Plastic, a new type of "invasive species", is devouring the oceans on which we depend for survival. If humans do not take any action, the weight of plastic waste in the ocean will exceed that of fish in 2050, and human life and health will also be threatened.

On March 16, 2019, the body of a male baby whale was found in Davao Bay, Philippines. After dissection, scientists found that there were about 40 kilograms of plastic waste in its stomach, many of which had hardened. The plastic in the stomach has long occupied space, and it cannot get enough food and water. The whale starved to death.

On July 14, 2018, local time, in Bruges, West Flanders, Belgium, an art installation of a 10-meter-long giant whale leaping out of the "Pacific Ocean" made of 5 tons of plastic waste was exhibited. Photo/Visual China Such news is common, and the pictures are often shocking. Since it was put into use in the 1950s, the production of plastic has shown an exponential growth and is discharged into the ocean through various channels. Plastic waste has gradually become the largest, most harmful and most persistent marine waste.

In March 2022, the fifth United Nations Environment Assembly resumed its historic resolution: "Ending Plastic Pollution: Towards an Internationally Legally Binding Instrument", with the goal of reaching a legally binding agreement by the end of 2024. The resolution proposes that ending is not the same as eliminating, but promoting the sustainability of plastics and reducing plastic pollution from the entire life cycle of plastic production, consumption and recycling. The first intergovernmental negotiations were launched on November 28.

Ubiquitous plastic waste

Plastics were once called "one of the greatest inventions of the 20th century" and have brought earth-shaking changes to human life, but their cost is also huge.

According to data released by the United Nations Environment Programme in 2021, the world's cumulative production of plastics is currently 8.3 billion tons. In the past four decades, production has more than quadrupled, but the overall recycling rate is less than 10%. There are nearly 100 million tons of plastic waste in the ocean, and about 9 million to 14 million tons of plastic continue to flow in every year, and it is increasing year by year.

A large number of plastic products such as fibers, building materials, and food bags will eventually enter the ocean through landfills, sewage treatment plants, and airborne transmission after incineration.

Photo/Visual China

According to a report by the World Wildlife Fund in October 2021, land-based garbage caused by improper management accounts for more than 70% of the total amount of marine garbage, of which river input is the main way, and rivers will send about 800,000-2.7 million tons of plastic garbage into the ocean every year. In addition, plastic waste leakage from marine transportation, fisheries, and aquaculture also accounts for a small part.

At present, there is at least one garbage belt in every ocean, the largest of which is the North Pacific garbage belt, with an area of 1.6 million square kilometers, equivalent to the area of the entire Mongolia.

Due to rapid economic growth, dense population, long coastline, and backward garbage disposal capacity, Southeast Asia has become a hot spot for marine plastic pollution control.

Ji Junhui, director of the National Engineering Research Center for Engineering and Ecological Plastics at the Institute of Physical and Chemical Research of the Chinese Academy of Sciences, said that as the most densely populated region in the world, Southeast Asian countries have experienced rapid economic development and increasing plastic consumption, but the backward garbage disposal system is simply unable to cope with it. Marine plastic reduction has become an issue that cannot be ignored by all countries.

Plastic waste causes the most obvious harm to marine life. Fish and birds are affected by entanglement or accidental ingestion, and seabed microorganisms and coral reefs die because the sun is blocked and they cannot grow.

A turtle tightly entangled in a fishing net. Photo/Visual China

In addition, there is another type of plastic that is ignored by humans, but it is extremely harmful, that is, microplastics. This includes crystals in toothpaste and detergents, fibers on the surface of clothing, and plastic particles that are decomposed under the action of seawater erosion and sunlight.

Microplastics are highly diffuse and difficult to detect with the naked eye. They are carried to every corner of the earth by ocean currents. In microplastic hotspots, there are 1.9 million plastic particles per square meter of seawater.

Chen Yuan, director of the Regional Chemicals Management Office of the Basel Convention Asia-Pacific Regional Center of the United Nations Environment Program, said that microplastics will absorb and carry pollutants in the environment, and will continue to accumulate along the food chain, eventually posing a threat to human health.

It is urgent to cut off the increase

Plastic waste flowing into the ocean is increasing. To achieve marine plastic reduction, we must first cut off the increase and always adhere to the concept of sustainability from the design and production of plastics to the consumption link.

Ji Junhui said, "Excessive use can be controlled, but use cannot be controlled." Plastics have penetrated into every corner of human life. Degradable plastics as substitutes will help effectively control plastic pollution from the front end of the industrial chain.

At present, there are biodegradable plastics such as polylactic acid (PLA), polybutylene succinate (PBS) and its copolyester (PBAT), which can be decomposed and digested by microorganisms and eventually form carbon dioxide and water. At the 2022 Beijing Winter Olympics, PLA tableware and PBAT plastic bags were widely used. There are also food packaging bags made of seaweed in Indonesia, and edible straws made of rice in South Korea.

Garbage on tropical beaches and in the water. Photo/Visual China

But being degradable on land does not mean it can also be achieved in seawater. Ji Junhui explained to reporters that compared with land, the microorganisms in seawater are negligible, and the temperature is lower, so the existing biodegradable plastics are difficult to contribute to the reduction of plastic in the ocean.

Since 2017, Ji Junhui's team has been working hard to overcome difficulties in the seawater environment and finally developed fully natural domain degradable plastics. This new material retains the performance and appearance of the original plastic, and can be degraded in both marine waters and soils. It can be used in major plastic products such as fishing nets, plastic bags, and plastic bottles. The technology has now entered the pilot stage and is exploring the future of industrialization.

Ji Junhui said that fully natural domain degradable plastics are not an upgrade of biodegradable plastics, but a brand-new disruptive technology. With the improvement of technology and the reduction of costs, there will be greater room for development. However, since the replacement of plastic products requires functions, costs and production scale to keep up, this will be a long process.

In the consumption link, countries have successively introduced governance policies such as deposits, fines, taxes, and plastic restrictions, focusing on combating the most common disposable plastic products.

The European Union issued the "Single-Use Plastic Directive" (SUPD) in 2019, and ten common products such as disposable tableware and beverage bottles were banned from using plastic production, and even banned from using degradable plastic production. The ban is so strict because existing degradable plastics cannot solve the problem of marine plastic pollution.

In 2020, China issued the "Opinions on Further Strengthening Plastic Pollution Control", restricting the use of a variety of non-degradable disposable plastic products, including tableware, plastic bags, etc., which is called the "strictest plastic restriction order in history" by the Chinese industry.

On July 31, 2019, in Qingdao, a slogan in the farmers' market "Implement the plastic restriction order to reduce white pollution." Photo/Visual China

Chen Yuan said that the main way to reduce the increase in marine plastics is to strictly manage land-based plastic waste, standardize marine operations, and improve the ecological design of plastic products in the upstream link, reduce the consumption of plastics, especially disposable plastics, in the midstream link, and increase the initiative and enthusiasm of the whole people to participate in plastic reduction.

Reducing the stock is a long way to go

Faced with the huge amount of marine plastic waste, recycling is a necessary means, but the reality still exists.

Chen Yuan said that the degradation rate of waste plastics in the ocean is slow and needs to be manually cleaned, but the cost is high and the difficulty is great. There is no large-scale action to remove marine plastics.

Ji Junhui also lamented, "Humans are helpless against the plastics that already exist in the ocean."

The current mainstream methods for plastic waste treatment include mechanical crushing, incineration power generation, thermal decomposition and solvent decomposition. Some scientists have also found upgraded marine microorganisms that can effectively degrade a variety of plastics in seawater environments. However, the academic community is still concerned about whether the application of such microorganisms will cause damage to existing marine infrastructure, underground pipelines, etc., and whether the cost is too high to achieve industrialization.

On June 23, 2021, local time, in Tlaquepaque, Mexico, local companies are encouraged to recycle plastic fragments and use these garbage to produce practical, durable and recyclable products. Photo/Visual China

Ji Junhui told reporters that there are three types of plastics that are difficult to recycle. The first is uneconomical recycling, such as plastic bags, plastic foam and other cheap products. The second is non-recyclable, such as paint buckets, pesticide barrels and other plastics that may come into contact with toxic and harmful substances. There are also recycling technologies that are difficult to achieve, such as microplastics that are difficult to detect but ubiquitous in the ocean.

Zhang Yanfeng, deputy dean of scientific research at the School of Chemistry of Xi'an Jiaotong University, said in an interview with a reporter from Global Magazine that there are many types of recycled plastics. Many products are not only made of one material, but also the processing of some products makes them unable to be recycled in the future. "This is not a technical problem, but a practical problem. Solving the problem will take decades or even hundreds of years."

To end marine plastics, it is necessary to manage plastics throughout their life cycle.The reuse and recycling of plastics should be taken into consideration at the design stage, and degradable technologies should be developed to carry out fine classification at the source. And we should focus on diversified ways to control plastic pollution and form a network and industrial chain for the recycling of waste plastics. At the same time, we should raise the awareness of the ban on plastics among the whole people, establish a new concept of environmental protection, and reduce the generation of plastic pollution at the consumer end.

Ji Junhui said that reducing plastic in the ocean is a problem for the whole society and all mankind, and every link needs to pay attention, take responsibility, and work together.

Written by: Guo Xixian

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