New studies by US researchers found that major bottled water brands are contaminated with microplastics and pose a risk, while UK Prime Minister Theresa May vowed to ban plastic cotton buds and straws and criticised Britain's 'throwaway culture' that is killing oceans, which followed UK plans for a deposit return scheme for plastic bottles.

The bottled water study by Orb Media and the State University of New York at Fredonia made headlines in March for reporting that, of 250 water bottles sourced from 11 brands in nine different countries, 93 percent of samples were contaminated with microplastics.

Fox News 28 reported that after testing bottles of Aqua, Aquafina, Bisleri, Dasani, Epura, Evian, Gerolsteiner, Minalba, Nestle Pure Life, San Pellegrino and Wahaha water from India, Indonesia, Kenya, Mexico and the United States, researchers identified 325 particles per liter of water. Some bottles tested featured concentrations up to 10,000 plastic pieces per liter.

However, Fox 28 pointed out that the study has not been subjected to scientific peer review and wasn't published in a journal.

The World Health Organization told BBC News that it will be launching a new investigation to review the potential risks of plastic in drinking water.

"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 - all of these products we consume at a very basic level,” said Sherri Mason, a professor of chemistry at SUNY Fredonia who contributed to the study, told BBC.

Though there is no evidence to date that ingesting microplastics is harmful to the human body, the researchers believe the implications need to be better understood. "It's not catastrophic, the numbers that we're seeing, but it is concerning,” Professor Mason said.

In the UK, Sustain, the alliance for better food and farming, said its members were "delighted" by the plastic deposit-return scheme for bottles, after a long campaign by a coalition of Sustain members.

"Sustain members Keep Britain Tidy, Campaign to Protect Rural England (CPRE), and the Marine Conservation Society have led a campaign to introduce DRS in the UK. Their research showed that it could save councils millions of pounds a year," Sustain said.

Currently, UK consumers go through an estimated 13 billion plastic drinks bottles a year, but more than three billion are incinerated, sent to landfill or left to pollute the streets, countryside, and marine environment.

Scotland announced a plan for a DRS scheme in September, while several supermarkets said they will pilot the scheme.

CPRE campaigned for the introduction of a DRS for 10 years. Their litter programme director, Samantha Harding, said: “What’s significant is that producers will now pay the full costs of their packaging, reducing the burden on the taxpayer and setting a strong precedent for other schemes where the polluter pays.”

Dr. Sue Kinsey, MCS senior pollution policy officer, said the move will significantly reduce plastic pollution. "An average of 72 beverage containers per 100m of beach in England was found in our Great British Beach Clean survey in 2017. This is a win-win situation for consumers, taxpayers and the environment alike."