Plastic pollution in the oceans has reached a stage where microplastics - pieces smaller than 5mm - now outnumber stars in our galaxy, according to UN secretary general António Guterres.
And by 2050, he says, if present trends continue, there will be more plastic in the world's oceans than fish.
People in the drought-stricken Western Cape, Cape Town in particular, have been forced to focus on the quantity of water as supplies declined drastically, but environmentalists say it is just as important to focus on the quality of water. Curbing plastic pollution is one way ordinary people can help improve the quality of our water.
Because of the huge amount of plastic pollution in the world's seas, lakes and rivers, the UN Environmental Programme (UNEP) has made the theme for this year's World Environment Day on June 5 "Beat Plastic Pollution".
Guterres says no place on Earth is untouched by plastic pollution, including remote spots in the Arctic.
The UN says its message to the global community on World Environment Day is to reject all "single-use" plastic items - those that are thrown away after being used only once. Its slogan is "refuse what you can't re-use".
All over the world people are taking action on June 5 against plastic pollution to highlight the problem, to show how they have reduced their own plastic consumption and to challenge others to do the same.
Locally, some environment activists have formed the Waste Reduction Far South group, and will be visiting restaurants, cafes and shops on the eastern and western seaboards of the Southern Peninsula to assess how businesses are dealing with the problem of single-use plastic.
Businesses will be asked 12 questions in a survey, and the results will be published.
Patrick Dowling of Kommetjie, a member of the group, said the vast amount of plastic pollution in places such as the Little Lotus River and Zandvlei had disturbed many locals, and had led to the group being established.
"This survey is one phase of a sustained plastic reduction campaign, not just a flash in the pan. We really want to turn the tide of plastic pollution," Dowling said.
They will target places that sell take-away food and drink, and ask how these businesses deal with items such as plastic straws and cutlery, packaging for coffee and food, plastic bags and styrofoam.
A 'new' water source
"At the moment the big emphasis with water has been avoiding Day Zero, so everyone is focused on water quantity. But closely aligned is water quality, which means ensuring all water can be used productively, and not polluted," Dowling said.
He said the authorities were looking at using storm water as a "new" water source to recharge aquifers.
"If you look at the plastic that is taken along with the storm water, heaven help us. Can you imagine the systems that will have to be put in place to take out the plastic pollution?"
Dowling said some businesses had already started taking action against single-use plastic. One encouraged customers to bring their own coffee mugs, and gave them free coffee the first time.
Another offered free coffee to anyone bringing a bag of litter before 09:00.
"Plastic plays an important role in the economy, but single-use plastic definitely needs to be phased out," Dowling said.
50% of plastic is single-use
Head of UNEP Erik Solheim writes that there are 51 trillion microplastic particles in the world's oceans, 500 times more than the stars in our galaxy.
They come from plastic items that break up, or are additives in facial scrubs and toothpaste. A single wash of acrylics can release over 700 000 particles.
Solheim says while there is debate and conflicting research, potentially harmful plastic fragments are getting into our bodies in increasing quantities. These can serve as a magnet for other pollutants such as dioxins, metals and pesticides.
But the problem is not plastic itself, he says, but what we do with it.
"We buy one million plastic drinking bottles every minute, and use roughly 500 billion disposable plastic bags every year. Some 50% of plastic is single-use. Nearly one third of plastic packaging escapes collection and clogs the city's [systems]. Thirteen tons of plastic reach our oceans where it smothers coral reefs and threatens wildlife. It can persist up to 1 000 years before it fully disintegrates," Solheim said.
He referred to research by Sherri Mason from the State University of New York who had tested more than 250 bottles of water from eleven global brands and found plastic debris in 93% of them.
Social media campaign
Mason said while the exact implications of humans swallowing microplastic were not known, "we all have a pretty innate understanding that it probably isn't good.
"We have seen the impacts on aquatic species - from dehydration/starvation to the transmission of bio-accumulative toxic compounds - and we shouldn't expect it to be any different for us.
Last month the European Commission proposed banning single-use plastic products such as straws and putting the burden of cleaning up waste on the manufacturers. The proposed ban would also require EU countries to collect 90% of single-use bottles for water and other drinks by 2025, and producers to help cover costs of waste management.
* You can join UNEP's global game of #BeatPlasticPollution by choosing a type of single-use plastic you are ready to give up; take a selfie showing yourself with the re-usable alternative that you are ready to embrace; share your selfie on social media and tag three friends, businesses or high-profile people to challenge them to do the same within 24 hours. Be sure to use the #BeatPlasticPollution hashtag and mention @UNEnvironment.