Generally, plastics with particle size less than 5 mm are called microplastics. In recent years, microplastics have attracted more and more attention from academia and the public. Relevant research teams at home and abroad have found microplastics in fresh water, deep sea, soil, Arctic sea ice, snow, air and even food.

So, how to understand the present situation and potential harm of microplastics? How to reduce micro plastics? Our reporter interviewed Li Daoji, Professor of the State Key Laboratory of estuarine and Coastal Science and director of the marine plastics research center of East China Normal University, on the issue of micro plastics.

Concept: microplastics can be divided into types, sizes, shapes and colors

The international attention on microplastics is earlier, and China officially started the marine waste monitoring work in 2007, and the marine microplastics was included in the monitoring scope in 2016.

"Microplastics were first discovered in the ocean." "People also caught a lot of plastic when they caught zooplankton with special nets (the mesh is generally 330 microns)," Li told reporters He said that such nets are currently used to monitor marine microplastics. Manta network, which is the most commonly used to collect microplastics in the surface water of the ocean, has a lot of data about microplastics in the history of Manta network. The microplastics with particle size less than 330 μ M can be obtained by filtration of water body with smaller pore size screen or membrane. "Different methods and equipment apertures can result in very different data."

Microplastics are divided into primary microplastics and secondary microplastics. The former refers to the direct production of micro plastics, such as plastic balls used in cosmetics; the latter is formed by large plastic waste through physical, chemical and biological processes. Li Daoji said that in terms of quantity, the number of secondary microplastics is more.

"Microplastics don't mean a single kind of plastic," Li cautioned. In terms of types, there will be dozens or even hundreds of additives due to different additives; in terms of size, there are millimeter scale, micron scale, and some people think that there are nano scale; the color and shape are also different. Therefore, microplastics is actually a general term

So, in the imagination, there's no such thing as "marine microplastics"

How many micro plastics are there in the global ocean? At present, there is no universally accepted data conclusion in the world. "Plastic in the ocean itself is in a dynamic process, and microplastics are constantly degraded." Li Daoji pointed out.

The distribution of microplastics in the ocean is consistent with that of large plastics. "There are a lot of plastics in the five major ocean eddies, and of course there are also microplastics. Some of them gather in coastal beaches, water bodies, near river estuaries or in some intertidal zones

Compared with the results of similar international surveys in recent years, the content of microplastics in China's coastal waters is at a low level. "The concentration of plastic in China's coastal areas is very small. However, the difference between the north and South rivers is significant, and the concentration level of microplastics in the northern rivers is generally lower than that in some southern rivers

Because of its strong adsorption and long-distance transmission through the atmosphere, microplastics once caused public concern, and even some people thought that eating fish and other seafood would make people "micro plastic poisoning". In this regard, Li Daoji explained that the consequences of microplastics depend on its concentration and quantity. "In fact, at least in the ocean, microplastics do not reach very high concentrations. It is true that microplastics may enter the human body through some food, but it is very small, and the current conclusion is that it is very low risk

"It is not as simple as" big fish eat small fish, people eat big fish "when they eat micro plastics. Marine life is the same as human beings. They eat different things at different growth stages. Our research also found that some marine organisms do not eat microplastics at all. "

Removal: the most effective way is to reduce plastic waste

Plastic not only brings great convenience to people's life, but also causes some ecological and environmental problems due to its improper disposal. "Plastic waste will decompose into micro plastics, so the most effective way to eliminate and 'eliminate' micro plastics is to reduce plastic waste." Li Daoji pointed out.

This year, the national development and Reform Commission, the Ministry of ecological environment and other nine departments jointly issued the "notice on solid promotion of plastic pollution control", which clearly stipulates the prohibition and limit of non degradable plastic bags and some disposable plastic products. On this basis, Li Daoji reminded the general public to change their personal use habits and try to recycle as much as possible. The plastic waste generated must be properly treated to make it enter the regular recycling and treatment system, instead of being thrown into the environment at will.

In the world, the problem of marine plastic waste is also treated as the "number one" environmental problem, and the treatment of micro plastic pollution is given priority. "We hope that through the efforts of all parties, we can finally reach a consensus and urge all countries to take concerted action to promote the introduction of marine plastic waste treatment scheme."

"The problem of marine plastic waste is an international problem, which can not be solved by any country. In addition, plastic waste is persistent and difficult to degrade, and will gradually accumulate in the ocean. If not effectively controlled, it will threaten the entire marine ecosystem Li Daoji stressed.

Source: China Environment News