Several ways for plastic garbage to enter the ocean;
1. Dump directly into it. For some plastic wastes with no recycling value, in order to reduce the cost, they are either directly burned or dumped into rivers and finally merged into the ocean. This phenomenon is particularly common in rural areas of China, and at present, the treatment capacity of landfill sites in China is mostly saturated, and there is no matching treatment capacity with a large number of plastic wastes. In addition, some of them are daily garbage produced by human life, which are randomly discarded in rivers, beaches and the sea due to the incomplete recycling system and the lack of environmental awareness. The widespread use of disposable plastic packaging aggravates this situation, and the related garbage collection system may be underdeveloped or even non-existent.
2. Sewage outlet. Mainly discharged into rivers through sewage pipes of sewage treatment plants. The waste water of industrial products may contain plastic particles, and in some places where supervision is not strict, large pieces of plastic waste may be directly discharged with the waste water through the sewage outlet.
3. Secondary pollution caused by improper garbage disposal
(1) landfill leachate pollution caused by improper landfill. The plastic particles contained in these leachate will penetrate deep into the soil and pollute the groundwater. The groundwater and the water flow in inland lakes are complementary, and these polluted groundwater will enter the river through the lake and finally flow into the ocean.
(2) Non-standard treatment of plastic recycling family workshops in China. In these small workshops, it is often necessary to use a lot of clean water to clean plastic waste, and these plastic-washed wastewater will not be treated harmlessly, so it will directly carry a large number of plastic particles or even whole pieces of plastic into the river. Like these sewage, the remaining plastic garbage residues will be directly dumped on the river bed.
4. Maritime activities
Including marine aquaculture and fishing, exploration and development, all kinds of garbage and ship coatings discharged during the ship’s driving. Some large-scale maritime accidents, such as capsizing of ships and leakage of raw materials, will also lead to plastic waste entering the boundless sea.
What impact will plastic waste have on the ocean?
People call the plastic garbage floating on the ocean the "seventh continent" as a whole, and plastic pollution has become the "unbearable weight of life" for many marine creatures in the vast ocean.
The harm of plastics to wild animals is unimaginable to human beings.
Maybe you never thought that the plastic rope you threw away would sink into the sea and entangle with countless marine life. It is reported that at least 344 species have been caught in the pain of being entangled with plastic so far.Including all turtle species, more than two-thirds of seal species, one-third of whale species and one-quarter of seabirds.
The seemingly dazzling and exquisite packaging plastic paper is also "hidden" after flowing into the sea. Most marine life has eaten plastic fragments by mistake. According to the records of the media and related institutions,At least 233 marine species, including all turtle species, more than one-third of seal species, 59% of whale species, 59% of seabird species, 92 species of fish and 6 species of invertebrates, have ingested plastics..
In addition, touching or colliding with plastic products can also threaten the lives of marine animals. For example, fishing gear has been proved to cause wear and damage to coral reef ecosystem during collision.
The report "Marine Garbage: Understanding, Preventing and Mitigating the Adverse Effects on Marine and Coastal Biodiversity" issued by the Secretariat of the United Nations Convention on Biological Diversity collates the field investigation of polluted marine organisms since 2012. The report shows that plastic pollution has involved various marine biota such as fish, algae, marine birds, marine mammals and marine reptiles.
To make matters worse, plastics are encroaching on the habitats on which marine life depends at an alarming rate. UN Secretary-General Guterres pointed out that pollution, overfishing and the impact of climate change are seriously damaging the health of the oceans. He said that according to a recent study, by 2050, the total weight of plastic waste in the ocean may exceed that of fish.
▍Marine plastics are difficult to degrade.
Plastic is a synthetic macromolecular polymer, and its molecular structure is difficult to be destroyed by biodegradation. If plastic is to be completely degraded into small molecules, a large number of chemical bonds need to be completely broken. For polyethylene molecules, this requires a lot of energy. Therefore, it may take hundreds of years to completely degrade plastics. A BBC report mentioned that a plastic cup can "survive" on the earth for half a century, which shows that the degradation of plastics is very difficult. Unlike land, the refrigeration effect of seawater slows down the degradation process caused by sunlight and high temperature. Therefore, the process of comprehensive decomposition of marine plastic waste is more long and arduous.
-It is difficult to recycle marine plastics.
The vast majority of monomers used to make plastics, such as ethylene and propylene, come from fossil hydrocarbon maps. None of the commonly used plastics is biodegradable. Plastics will eventually accumulate in landfills or natural environments rather than decompose. The only way to permanently eliminate plastic waste is through destructive heat treatment, such as combustion or pyrolysis. Therefore, the near-permanent pollution of the natural environment with plastic waste is an increasingly serious problem. Plastic fragments have been found in all major ocean basins, and it is estimated that the plastic waste entering the marine environment in 2010 alone reached 4-12 million tons. Fresh water system and terrestrial ecological environment are increasingly eroded by plastics.
Nowadays, plastic waste is everywhere.
Sea water is flowing, and plastic will drift to all directions with the water flow; Seawater is also unfathomable, and plastics with different weights and qualities will be divided into different depths. No matter how hard people try, there is no guarantee that there will be no more plastic in the seawater of a certain area. When the plastic is turned into tiny particles, things become more complicated, the difficulty of recycling suddenly increases, and the harm is even greater.
-There are limitations in monitoring marine plastics
1. There are disputes about the data model and sampling method of plastic waste.
A few days ago, a number of experts and scholars announced their monitoring results of microplastics off the coast of China at the APEC seminar on innovative ways to prevent and control marine debris. Although the monitoring scope is the same, their data results are quite different. Luo Yongming, a researcher from Yantai Coastal Zone Research Institute of Chinese Academy of Sciences, said that this is due to the differences in sampling tools and methodology.
Not only are there great differences in domestic research results, but the sampling and research methods of marine plastic waste have not been unified internationally. Li Daoji, a marine environmental expert, once pointed out that the international model research on the amount of marine plastic waste has not measured the amount of plastic waste discharged by various countries, and the research method is still open to question.
2. It is difficult to monitor and treat marine plastic waste.
It is very difficult to track the input and distribution of marine plastics, and there is a great difference between the annual input of plastics and the ocean and the estimated value of surface plastic accumulation. This difference is called the "missing plastic" problem. The monitoring of microplastics is even more difficult, because the particle size of microplastics is very small, and the analysis is very difficult. Therefore, the economic strength of different research teams, the ability to obtain data, the advanced analytical instruments and the feasibility of analytical technology will all have an impact on the monitoring results, which leads to great uncertainty in the monitoring of marine microplastics.
Therefore, it is unrealistic to try to clean up all the plastic garbage in the ocean by manpower. What human beings should do is how to reduce the production and use of plastics, improve the recycling and utilization rate of plastics, and control the source of pollution.
References: Dialogue between China and Foreign Countries; http://aoc.ouc.edu.cn/2a/79/c9824a207481/page.htm in the study of marine development in http://blog.sina.com.cn/s/blog_5dd925170102xgm4.html and China.
Tens of billions of years ago, the first single-celled life on the earth was born in the ocean, but there is no doubt that these white ghosts created by ourselves are slowly destroying the source of life. It is difficult for us to predict where the plastic bottles we throw away will float, just as we can’t predict what node these plastic wastes will bring to the fate of six billion human beings.
data source
National Bureau of Statistics(NBS)
NOAA/Woods Hole Sea Grant
Ocean Atlas 2017
Bulletin on the Environmental Situation of China Coastal Waters in 2016
Bulletin on the State of Marine Environment in China in 2016
Assessment of Municipal Solid Waste Management in China, 2015
Annual Report on Comprehensive Utilization of Resources in China in 2014
Marine litter: understanding, preventing and mitigating adverse impacts on marine and coastal biodiversity.
Jambeck et al. (2015). Plastic waste inputs from land into the ocean.
Laurent C. M. Lebreton et.(2017). River plastic emissions to the world’s oceansNature
Kühn, S., et al., Deleterious Effects of Litter on Marine Life, in Bergmann, M., et al., Marine Anthropogenic Litter, Springer, 2015
IUCN 《Primary Microplastics in the Oceans:a Global Evaluation of Sources》Julien Boucher, Damien Friot
http://onesharedocean.org/LME_48_Yellow_Sea
http://onesharedocean.org/LME_47_East_China_Sea
Instructor: Wu Xiaokun
Graphic editor: Quan Linghui
Team members: Wen Yongshi, Xing Ye, Wang Xinyu and Wu Xi.
