Marine Plastic Pollution

Marine plastic pollution refers to the accumulation of plastic debris and particles in the world’s oceans and other water bodies.

Marine plastic pollution has emerged as one of the major threats to the health of ocean and marine biodiversity.

It has been estimated that 8 million tons (Mt) of plastic waste reaches the ocean and makes up 80% of all marine litter.

Scientists have further projected that with no action taken, the volume will double by 2030.

It has serious implications on food safety and quality, human health, coastal tourism, and fishing industry.

Marine Plastic: Types and Distribution

Macro plastics (i.e., items > 5 mm diameter) Examples: disposables, plastic bags, etc. Macro plastic degrades into microplastics due to different process such as hydrolysis, photodegradation, physical degradation.

Micro plastics ((i.e., items < 5 mm diameter). Example: micro beads, fishing line fragments etc. Microplastics are further categorized into primary and secondary sources.

• Primary sources include manufactured products such as micro beads in cosmetics.
• Secondary micro-plastics are formed from the breakdown of macro-plastics.

 Nano plastics (<100 nm size range): These are formed due to further degradation of microplastics.

Plastic waste can be found along the shorelines, floating on the water surface, in the entire water along and even deposited in the sediments.

The distribution of plastic waste is dependent on variety of factors such as:

• Density and buoyancy of the plastic particle
• Ocean currents
• Wind
• Oceanic geographical characteristics (e.g., shallow vs. deep areas; Confined areas vs. Open Ocean)
• Proximity to urban areas, waste water treatment plants, fishing
• Proximity to shipping lines

Plastics which are relatively more buoyant remains close to the ocean surface. Only 1% of marine plastics are estimated to float at or near the ocean surface

The long-range transport and accumulation are influenced by the surface ocean circulation. The concentration increases at certain mid-oceanic region near the gyres.

Gyre: A gyre is a large system of rotating ocean currents. Gyres circle large areas of stationary, calm water. When plastic waste drifts into these areas, due to the region’s lack movement, they tend to accumulate and form “garbage patches”.

Marine Plastic Pollution: Sources

According to estimates, 80% of plastic pollution in ocean comes from land-based sources with the remainder comes from ocean-based sources.

Land-Based Sources:

• Rivers as Conduits: Rivers act as conduits of waste from the land to the ocean. Municipal waste, waste from dumpsites discharged into rivers ultimately flows into the oceans.  10 river- systems viz. Niger, Nile, Indus, Ganges-Meghna- Brahmaputra, Hai-He, Amur, Huang-He, Chang-Jiang, Zujiang and Mekong are estimated to carry more than 90% of the plastic waste that ends up in the oceans.
• Sewage: Many untreated sewage outlets discharge directly in to the sea contaminated with microplastics. For example, a study had found that Mumbai releases 2,100 million litres waste water sewage into the Arabian Sea each day.
• Dumping: In absence of adequate waste disposal, waste including plastic waste is often illegally dumped into the oceans directly.
• Industrial activity: Inadequate disposal of products, or loss during transport often result in plastic waste being released into the seas and oceans.
• Coastal littering: Tourist in beaches often leave behind plastic waste such as plastic bags, food wrappers, plastic bottles, straws etc. which ultimately ends up in the seas and oceans.
• Natural disasters: Natural disasters such as cyclones and tsunamis often leads to waste being released into the oceans. For example, in 2011, East Japan tsunami contributed nearly five million tons of debris including plastic into the ocean.

Sea-based Sources: 

• Fishing: Due to fishing activities, nets, lines and rope etc. are often dumped or released accidentally into oceans.
• Shipping: Cargo ships often accidentally release waste including plastics into the ocean.
• Sea-based activities: Sea-based activities such as offshore oil and gas platforms, shipping commercial shipping, and undersea exploration contribute to ocean plastic litter.

Marine Plastic Pollution: Impact

On Physical Environment of the Ocean:

• Scientists from Marine and Environmental Sciences Centre have discovered a new type of plastic pollution which is called, “ Plasticrusts”. It is a layer of plastic encrusted onto ocean rocks.
• Plastic accumulation reduces light penetration and oxygen concentration in oceans
• Concentrations of microplastics in beach sediments can lead to changes in physical properties, permeability and flow of nutrients and subsurface temperature. 

On Marine Biodiversity: 

• Numerous aquatic organisms ingest plastics which often lead to physical damage or blockage of the intestinal tract, which can lead to infection, starvation, reduced reproductive ability and potential death.
• Further, ingestion of persistent organic pollutants which concentrate further through the marine food chain can lead to bio accumulation and bio magnification.
• Entanglement in nets, ropes and other plastic debris is fatal for marine animals.
• Floating plastic act as a vector for the transport of non-native and invasive species, harmful algal blooms, viruses and microbial communities, which disturbs the marine ecosystem and species diversity.
• Plastics accumulated in coral reefs increases the risk of diseases in corals by blocking light and oxygen reaching the reefs.

On Human health: 

• Contaminants from plastic waste accumulate in the food web through ingestion by marine organisms, posing a potential public health threat to humans who consume seafood.
• According to The New Plastics Economy report, people worldwide could be ingesting 5g of microscopic plastic particles every week.
• Such consumption could have potential threats of interfering with the endocrine system, causing developmental, reproductive, neurological, and immune disorders.
• Microplastics have also been found in drinking water, salt etc.

On Economy:

• According to UNEP, impacts related to plastic pollution in oceans cost up to $8 billion a year.
• Plastic waste reduce tourism potential of coastal cities and islands due to loss of aesthetic value.
• Huge economic costs are incurred due to beach clean-ups initiatives, waste management in marinas and harbours.
• Discarded or lost fish nets cause ‘ghost fishing’ which results in reduced fishery stocks available for commercial fishing. This leads to significant economic loss for coastal fishing communities.

Marine Plastic Pollution: Preventive Measures

• Sustainable Development Goal 14 and its target 14.1, seeks to prevent and significantly reduce marine pollution of all kinds- land-based, sea-based activities and nutrient pollution.
• UN Convention on the Law of the Sea, 1982 calls signatory states to develop a legal framework to prevent, reduce and control pollution of the marine environment by dumping. India is a signatory to UNCLOS
• International Convention for the Prevention of Pollution from Ships (MARPOL) is adopted in 1972, it bans the disposal of plastics in the sea. India is a signatory to MARPOL.
• London Convention also known as Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter,1972 seeks to provide effective control of all sources of marine pollution. India is not a party to the London Convention.
• UNEP Draft Resolution on Marine Plastics and Microplastics, 2017 calls for voluntary commitments to reduce and prevent marine plastic pollution and microplastics.
• G20 Action Plan on Marine Litter, 2017, at G20 Hamburg Summit in Germany, the plan seeks to promote and initiate measures and actions at local, national, and regional levels to prevent and reduce marine litter.
• Merchant Shipping Rules, 2009 framed under the Merchant Shipping Act, 1958 deals with prevention of marine pollution in India.
• Plastic Waste Management Rules, 2016 bans plastic bags below the thickness of 50 microns. It also calls for phasing out of manufacture and use of non- recyclable multi-layered plastic in 2 years.

Marine Plastic Pollution: Proposed Solutions

1.Circular Plastic Economy:

• Circular plastic economy is a sustainable long-term solution in which value of plastic is kept within the economy rather than leaking it out to the natural environment.
• The concept is based on 6 ‘R’s: a) Reduce (raw material use), b) Redesign (design products for re-use or recycling) c) Remove (single-use plastics when practical), d) Re-use (alternative uses or for refurbishment), e) Recycle (to avoid plastics going to waste) and f) Recover (re-synthesise fuels, carefully controlled incineration for energy production)

2.Improved Waste Collection and Management:

• To combat marine plastic pollution, investments should be made towards recycling, waste-to energy plants.
• For example, in Sweden less than 1% of waste in Sweden ends up in landfills.
• ECOBOT in Colombia is a Reverse Vending Machine which is located in shopping malls, institutions, and public spaces and encourages the process of recycling the PET bottles.

 3.Investment in Environmentally Sound Alternatives:

• Legislation and financial incentives should be provided to develop environmentally sound alternatives plastic. Example: paper and jute bags.

 4.Market Based Instruments:

• Deposit refund Schemes: Under the scheme, at the time of purchase the consumers have to pay a small deposit for the objects bought. The money is given back when he returns them.Example: automatic ‘return-deposit’ machines in Germany and Finland which returns of up to 90% of the amount for PET.

• Payments and Awards: Payments can be provided to fishermen for reporting on and removing of litter.Example: in South Korea the government had established a compensation ‘buy-back’ scheme for fishermen that removed nets and other litter from sea.

• Taxes and fees: These are effective tools to discourage inefficient use of resources and polluting behaviour.Example: In India, under the plastic waste management rules, no carry bags should be made available free of cost by retailers to consumers

• Fines: Fines can be imposed to discourage polluting behaviour. However, implementation and enforcement is the key to efficiency of such measure. Example: Hong Kong had introduced Fixed Penalty Ordinance in 2002. Under the law, a fine of $1,500 can be imposed against marine and near shore littering. 

Ocean Clean Up Project: Netherlands-based engineering NGO Ocean Clean up, has developed a floating device designed to collect plastic waste from the Great Pacific garbage patch.

5.Effective Extended Producer Responsibility:

• It is important to legislate robust extended producer responsibility for all plastic producing sectors.
• This would help ensure greater accountability of companies in management of the plastic waste originating in their trade chains.

6.Clean-up Measures:

• Lost, abandoned or discarded fishing gears can be removed in a sustainable way.  Example: Global Ghost Gear Initiative a cross-sectorial alliance which undertakes a number of ghost net removal initiatives.
• International Coastal Clean-up (ICC) is a global project co-ordinated by the Ocean Conservancy. Under the project, litter surveys and beach clean-ups are taken up.
• Beach Please is a clean-up programme that targets plastic pollution along Mumbai’s coastline.

Marine plastic Pollution is one of the gravest environmental threats the Earth is facing today. It is high time that national governments take effective measures to combat the menace and educate people. Changing social attitudes will have a significant effect on consumption patterns, littering behaviour and success of anti-pollution strategies.