Bottled water, marketed as being a pure and cleaner alternative to normal drinking water, is not as clean as it is advertised to be. They have been found to contain microplastic and other particles.
Widespread contamination with plastic debris was revealed in exclusive tests run on more than 250 bottles from 11 leading brands, collected from nine countries.
While some bottles had effectively zero plastic, one was found to contain over 10,000 particles per litre, according to the findings of
Orb Media, a non-profit journalism organization based in Washington.
The global average was 325 microplastic particles per litre of bottled water. Plastic was found in 93% of the samples.
However, it is still unclear what effect the microplastic particles have on human health.
The bottle brands tested are Bisleri owned by Bisleri; Dasani of Coca-Cola; Evian, Aqua of Danone; Gerolsteiner of Gerolsteiner; Minalba of Minalba; Nestle Pure life, San Pellegrino of Nestle; Aquafina, E-pura of PepsiCo; Wahaha of Wahaha.
Averaging across lots by brand, Nestle Pure Life and Gerolsteiner showed the highest average densities at 930 and 807 MPP/L, respectively, while San Pellegrino and Minalba showed the lowest microplastic contamination with 30.0 and 63.1 MPP/L, respectively, according to research findings.
The study data indicated that the contamination is at least partially coming from the packaging and or the bottling process itself.
For plastic particles in the 100 micron, or 0.10 millimetre size range, tests conducted for Orb at the State University of New York revealed a global average of 10.4 plastic particles per litre.
These particles were confirmed as plastic using an industry standard infrared microscope. The tests also showed a much greater number of even smaller particles that researchers said were also “likely plastic.” The global average for these particles was 314.6 per litre.
Erik Solheim, executive director of the UN Environment Program, described the finding as shocking.
Bottled water is the fastest-growing beverage market in the world valued at $147 billion per year, according to The Economist, with the output is soon expected to hit 300 billion litres a year.
In 2016, more than 480 billion plastic drinking water bottles were sold. By 2021, the sale is expected to hit 583.3 billion, The Guardian reported last year.
The popularity of bottled water has scientists and governments increasingly concerned about the effects of microplastic pollution. Recent studies have found microplastics – particles smaller than 5mm – in the oceans, soil, air, lakes, and rivers, Orb said.
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Martin Wagner, a toxicologist at the Norwegian University of Science and Technology, said: “Based on our current knowledge, which is very fragmentary and incomplete, there is little health concern.”
But he noted that the study was a “very illuminative example” highlighting the “intimate contact” between people and plastic.
As much as 90% of microplastic consumed might pass through the gut without incident while a small percentage of the rest 10% – smaller than 150 microns or 0.15mm – may enter kidneys or liver, according to the European Union and the FAO.
Plastic well within that size range was found in the Orb study.
Jane Muncke, managing director at the Food Packaging Forum, a research organization in Zurich, pointed out that all the chemicals in plastics were not known, adding that assumptions about how plastic behaves in the gut are drawn from scientific models, not laboratory studies.
How the study was carried out
Professor Sherri Mason, a leading microplastic researcher at the State University of New York, supervised the study.
Mason’s team infused each bottle with a dye called Nile Red that binds plastic. The water was then filtered to 1.5 microns, or 0.0015 millimetres – smaller than a human red blood cell.
The dyed plastic particles on each filter glowed under the microscope but the concentration varied. While one bottle had a concentration of over 10,000 plastic particles per litre, others contained a mere handful. Some effectively had none.
Mason analyzed bigger particles (0.10 millimetres) using Fourier-Transform infrared spectroscopy that uses laser light to read an object’s molecular signature to identify the plastic.
The most common of these bigger particles was polypropylene, used in bottle caps. Polyethylene terephthalate, used in beverage bottles, was just 6%. Water in glass bottles was also found to contain microplastic.
Andrew Mayes, who developed the Nile Red method for identifying microplastic, said the fluorescing particles that were too small to be analyzed by FTIR should also be called “probable microplastic” as “some of it might be another, unknown, substance to which Nile Red stain is adhering.”
Nestle Head of Quality Frederic de Bruyne noted that Mason’s tests did not include a step in which biological substances are removed from the sample. Without elaborating, he said some of the fluorescing particles could be false positives — natural material that the Nile Red had also stained.
Mason noted that the so-called “digestion step” is used on debris-filled samples from the ocean or the seashore, and was not needed for bottled water. “Certainly they are not suggesting that pure, filtered, pristine water is likely to have wood, algae, or chitin [prawn shells] in it?” she said.
Mayes, a senior lecturer in chemistry at the University of East Anglia, said the count was “pretty substantial.”
“... The numbers reported here are very conservative and likely undercounting, especially with regard to smaller microplastics (<100 micrometres), which were found to be more prominent (on average 95%) as compared to particles greater than 100 micrometres (on average 5%),” the researchers said.
Although different methods were used in Orb's studies of tap water and bottled water, there is room to compare the results. The tested bottled water samples contained nearly twice plastic particles >100 micrometres compared to tap water on average (10.4 vs. 5.45 particles/L).
“If your tap water is of high quality, that's always better,” said Scott Belcher, professor of toxicology at North Carolina State University. “If you have contaminated and unsafe drinking water, bottled water may be your only alternative.”
What the bottlers say
The manufacturers claimed that their products met all government requirements. Two of the leading brands confirmed that their products contained microplastic, but insisted that the Orb’s study significantly overstated the amount.
Gerolsteiner, a German bottler, said its tests “have come up with a significantly lower quantity of microparticles per liter” than found in Orb’s study.
Nestle said it tested six bottles from three locations after an inquiry from Orb. The results showed between zero and five plastic particles per litre, according to Nestle’s de Bruyne.
None of the other bottlers agreed to make results of their tests for plastic contamination public.
“We stand by the safety of our bottled water products,” the American Beverage Association said in a statement, according to Orb.
The US does not have specific rules for microplastic in food and beverages.
Anca Paduraru, a food safety spokeswoman for the European Commission, said that while microplastic is not directly regulated in bottled water, “legislation makes clear there must be no contaminants.”
Mason noted that the so-called “digestion step” is used on debris-filled samples from the ocean or the seashore, and was not needed for bottled water. “Certainly they are not suggesting that pure, filtered, pristine water is likely to have wood, algae, or chitin [prawn shells] in it?” she said.
Mayes, a senior lecturer in chemistry at the University of East Anglia, said the count was “pretty substantial.”
“... The numbers reported here are very conservative and likely undercounting, especially with regard to smaller microplastics (<100 micrometres), which were found to be more prominent (on average 95%) as compared to particles greater than 100 micrometres (on average 5%),” the researchers said.
Although different methods were used in Orb's studies of tap water and bottled water, there is room to compare the results. The tested bottled water samples contained nearly twice plastic particles >100 micrometres compared to tap water on average (10.4 vs. 5.45 particles/L).
“If your tap water is of high quality, that's always better,” said Scott Belcher, professor of toxicology at North Carolina State University. “If you have contaminated and unsafe drinking water, bottled water may be your only alternative.”