Microplastics: A hidden danger

According to the UN, there will be more plastic than fish in the world's oceans by 2050. Research conducted in 2014 by the 5 Gyres Institute, a nonprofit dedicated to the elimination of plastic waste, said that from 2007 to 2013, some 5.25 trillion plastic particles were floating in the oceans, weighing about 269,000 metric tons.

A 2016 report by the UN showed that about 800 marine and coastal species were found to have been affected by plastic garbage entanglement or inhalation, and microplastics have been detected in about 40 percent of cetaceans and 44 percent of seabird species.

The garbage could find its way onto our dinner tables through the food chain or sea salt, the UN said.

According to the UN Food and Agriculture Organization in 2017, humans are likely to consume 7 micrograms of microplastics with every 225 grams of shellfish.

Sea salt in the United Kingdom, France and Spain, China and the United States has also been found to contain microplastics, according to The Guardian in 2017.

Shi Huahong, professor of environmental science at East China Normal University, said that to date, there is still no strong evidence to show that microplastics can cause obvious damage to the ecosystem.

"The natural environment is complex and full of various kinds of pollutants and other environmental impact factors, so it is difficult to relate negative effects on creatures to specific pollution factors," he said.

"However, large numbers of laboratory tests have proved that creatures exposed to a certain amount of microplastics in the lab can have various toxicological reactions."

China has introduced a national campaign aimed at curbing microplastics pollution in the oceans.

In 2016, the density of marine microplastics was introduced as a routine monitoring item for the marine environment, and results are regularly posted on the official website of the Ministry of Ecology and Environment.

Also, by November, 237 cities at prefectural level or above had adopted waste-sorting programs after a nationwide campaign started in June.

"This will help to recycle plastic and prevent waste from flowing into the oceans," Huo said.