"Su"?!
It's "eating plastic", not being a vegetarian!
The microplastics in the ocean will be absorbed by marine life, and you will "eat" the microplastics while you feast on delicious seafood. Microplastics on the ground may enter the atmosphere, or they may seep into the ground and migrate to groundwater and surface water, so microplastics can also be "drunk" into the body.
In addition to "eating and drinking", you will also "inhale" plastic from the air!
Let's take a look at a place where human activity has had very little impact on the environment – Newfoundland in Canada. The population density is extremely low (1.4 people per km²) and industrial development is very limited. On September 11, 2021, Hurricane Larry made landfall on the island of Newfoundland. The researchers measured the amount of microplastics during the period of September 9~12. The number of microplastic particles per square meter per day before or after the hurricane passed through the sampling point ranged from 700~3000 grains, while the number of microplastic particles falling per square meter per day was as high as 113 569 (± 29 215) particles per square meter when the hurricane pulled through the sampling area. The actual number may be even higher than that, as the study could not count microplastic particles smaller than 1.2 microns in diameter.
What are microplastics?
The term "microplastics" appeared 20 years ago when it was coined by marine scientist Richard Thompson at the University of Plymouth in the United Kingdom. In 2004, he found a lot of plastic debris the size of a grain of rice, which he called "microplastics" on a beach in the United Kingdom. Plastic particles with a diameter of 1~5 mm are called microplastics, and nano-scale plastic particles below 1 micron are called nanoplastics. These two types of microplastics have similar properties and are often referred to collectively as nano/microplastics (NMPs). Microplastics are substances that are formed when plastic products decompose in the environment. Microplastics can be produced during the use, production, and disposal of any plastic product.
Sources of microplastics: The weathering process of irreversible plastic pollution in the environment (Image source: Science article "The Global Threat of Plastic Pollution")
Microplastic recycling
In addition to being absorbed by marine organisms, sinking to the bottom of the sea, or washed up on beaches by ocean currents, marine microplastics can also enter the atmosphere above the ocean through the bursting of bubbles in the ocean or the action of ocean waves. The smaller size and density of these microplastics can be carried far away by the atmosphere, and some of them may be brought back to land.
Microplastic particles flow through the ground, groundwater and surface water, atmosphere, oceans and ecosystems, forming a new biogeochemical cycle - the microplastic cycle.
The global microplastics cycle (Credit: Science article "Global Plastic Pollution Journey")
Sources of ocean plastic
The main pathways of human-generated plastic waste in the marine environment (Credit: From Pollution to Solution: Global Assessment of Marine Litter and Plastic Pollution)
The dangers of ocean plastics
Numerous studies have shown that marine litter, especially plastics and their decomposition products, cause widespread damage to marine organisms and ecosystem functions and may endanger human health.
The lethal and sub-lethal effects of plastic include whales, seals, turtles, birds and fish ingesting plastic that can lead to starvation and tearing of internal organs, as well as depriving coral reefs of oxygen and light by covering them, sea turtles, birds and mammals drowning from entanglement in discarded fishing gear and plastic packaging, and physiological stress and toxicological hazards of plankton, shellfish, fish and marine worms from ingesting microplastics, all of which are critical to ecosystem functioning.
The immediate risks and impacts of marine litter and plastic (Credit: UN report From Pollution to Solution: A Global Assessment of Marine Litter and Plastic Pollution)
What will happen to "eating plastic"?
Microplastics and nanoplastics can pose a risk to human health.
Eating contaminated seafood, exposure to plastic and the disease-causing bacteria it carries can harm human health and may affect fertility, hormones, metabolism and nerve activity.
While the link between ocean plastics and seafood has not been fully demonstrated, and total exposure to ocean plastics and their health effects has not yet been determined, there is substantial evidence that chemicals in plastics, such as methylmercury, plasticizers, and flame retardants, can enter the human body through these pathways and have serious health impacts.
In addition, open burning of plastics can lead to air pollution, and exposure to toxic fumes and carcinogenic chemicals from open burning and incomplete incineration can have serious impacts on informal waste disposal workers.
In March 2024, the authoritative journal New England Journal of Medicine published a study that confirmed for the first time that there is a link between microplastics and nanoplastics and the risk of disease death in humans. Scientists anatomically looked at 257 patients who had undergone carotid endarterectomy and found traces of microplastics in plaques that had blocked blood vessels in their necks and were removed. And the more microplastics in the plaque, the worse the patient tends to end up doing.
The study followed these patients for an average of 34 months after surgery. The results showed that 30 of the 150 patients (20%) who had microplastic particles found in the plaques had heart attacks, strokes, or all-cause deaths. Of the 107 patients who did not have plastic detected, only 8 (7.5%) experienced similar results.
Plaque and microplastic particles under an electron microscope (Image source: New England Journal of Medicine)
Although the current research still has no clear conclusion on whether microplastics are harmful or not, it will take a long time for humans to understand the impact of microplastics on us.
In addition to their potential hazards, microplastics can also act as carriers of organic pollutants, heavy metals and microorganisms, transporting them through the environment and between the food chain.
War, war, global war plastic!
April 22, 2024 is the 55th anniversary of Earth Day. The theme of this year's Earth Day is "Planet vs. Plastics", which aims to call for widespread attention to the health risks posed by plastics, the rapid phase-out of all single-use plastics, the urgent push for a strong global plastic pollution treaty, an end to "fast fashion", and a plastic-free planet for future generations!
Earth Day 2024 poster (Image source: Earth Day official website)
Plastic production is soaring!
Plastic production soared from 2 million tonnes per year in 1950 to 377 million tonnes in 2019, of which only 3.8 million tonnes were bio-based and 373 million tonnes were fossil-based. In the first 20 years of the 21st century, global plastic production doubled.
Global annual production of plastics from 1950 to 2019 (Image source: Green Carbon article "Towards greener polymers: trends in the German chemical industry")
Plastic waste is growing!
Plastic pollution has become a global problem! Plastics are inexpensive and versatile, with almost half of all plastics used to make short-lived or single-use products that can take hundreds of years to degrade.
As of 2015, 60% of all plastic ever produced has reached the end of its useful life and is discarded, and less than 10% of plastic products are recycled. In 2019, only 33 million tonnes of plastic were recycled, accounting for only 9% of the 353 million tonnes of plastic waste. By 2060, the world's plastic waste will nearly triple in size, with about half of it going to landfill and less than 20% being recycled.
How much plastic is produced, how much plastic is wasted, and how much is in the environment? (Image source: Organisation for Economic Co-operation and Development report)
Plastic is everywhere!
Microplastics are everywhere, in the ocean, freshwater, drinking water, food and air. Even more outrageous, scientists have detected the presence of microplastics even in the snow of the Arctic.
Plastic is everywhere and in almost every garbage dump in the world......
Plastic in the garbage dump (Credit: WWF report)
Plastic is everywhere on almost every beach in the world...... About 11 million tonnes of plastic waste flows into the ocean every year. By 2040, this number could increase by a factor of 2.
Plastic pellets on a sea stall (Credit: WWF report)
Global War Plastic, Historic Resolution!
Plastic production and pollution create a "triple crisis" – climate change, nature loss and pollution – on the planet on which we all depend, and cause a catastrophe.
So, on March 2, 2022, at the United Nations Environment Assembly in Nairobi, Kenya, heads of state, environment ministers and other representatives from 175 countries adopted a historic resolution to develop a legally binding international agreement by 2024. The resolution addresses the entire life cycle of plastics, including their production, design and disposal.
How much of a climate impact does plastic have? Plastics have been criticized for their toxicity and pollution of the oceans, but they play an important role in improving efficiency and reducing greenhouse gas emissions. Studies have shown that in most cases, plastics contribute less to greenhouse gases than plastic alternatives.
Plastic pollution, how to deal with it?
Tackle plastic pollution, reduce the use of the most problematic and unnecessary plastics, and transform the market to achieve plastic circularity. Achieving this goal will require accelerating three key shifts – reuse, recycle, reorient & diversify, and taking action to address the legacy of plastic pollution. "Reuse" refers to the shift from a "single-use economy" to a "reusable society" where the reuse of plastic products makes more economic sense than discarding them. "Repositioning and diversifying" means driving the market towards sustainable alternatives to plastics.
Tackling plastic pollution requires accelerating three key shifts: reuse, recycling, repositioning and diversification (Credit: UNEP report)
The mainland bans production!
China is the world's most active economy in the production, consumption and import and export trade of plastics. During the period from 1950 to 2010, the production of primary plastics in China showed an exponential growth trend, and since 2010, it has significantly deviated from the exponential growth trajectory and decelerated its growth. In 2020, China's annual output of primary plastics exceeded 100 million tons for the first time, accounting for 28% of the world's total output, with a consumption of 130 million tons and an import of 40.63 million tons, with an import dependence of 25.5%, a decrease of nearly 5 percentage points from the 2015 level (30.4%).
China's primary plastic production from 1950 to 2025 (Photo source: Peking University report "Research Report on the Green and Low-Carbon Development of China's Plastics Industry")
The mainland has made it clear that it strictly prohibits the production of products that harm the environment and human health, such as ultra-thin agricultural mulch film and daily chemical products containing plastic microbeads, and encourages the public to reduce the use of single-use plastic products. Strengthen the classification and recycling of plastic waste, accelerate the construction of domestic waste incineration treatment facilities, and reduce the amount of plastic waste landfilled.
How is the U.S. responding?
In January 2023, the U.S. Department of Energy released the "Plastics Innovation Strategy", which proposes four strategic goals: (1) Deconstruction: Develop new chemical, thermal, and biological/hybrid pathways to efficiently decompose plastics into useful chemical intermediates. (2) Upcycling: Promote scientific and technological progress to upcycle chemical intermediates obtained from plastic waste into high-value products. (3) Design recyclable plastics: Design new renewable plastics and bioplastics to make them have the characteristics of traditional plastics, be easy to upcycle, and can be mass-produced in China. (4) Expansion and Deployment: Support energy- and material-saving domestic plastics supply chains by helping companies expand and deploy new technologies in domestic and global markets, while improving existing recycling technologies such as collection, sorting, and mechanical recycling.
4 U.S. Strategic Goals: Deconstruct, Upcycle, Design Recyclable Plastics, Scale and Deploy (Credit: U.S. Department of Energy's Plastics Innovation Strategy)
In April 2023, the U.S. Environmental Protection Agency released the Draft National Strategy to Prevent Plastic Pollution. The strategy identifies three key objectives: (1) Reducing pollution in the production of plastics. (2) Improve the management of post-consumer plastics. (3) Prevent garbage and micro/nano plastics from entering waterways and remove garbage escaping from the environment.
Fight, fight, scientific war!
There are many ways to fight scientifically. Here are a few of the latest developments in plasticizers, plastic degradation, and pulp foam materials from the Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences.
Polyvinyl chloride (PVC) is one of the world's five general plastics, and plasticizers are important modifiers necessary for the processing of PVC industry. At present, the most widely used is that petroleum-based phthalate plasticizers are gradually restricted due to biological toxicity, improved petroleum-based plasticizers are difficult to adapt to the increasing performance requirements, and the plasticization performance or production cost of existing environmentally friendly bio-based plasticizers is still uncompetitive. Using the integration strategy of biosynthesis and chemical catalysis, the researchers have developed a new generation of safe, environmentally friendly, efficient plasticizer, long-term and stable bio-based plasticizers based on trans-aconitic acid, which is expected to partially replace the traditional petroleum-based phthalate plasticizers and serve human health and the natural environment.
Green biomanufacturing of new bio-based plasticizer trans-aconitate (Image source: Green Carbon)
As a polymer material, plastic is a polymer chain formed by the polymerization of thousands of monomers. Chemical degradation refers to the chemical breaking or recombination of these polymer chains to depolymerize into polymerized initial monomers or into other high-value chemicals and macromolecules. The researchers used a selective continuous "one-pot method" depolymerization strategy to achieve chemical recycling of commercial and hybrid plastics. The recycled monomers can be repolymerized to make new plastic materials, thus enabling plastic recycling.
Chemical degradation of waste plastics (Image source: American Chemical Society - Sustainable Chemistry and Engineering)
The market size of fossil raw material-based foams in mainland China is huge, but these foams are not degradable and have caused serious "white pollution". The use of renewable and biodegradable cellulose to prepare porous materials has a wide range of application prospects in the fields of packaging, construction, medical and health care, and chemical industry. The researchers used a boron crosslinking strategy combined with the synergy of chitosan and a small amount of cationic polyacrylamide to develop a high-strength, fire-resistant, antimicrobial pulp foam.
A new material of high-strength, fire-resistant, and antibacterial pulp foam (Image source: Carbohydrate Polymer)
What types of plastics are there?
According to the material properties, plastics are divided into two categories: general plastics and engineering plastics (as well as some special plastics), and according to physical and chemical properties, they are divided into two categories: thermoplastics and thermosetting plastics.
Classification of plastics based on physical and chemical properties (Source: Research Report on Green and Low-Carbon Development of China's Plastics Industry, Report by the Energy Research Institute of Peking University)
How much plastic do you eat in a day?
Evidence from clinical studies suggests that plastic can enter the body through ingestion, inhalation, and skin absorption, and accumulate in organs, including the placenta. In 2020, the American Chemical Society reported that microplastics had been detected in human lungs, liver, spleen, adipose tissue, and kidneys.
Microplastics and nanoplastic particles in human contact (Credit: UN report From Pollution to Solution: A Global Assessment of Marine Litter and Plastic Pollution)
Indoor and outdoor air contains different amounts of microplastics. Various foods also contain different amounts of microplastics. Microplastics contain toxic additives to varying degrees, and the ways and means of exposure to these additives also involve all aspects of life.
It is estimated that we consume about 5g of plastic per week on average – the equivalent of a bank card.
Human exposure to plastic particles and related chemicals (Credit: UN report From Pollution to Solution: A Global Assessment of Marine Litter and Plastic Pollution)
Three tips for "eating" less microplastics
We know that plastic degradation often takes hundreds or even thousands of years, which puts ingested microplastics at risk of accumulation in the body. In order to avoid human internal organs becoming "plastic products", the easiest way is to "eat plastic" less.
(1) Boil water before drinking, and reduce microplastics by 80%.
Schematic diagram of the process of scale carrying away microplastics (Image source: Environmental Science and Technology)
(2) Use less plastic containers and paper cups to heat food and fill hot food.
(3) Try to eat as little seafood offal as possible.
Start with me, start with Earth Day!
In our daily lives, what we can do is to use less or no plastic products and pay attention to recycling plastic products.
Ditch plastic bags and use eco-friendly bags (Credit: UN report Cutting the Root Causes – How the World Can End Plastic Pollution and Create a Circular Economy)
(Source: China Science Expo)