – are easy to see. ORB MEDIA
Commenting on the results, Prof Mason said: “It’s not catastrophic, the numbers that we’re seeing, but it is concerning.”
Contacted to comment on the findings, the companies behind the brands have insisted that their products meet the highest standards for safety and quality.
They also point to the absence of any regulations on microplastics and of the lack of standardised methods of testing for them.
Last year, Prof Mason found plastic particles in samples of tap water and other researchers have spotted them in seafood, beer, sea salt and even the air.
This latest work comes amid growing international attention on plastic, fuelled by the BBC’s acclaimed Blue Planet 2 series in which Sir David Attenborough highlighted the threat of plastic waste in our oceans.
The research into bottled water involved buying packs from 11 different global and national brands in countries chosen for their large populations or their relatively high consumption of bottled water. These were:
Leading international brands:
Nestle Pure Life
Leading national brands included:
A dye is used that binds to pieces of plasticA dye is used that binds to pieces of plastic
To eliminate any risk of contamination, purchases in shops and deliveries to courier companies were recorded on video. Some packs in the US were ordered over the internet.
The screening for plastic involved adding a dye called Nile Red to each bottle, a technique recently developed by British scientists for the rapid detection of plastic in seawater.
Previous studies have established how the dye sticks to free-floating pieces of plastic and makes them fluoresce under certain wavelengths of light.
Prof Mason and her colleagues filtered their dyed samples and then counted every piece larger than 100 microns – roughly the diameter of a human hair.
Particles smaller than 100 microns – and down to a size of 6.5 microns – were much more numerous (an average of 314 per litre) and were counted using a technique developed in astronomy for totalling the number of stars in the night sky.
The make-up of these particles was not confirmed but Prof Mason said they can “rationally expected to be plastic”.
This is because although Nile Red dye can bind to substances other than plastic – such as fragments of shell or algae containing lipids – these would be unlikely to be present in bottled water.
Since the study has not been through the usual process of peer review and publication in a scientific journal, the BBC has asked experts in the field to comment.
Dr Andrew Mayes, of the University of East Anglia and one of the pioneers of the Nile Red technique, told us it was “very high quality analytical chemistry” and that the results were “quite conservative”.
Michael Walker, a consultant to the Office of the UK Government Chemist and founder board member of the Food Standards Agency, said the work was “well conducted” and that the use of Nile Red has “a very good pedigree”.
Both of them emphasised that the particles below 100 microns had not been identified as plastic but said that since the alternatives would not be expected in bottled water, they could be described as “probably plastic”.
One obvious question is where this plastic may be coming from. Given the amount of polypropylene, which is used in bottle caps, one theory is that the act of opening a bottle may shed particles inside.
To check that the process of testing was not itself adding plastic to the bottles, Prof Mason ran “blanks” in which the purified water used to clean the glassware and the acetone used to dilute the Nile Red dye were themselves investigated.
Small quantities of plastic were found in them – believed to be from the air – but these were subtracted from the final results.
A few bottles were found to have thousands of particles – the vast majority being the smaller ones that are “probably plastic” – but others from the same pack had virtually none.