Ecological Risks of Microplastics 

Syllabus: GS3/Environment

Context

• A recent study found that Chennai’s beaches have fewer microplastics than many global counterparts  yet the risk to marine life remains significant.

What are Microplastics?

• Definition: Microplastics are tiny plastic particles or fibres smaller than 5 millimetres, many of which are invisible to the human eye.
• Scale of Pollution: Around 2.7 million tonnes of microplastics entered the environment in 2020, and this figure is projected to double by 2040, indicating a rapidly growing environmental threat.
• Forms of Microplastics: They come in various forms, such as beads, fragments, pellets, film, foam, and fibers.
• Types of Microplastics: 
  • Primary: Manufactured small on purpose (e.g. microbeads in cosmetics).
  • Secondary: Result from breakdown of larger plastic items (e.g. bottles, bags).

Why does low abundance not mean low risk?

• Toxic fibres: Nylon microfibres are highly toxic and persistent, accounting for nearly 35% of ocean microplastics.
• Pollutant carriers: Absorb toxins up to 10⁵–10⁶ times higher than surrounding water (heavy metals, POPs).
• Food chain transfer: Microplastics move through the food chain—from plankton to fish to humans—leading to biomagnification and increased health risks.

Sources

• Fishing activities: At least 10% of marine litter is estimated to be made up of fishing waste, which means that between 500,000 and 1 million tons of fishing gear are entering the ocean every year.
• Synthetic textiles: Synthetic clothes contribute 35% to microplastics burden in oceans.
• Tourism and beach use: Coastal tourism generates high volumes of single-use plastic waste, a major contributor to marine litter.
• Urban sewage and runoff: Wastewater is a key pathway; treatment plants can remove up to 90%, but the remaining still releases billions of microplastic particles daily into water bodies.

Impact/Challenges

• Human Health Concerns: Microplastics have been found in human tissue and in human blood, where their effects are largely unknown.
• Threat to Marine Biodiversity: Microplastics have been recorded in 1300+ marine species, contributing to biodiversity loss and ecosystem imbalance.
• Ingestion and Physical Damage: Marine organisms (fish, corals, plankton) ingest microplastics, causing internal injuries and blockages.
  • Over 90% of seabirds are estimated to have ingested plastic at some point.
• Disruption of Ocean Carbon Cycle: Microplastics can disrupt the carbon cycle of the oceans. If zooplanktons consume microplastics, their faecal pellets sink at a much slower rate, which means they are more likely to break apart or be eaten by other animals — “making it less likely that the carbon will reach the seafloor and become permanently sequestered”.

Initiatives to Address Microplastics

• India
  • Ban on Single-Use Plastics (2022): India prohibited identified single-use plastic items to reduce plastic waste at source.
  • Extended Producer Responsibility (EPR): Makes producers responsible for the collection, recycling, and environmentally sound disposal of plastic waste.
  • Monitoring by NCCR: The National Centre for Coastal Research monitors microplastics along India’s coasts, providing data for policy action.
• Global
  • MARPOL Convention: The International Maritime Organization framework regulates and prevents marine pollution from ships, including plastic waste.
  • Global Plastics Treaty: Negotiated under the United Nations Environment Programme, it aims to end plastic pollution by 2040 through a legally binding global agreement.

Conclusion 

• Microplastic pollution is a growing environmental and health concern, affecting water, marine life, and food chains globally.
• Addressing it requires strengthening research, promoting biodegradable alternatives, improving waste management, and enhancing public awareness.

Source: TH