A study, which sampled top global brands, has found that more than 90 per cent of bottled water is contaminated with microplastics.
Researchers from the State University of New York in the US tested 259 individual bottles from 27 different lots across 11 brands sold in 9 countries.
Samples from 19 locations, including New Delhi, Chennai, and Mumbai in India, were analysed.
After accounting for possible laboratory contamination, 93 per cent of bottled water showed some sign of microplastic contamination.
Researchers found an average of 10.4 microplastic particles per liter of bottled water using spectroscopic analysis.
This is twice as much as what was found in previous study on tap water, they said.
The data from the report states that the contamination is at least partially coming from the packaging or the bottling process itself.
With the rise in plastics manufacture, there has been an associated rise in plastic pollution of the external environment.
Recently, plastic pollution has been found within freshwater lakes, inland seas, rivers, wetlands and organisms from plankton to whales.
For the study, sample lots were procured with an eye to geographic diversity, size of the national packaged drinking water market (China, USA, Brazil, India, Indonesia, Mexico), and high per captia consumption of packaged drinking water (Lebanon, Mexico, Thailand, USA).
Leading international brands in this study included Aquafina, Dasani, Evian, Nestle Pure Life, and San Pellegrino.
Leading national brands included Aqua (Indonesia), Bisleri (India), Epura (Mexico), Gerolsteiner (Germany), Minalba (Brazil), and Wahaha (China).
As many bottled water brands are simply filtered municipal tap water, sample lots were purchased from a number of locations to increase the likelihood of diverse bottling sources.
Retail purchase, package preparation, and acceptance by shipping office of most sample cases were documented with video and still photography to confirm chain of possession, researchers said in the report.
For those samples with 500-600 ml per bottle, 10 bottles were randomly chosen from the lot, while for the 750 ml samples, 6 bottles were chosen, and for the 2L sample, 4 bottles were randomly chosen for analysis.
Only seventeen bottles out of the 259 bottles analysed showed no microplastics contamination, indicating that 93 per cent of the bottled water tested showed some sign of contamination.
The densities of microplastics contamination were quite variable ranging from the 17 bottles with no contamination to one bottle that showed an excess of 10,000 microplastic particles per liter.
A sample of Bisleri bottled water from Chennai showed over 5,000 microplastic particles per liter.
Polypropylene, often used to make plastic bottle caps, was found to be the most common polymeric material (54 per cent), while Nylon was the second most abundant (16 per cent).
Polyethylene corresponded to 10 per cent of the particles analysed.
“This study was as a follow-up to a tap water study released in September 2017. We found roughly twice as many plastic particles within bottled water as compared to tap water on average,” according to the report.