Plastic particles found in
bottled water
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.
Companies
whose brands were tested told the BBC that their bottling plants were operated
to the highest standards.
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.
Commenting
on the results, Prof Mason said: "It's not catastrophic, the numbers that
we're seeing, but it is concerning."
Experts have
told the BBC that people in developing countries where tap water may be
polluted should continue to drink water from plastic bottles.
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:
§ Aquafina
§ Dasani
§ Evian
§ Nestle Pure Life
§ San Pellegrino
Leading national brands
included:
§ Aqua (Indonesia)
§ Bisleri (India)
§ Epura (Mexico)
§ Gerolsteiner (Germany)
§ Minalba (Brazil)
§ Wahaha (China)
§ 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.
§ Some of
these particles – large enough to be handled individually - were then analysed
by infrared spectroscopy, confirmed as plastic and further identified as
particular types of polymer.
§ 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 surprise
to researchers was the wide variety of findings – 17 of the 259 bottles tested
showed no evidence of plastic but all of the rest did, with big differences
even within brands.
§ 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.
§ Nestle told us its own internal testing for microplastics began
more than two years ago and had not detected any "above trace level".
A spokesman added that Prof Mason’s study missed key steps to avoid "false
positives" but he invited Orb Media to compare methods.
§ Gerolsteiner also said it had been testing its water for microplastics
for a number of years and that the results showed levels "significantly
below the limits for particles" set for pharmaceutical companies. It said
it could not understand how Prof Mason’s study reached its conclusions.
§ It also said
its measures exceeded industry standards but added that microparticles are
"everywhere" so "the possibility of them entering the product
from ambient air or packaging materials during the bottling process can
therefore not be completely ruled out".
§ Coca-Cola said it had some of the most stringent quality standards
in the industry and used a "multi-step filtration process". But it
too acknowledged that microplastics "appear to be ubiquitous and therefore
may be found at minute levels even in highly treated products".
§ Danone said it could not comment on the study because "the
methodology used is unclear" but added that its own bottles had "food
grade packaging".
§ It pointed
out that there are no regulations on microplastics or a scientific consensus on
how to test for them, and it also highlighted a much smaller German study last
year that found plastic particles in single use bottles but not above a
statistically significant amount.
§ PepsiCo said Aquafina had "rigorous quality control measures
sanitary manufacturing practices, filtration and other food safety mechanisms
which yield a reliably safe product".
§ It described
the science of microplastics as "an emerging field, in its infancy, which
requires further scientific analysis, peer-reviewed research and greater
collaboration across many stakeholders".
§ The full Orb
Media report can be found at www.OrbMedia.org
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