Oil Spills, Ocean Trash and Debris, Microplastics
Environment & Ecology › Air, Marine, Noise and Other Pollution · Topic 13.14
An oil spill is the release of liquid petroleum into the sea, most often from tanker accidents, ship collisions, pipeline and offshore well failures, and illegal tank washing. Oil spreads as a slick, coats seabirds and mammals, smothers shores and reefs and poisons food chains. Notable spills are Torrey Canyon (1967), Exxon Valdez (1989) and Deepwater Horizon (2010); India has seen the Mumbai collision of MSC Chitra and MV Khalijia-3 (2010) and the Ennore spill after the collision of two ships (2017). Response uses booms, skimmers, dispersants, in-situ burning and bioremediation. Ocean trash and debris is human-made waste in the sea, three-quarters or more of it plastic, found from shores to the deep sea, with large accumulations in ocean gyres such as the Great Pacific Garbage Patch. Microplastics are plastic particles smaller than 5 mm, either made small (microbeads, fibres) or formed by breakdown of larger items, that enter plankton and food chains. Ghost nets lost by fishers keep trapping animals. The Plastic Waste Management Rules, 2016 and the 2022 ban on identified single-use plastics address the problem in India.
5 min read · UPSC Prelims · Environment & Ecology · Air, Marine, Noise and Other Pollution
At a Glance
- Big spills Exxon Valdez, Deepwater Horizon
- Indian spills Mumbai 2010, Ennore 2017
- Microplastics Below 5 mm
- Garbage patch Great Pacific
- Indian rules PWM Rules 2016
- Exam link UPSC Prelims, Environment & Ecology: Air, Marine, Noise and Other Pollution
Where Does It Fit?
This topic follows dead zones and acidification and covers physical and chemical contamination of the sea by oil and litter. It leads to the Coastal Regulation Zone rules. Previous topic: Dead Zones and Ocean Acidification. Next topic: Coastal Regulation Zone (CRZ) Notification, 2011.
What Are the Key Facts on Oil Spills?
| Aspect | Details |
|---|---|
| Causes | Tanker accidents, collisions, groundings, blowouts at offshore wells, pipeline leaks and illegal washing of tanks |
| Effects | Oil coats birds and mammals, smothers intertidal life, harms fisheries, mangroves and reefs, and toxic compounds persist |
| Exxon Valdez (1989) | Alaska tanker spill that polluted hundreds of kilometres of coast |
| Deepwater Horizon (2010) | Gulf of Mexico well blowout, one of the largest marine oil spills in history |
| Indian cases | Mumbai 2010 collision of MSC Chitra and MV Khalijia-3; Ennore creek 2017 after collision of two vessels |
| Response tools | Booms to contain, skimmers to collect, dispersants to break up oil, in-situ burning and bioremediation by oil-eating bacteria |
| Legal frame | MARPOL, OPRC Convention and the National Oil Spill Disaster Contingency Plan; Coast Guard leads response in India |
What Are Ocean Trash and Microplastics?
- Marine debris: waste in the sea, most of it plastic
- Sources: land litter, rivers, fishing gear, shipping and storms
- Gyres: circular currents concentrate waste, as in the Great Pacific Garbage Patch
- Microplastics: particles below 5 mm: primary (microbeads, pellets, fibres) and secondary (fragments)
- Effects: entanglement, ingestion, blocked guts, toxins carried by plastic, spread of species on floating debris
- Food chain: microplastics have been found in plankton, fish, salt and human samples
- Ghost nets: lost fishing gear traps animals for years
- India: Plastic Waste Management Rules, 2016, extended producer responsibility and ban on identified single-use plastics from 1 July 2022
What Else Should You Remember?
- Spill fate: oil spreads, evaporates, emulsifies, disperses and sinks over time
- Crude oil: a mixture of hydrocarbons with different toxicity
- Sheen and slick: thin layers of oil on the sea surface
- Tar balls: weathered lumps of oil washing up on beaches
- Dispersants: chemicals that break oil into droplets, which can themselves be toxic
- Boom: a floating barrier to contain oil
- Skimmer: device that removes oil from the surface
- In-situ burning: controlled burning of oil on the sea
- Torrey Canyon: 1967 tanker spill off the UK, a landmark that led to MARPOL
- Wakashio: 2020 bulk carrier grounding near Mauritius that spilled fuel oil
- Ennore spill 2017: leaked heavy fuel oil near Chennai after two vessels collided
- Mumbai 2010: spill off Mumbai harbour affected mangroves and beaches
- Oil Spill Response: Indian Coast Guard has pollution response vessels and aircraft
- Great Pacific Garbage Patch: a vast zone of floating plastic in the North Pacific gyre, with an area estimated at over a million sq km
- Plastic in the sea: millions of tonnes enter the sea each year
- Microbeads: tiny plastic beads in cosmetics, now banned in many countries
- Synthetic fibres: washing clothes releases microfibres
- Tyre wear: a large source of microplastics on land
- Biofouling and plastics: plastics carry organisms across the sea
- Plastic additives: chemicals added to plastic can leach into water
- Global Plastics Treaty: UN negotiations have been under way since 2022 for a legally binding instrument
- Clean Seas: UNEP campaign against marine litter
- Link to previous: see Dead Zones and Ocean Acidification
- Link to next: see Coastal Regulation Zone (CRZ) Notification, 2011
- Link to waste: see Waste Management macro
- Caution: spill volumes and patch sizes are estimates that vary by source
- Exam hint: remember example spills, response tools and the definition of microplastics
- Oil dispersal natural: evaporation, wave action, sunlight and microbes break down oil, but heavy fuel oil lingers
- Seabird mortality: oiled birds lose waterproofing and die of cold and poisoning
- Compensation: the International Oil Pollution Compensation Funds pay for large tanker spills
- Plastic bags and bottles: common items on Indian beaches and the main objects of clean-up drives
Why Does It Matter for the Exam?
- Microplastic size: Below 5 mm
- Response: Boom, skimmer, dispersant
- Rule: PWM Rules 2016
- Current affairs link: Plastics treaty talks
- Common errors: treating dispersants as harmless
As an analytical point, oil spills are sudden events with lasting local harm, while plastic debris is a slow and global accumulation. Preventing spills with better shipping rules and cutting single-use plastics at source is more effective than clean-up.
Why Is This Topic Important?
- Spill Sudden harm
- Trash Slow build-up
- Fix Prevent
What Came Next?
The next topic covers the Coastal Regulation Zone Notification, 2011. Next topic: Coastal Regulation Zone (CRZ) Notification, 2011.
Key People and Terms
- Oil slick Floating oil layer
- Boom Containment barrier
- Dispersant Oil-breaking chemical
- Microplastic Plastic below 5 mm
- Ghost net Lost fishing net
- Gyre Large ocean current loop
Exam Corner
Points to Remember
- Microplastics: below 5 mm.
- Exxon Valdez: 1989.
- Deepwater Horizon: 2010.
- Single-use ban from 1 July 2022.
- Coast Guard leads oil spill response.
Do Not Confuse With
- Primary and secondary microplastics Made small versus broken down
- Booms and skimmers Contain versus collect
- Marine litter and microplastics All debris versus tiny particles
Memory Hook
Spill and slick, trash and gyre, tiny plastics in our food.
Mains Angle
Questions ask for examples, response and rules. These points help.
- Spills Causes, response
- Plastics Impacts
- Rules PWM Rules
A Question You May Face
An original practice question, not a past paper question.
“Discuss the causes and effects of oil spills and plastic pollution in the oceans and the measures to address them.”
How to Answer
- Spills Causes.
- Debris Plastic.
- Effects Wildlife, food.
- Rules MARPOL, PWM.
GS Relevance
Frequently Asked Questions
What are the effects of oil spills on marine life?
Oil coats the feathers and fur of birds and mammals, destroying insulation, and is swallowed when animals clean themselves. It smothers shore life, fouls mangroves and reefs, and its toxic components poison fish and shellfish, with effects lasting years. Clean-up methods can also cause additional harm if not properly managed.
How are oil spills cleaned up?
Responders use floating booms to contain oil, skimmers to remove it from the surface, sorbent materials, chemical dispersants that break oil into droplets, controlled in-situ burning and bioremediation using oil-degrading microbes. Choice of method depends on the oil type, weather and sensitivity of the area. In India, the Coast Guard coordinates response under the National Oil Spill Disaster Contingency Plan.
What are microplastics?
Microplastics are plastic particles smaller than 5 millimetres. Primary microplastics are made small, such as microbeads and pellets, while secondary ones form when larger plastic items break down by sunlight, waves and wear. They are found in oceans, rivers, soil, air and food, and may carry toxins and enter food chains.
What is the Great Pacific Garbage Patch?
It is a huge accumulation of floating plastic debris in the North Pacific Ocean, collected by the circular currents of the North Pacific gyre. It is not a solid island but a dispersed area with plastic pieces and many microplastics, estimated to cover over a million square kilometres. It shows how ocean currents concentrate waste.
What is India doing about plastic waste?
India's Plastic Waste Management Rules, 2016, amended in 2018 and 2021-2022, set out extended producer responsibility, waste collection and standards for plastics. A ban on identified single-use plastic items began on 1 July 2022. India also took part in the UN negotiations on a global plastics treaty.
PYQ Practice — Statement Analysis
1 Microplastics are smaller than 5 mm.
Plastic particles.
2 Dispersants remove oil from the sea completely.
They only break it into droplets.
3 The Exxon Valdez spill took place in 1989.
In Alaska.
4 India banned some single-use plastics from 1 July 2022.
Identified items.
Past Mains Questions on This Topic
This topic comes under Air, Marine, Noise and Other Pollution. UPSC Mains questions asked on the matching syllabus topic, year-wise with marks:
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