Figure 2 Waste plastic in seawater

Not only in the ocean, but also on land, microplastics have been found to have entered the food chain. In April of this year, Mexican scientist Esperanza Verta discovered microplastics in the soil, earthworms, hen feces, and stomach, which can be used for energy decomposition after self incineration and burial of waste plastics, confirming for the first time that microplastics have entered the terrestrial food chain. Recently, a US agency conducted over 150 tap water tests in multiple cities around the world, and the results showed that 83% of tap water contains microplastics, indicating that terrestrial water sources have also been affected by microplastics. There are also reports at home and abroad that microplastics have been detected in products such as table salt, sea salt, beer, and honey. Perhaps the pollution of microplastics is already ubiquitous.

Not only does microplastics pollute the environment, but they also pose a greater threat to biosafety.

The microplastic part comes from plastic products and may release toxic and harmful substances, causing direct harm to the marine environment. The surface of microplastics is also prone to adsorbing heavy metals and persistent organic pollutants in the ocean, such as pesticides, flame retardants, polychlorinated biphenyls, etc., which pose chemical hazards to the ecological environment due to ocean currents. Microplastics are easily engulfed by marine organisms and accumulate within them, posing a threat to the safety of marine organisms. Scientific research has confirmed that microplastic pollution in the ocean has varying degrees of impact on the growth, development, ability to evade natural enemies, and reproduction of marine organisms. In addition, microplastics as carriers may carry foreign species and potential pathogenic bacteria, posing a threat to the stability of marine ecosystems. What is even more worrying is that microplastics can be transmitted through the marine food chain and ultimately enter the human food chain, posing a threat to human health and safety. Although it has not yet been confirmed what exact hazards microplastics pose to human health, similar to PM2.5, it is not ruled out that micro and nano sized microplastic particles may enter the human circulatory system. If microplastics are ingested for a long time, it may also cause some chemicals to accumulate in the human body, which is clearly not conducive to human health. Of course, this is only a speculation, and further in-depth research is needed on the impact of microplastics on ecology and human health.

Figure 3 Polluted beaches and dead fish

Faced with the proliferation of microplastics in the ocean, countries around the world are actively taking action to strengthen monitoring and prevention.

Microplastics and low nutrient marine organisms, such as plankton, have similar sizes and densities. Most marine organisms cannot distinguish between prey and plastic particles during predation, so microplastics are easily ingested by marine organisms. In nature, over 220 species including protozoa, planktonic animals, fish, turtles, birds, whales, etc. have been found to consume microplastics during their diet. Some fish, such as bass, particularly enjoy swallowing plastic particles during their infancy. Their love for microplastics even exceeds their food, plankton, and they eat plastic instead of food.

Figure 4 Polluted beaches and dead fish

Later, many marine organisms were caught again and entered the public's dining table, forming a biological chain of geese. As a result, plastic pollution caused by humans has spread throughout every corner of the earth. Human beings have made plastic, used plastic, discarded plastic, and finally plastic may return to the human body through microplastics, which is a kind of irony!

China is the world's largest producer and consumer of plastics, and microplastic pollution also poses a serious threat to China's marine ecosystem. However, research on microplastics in China started relatively late, and related monitoring technologies are not yet complete. Currently, the public has insufficient understanding of microplastics and their hazards. However, the Chinese government has attached great importance to microplastic pollution and taken action. Since 2007, China has started routine monitoring of marine waste, including plastic waste. Since 2016, China has been monitoring offshore microplastics, and this year, for the first time, microplastics monitoring has been implemented in the Arctic and East Pacific.

Microplastics, as an emerging source of pollution in the ocean and even the global environment, although insignificant or even traceless, are unknowingly changing the marine and global ecological environment, causing huge harm to the environment and affecting the safety and diversity of organisms, ultimately posing a great threat to human health. It's time to face up to the dangers of microplastics! We also hope that all sectors of society can work together to vigorously promote garbage classification, reduce the entry of plastic waste into nature, curb the spread of microplastics, and maintain a beautiful home for marine life, including humanity itself.