Experts cautioned that the extent of the risk to human health posed by such contamination remains unclear.
"There are connections to increases in certain kinds of cancer to lower sperm count to increases in conditions like ADHD and autism," said Mason.
"We know that they are connected to these synthetic chemicals in the environment and we know that plastics are providing kind of a means to get those chemicals into our bodies."
- Time to ditch plastic? . . .
However, representatives from the bottled water industry took issue with the findings, saying they were not peer-reviewed and "not based on sound science," according to a statement from the International Bottled Water Association.
"A recent scientific study published in the peer-reviewed journal Water Research in February 2018 concluded that no statistically relevant amount of microplastic can be found in water in single-use plastic bottles," it added.
"There is no scientific consensus on the potential health impacts of microplastic particles. The data on the topic is limited and conclusions differ dramatically from one study to another."
Jacqueline Savitz, chief policy officer for North America at Oceana, a marine advocacy group that was not involved in the research, said the study provides more evidence that society must abandon the ubiquitous use of plastic water bottles.