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Marine Plastic Debris, Where Are They From?

There are 13 times more plastic residues in our oceans than the stars in our Milky Way. About 400 million stars are in our galaxy, while 5.25 trillion pieces of plastics stay in our oceans (Li et al, 2015). Any garbage which finds its way into the ocean is called marine debris. Ranging from bottles, aluminum cans, to a bicycle wrecks, massive quantities of marine debris circulate across the globe. The vast majority of marine debris is plastic. Have you ever wondered how these abundant debris can end up in our ocean? 

We can classify the sources of marine debris into two types based on where they come from, debris comes from human activities in land and from human activities in ocean. The first type is land-based sources of marine debris. These sources dominate the whole supply of the plastic debris in sea environment. The terrestrial waste contribute approximately 80% of the total plastic debris in the marine environment (Li et al, 2015). The land-based marine debris includes poorly-managed landfills, riverine transport, untreated sewage and storm water discharges, industrial and manufacturing facilities with inadequate controls, wind-blown debris, recreational utilization of coastal areas, and tourism irresponsible behavior. (Barnes et al. 2009).  

The combination between wrong behaviors toward plastic consumption and poor waste management generate land-based marine debris. The activities that seems to be common in daily life can cause the plastic debris in our ocean. People often leave trash on beaches. People who live near the river often throw their domestic waste into the water stream such as sewer or river. At the end of the day, consuming plastic without being able to manage the waste lead the plastics easily polluting the ocean.

Even though, the land-based debris is perceived as the major source of marine debris, the regional variations influence which channel plastic entering ocean the most. How about in Asian region? Which stream contribute more debris to our ocean? 

Lebreton et al. (2017) argue that rivers in Asia supply about 67% of the global annual plastic waste into the marine environment.  One of the rivers in Asia, Yangtze River, is proved as the largest source of plastic waste. It transfers approximately 330,000 tons plastic into ocean in 2015 (Lebreton et al., 2017). Another research from Jambeck et al. (2015) estimates that there is a total amount of 4.8 to 12.7 million tons of plastic waste, from 192 coastal states, discharged into the marine environment. Furthermore, the Asian region is the red spot of inadequate management or mismanagement for plastic waste, especially in China, Indonesia, Sri Lanka and India (Jambeck et al., 2015). It was predicted that unless the plastic waste management and littering behavior been better, the amount of plastic waste dumped into the sea will increase significant times in 2025.

The second source of marine debris is the ocean-based debris. Despite this source is perceived to contribute only 20% of marine plastic debris, knowing the source can be a good start to minimize the debris. There are some human activities in ocean leading to marine debris oil rigs, cargo transportation, and shipping activity. Nevertheless, the major activity in sea region that can result plastic debris in marine environment are commercial fishing (Li et al., 2015). Let us see the data in the far past time. More than 40 years ago, in 1975, the sinking of a fishing fleet resulted in the deposition of 135,400 tons of plastic fishing gear and 23,600 tons of synthetic packaging material into the sea (Cawthorn, 1989).

The amount of the plastics marine waste from 45 years ago was already a lot. What are the present circumstances? It just gets worse. The amount of fishing gear lost to the environment has quadrupled at the present time. An estimation of 640,000 tons of discarded fishing equipment are added annually into the ocean, representing roughly 10% of the total marine debris (Good et al., 2010).  Such discarded fishing items, including monofilament lines and nylon netting, float at different depths within the sea, resulting in “ghost fishing,” and can cause aquatic organisms to become entangled (Lozano and Mouat, 2009). We can see that there is a linier correlation between the numbers of ocean-based plastic debris and the level of commercial fishing.

From the explanation above, we understand that the debris in our ocean is resulted by human activities either in land or in ocean itself. Plastic is the biggest composition of debris in marine environment. The irresponsible attitude towards plastic consumption, littering behavior in river system, commercial fishing activity, and low quality landfill management are the main causes of the abundant plastic pollution in the sea. Human activity and behavior are the causes of marine debris, reciprocally, human are also the main solution to save our ocean, besides the technology in managing plastic waste in land to prevent them polluting the ocean. 

 Written by: Rio Alfajri


Barnes, D.K.A., Galgani,F., Thompson, R.C.,Barlaz, M., 2009. Accumulation and fragmentation of plastic debris in global environments. Philos. Trans.R. Soc., B364,1985–1998.

Cawthorn, M., 1989. Impacts of marine debris on wildlife in New Zealand coastal waters. Proceedings of Marine Debris in New Zealand’s Coastal Waters Workshop, 9 March 1989. Department of Conservation, Wellington, New Zealand, pp. 5–6.

Good, T.P., June, J.A., Etnier, M.A., Broadhurst, G., 2010. Derelict fishing nets in Puget Sound and the Northwest Straits: patterns and threats to marine fauna. Mar. Pollut. Bull. 60, 39–50.

Jambeck, J.R., Geyer, R., Wilcox, C., Siegler, T.R., Perryman, M., Andrady, A., and Law, K. L., 2015, Plastic waste inputs from land into the ocean. Science 347(6223), 768–771.

Lebreton, L.C.M., Zwet, J.V.D., Damsteeg, J.W., Slat1, B., Andrady, A., and Reisser, J., 2017, River plastic emissions to the world’s oceans. Nature Communications 8, 15611. doi:10.1038/ncomms15611

LI, W. C., Tse, H. F., & Fok, L. (2016). Plastic waste in the marine environment: A review of sources, occurrence and effects. Science of the Total Environment, 566, 333-349.

Lozano, R.L., Mouat, J., 2009. Marine Litter in the North-East Atlantic Region: Assessment and Priorities for Response (KIMO International).

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