In News:

A first-of-its-kind comprehensive study has detected inhalable microplastics in the ambient air of major Indian cities, uncovering a largely ignored dimension of urban air pollution. The research monitored air samples from densely populated market areas across Delhi, Mumbai, Kolkata, and Chennai, highlighting a regulatory blind spot in current air quality assessment systems.

What are Inhalable Microplastics?

• Definition: Tiny airborne plastic particles smaller than 10 micrometres (µm) that can remain suspended in air and be inhaled deep into the lungs.
• Unlike larger microplastics that settle quickly, these particles persist in the atmosphere due to low gravitational settling velocity.
• They are now emerging as airborne contaminants, alongside conventional pollutants such as PM?.? and PM??, sulphur dioxide (SO?), nitrogen dioxide (NO?), carbon monoxide (CO), ozone (O?), lead (Pb), and ammonia (NH?).

Sources of Inhalable Microplastics

• Tyre and brake wear from road transport
• Synthetic clothing fibres (polyester, nylon)
• Plastic packaging and urban waste mismanagement
• Paints, cosmetics, and open waste burning

Key Findings of the Study

• New Air Pollutant Identified: Inhalable microplastics are not adequately captured by existing Air Quality Index (AQI) frameworks.
• City-wise Variation: Levels were significantly higher in Delhi and Kolkata compared to Mumbai and Chennai, attributed to:
  • Coastal dispersion of pollutants in Mumbai and Chennai
  • Higher population density and poorer waste management in Delhi and Kolkata
• High Human Exposure: Urban residents inhale approximately 132 micrograms (µg) of microplastics daily, indicating chronic exposure at breathing height.
• Carrier of Toxins: These particles act as “Trojan horses,” transporting:
  • Heavy metals (lead, cadmium)
  • Endocrine-disrupting chemicals (phthalates)
• Health Risks:
  • Deep lung penetration leading to respiratory disorders
  • Increased risk of hormonal imbalance, cancer, and long-term lung damage
  • Ability to carry microbes such as Aspergillus fumigatus, including antibiotic-resistance genes, raising concerns over drug-resistant respiratory infections

Microplastics: Background

• Definition: Plastic particles <5 mm in size; particles <100 nanometres are termed nanoplastics.
• Formation: Fragmentation of larger plastics due to UV radiation, heat, wind, waves, and mechanical abrasion.
• Types:
  • Primary microplastics: Intentionally manufactured (microbeads in cosmetics, plastic pellets, synthetic fibres).
  • Secondary microplastics: Formed from degradation of larger plastic items (bags, bottles, packaging, fishing nets).

Major Sources

• Synthetic textiles
• Road transport (tyre wear)
• Single-use plastics
• Personal care products
• Ineffective plastic waste management

Regulatory Measures in India

• Ban on single-use plastics
• India Plastics Pact
• Plastic Waste Management (Amendment) Rules, 2024

In News:

A first-of-its-kind study, commissioned by the Delhi government and conducted by The Energy and Resources Institute (TERI), has revealed the presence of microplastics in groundwater across all 11 districts of Delhi. The interim findings, submitted in November 2024, also reported microplastics in Yamuna River water and soil samples along its banks.

Key Findings:

• Widespread Contamination: Microplastics were found in groundwater samples across Delhi, indicating potential contamination due to leaching from the Yamuna River.
• Additional Contamination: Microplastics were also detected in the Yamuna's water and riverbank soil, suggesting environmental pervasiveness.
• Water Usage Impact: Since Delhi relies on borewells and treated groundwater for drinking and domestic purposes, this contamination raises serious public health concerns.
• No Objection by Authorities: The Delhi government has not disputed the study’s interim findings; further post-monsoon analysis is underway, and a final report is expected later in 2025.

What Are Microplastics?

According to the UN Environment Programme (UNEP):

• Definition: Plastic particles less than 5 mm in size
• Types:
  • Primary Microplastics: Manufactured for use in cosmetics (e.g., microbeads) and textiles (e.g., microfibers from clothing, nets)
  • Secondary Microplastics: Result from breakdown of larger plastics (e.g., bottles) due to sunlight, abrasion, and ocean waves

Environmental & Health Impacts:

• Persistence: Microplastics are non-biodegradable, mobile, and difficult to eliminate from natural ecosystems.
• Toxicity:
  • Can adsorb harmful chemicals, making them more toxic
  • Known to bioaccumulate in aquatic food chains
• Human Exposure: Microplastics can enter the human body via:
  • Inhalation (air)
  • Ingestion (water and seafood)
  • Dermal absorption (through skin)
• Health Risks (UNEP Report – From Pollution to Solution, 2021):
  • Potential effects on genetics, brain development, respiration, and placental health in newborns
  • No global standard exists for safe microplastic limits in drinking water

Why is it in the News?

Recently, scientists have created plant-based plastic that doesn't create cancer-causing microplastics because 97% of it breaks down in the environment.

What is Microplastics?

• Microplastics are small plastic particles measuring less than 5 millimeters in diameter.
• These particles, which are distinguished from larger "macroplastics" like bottles and bags, stem from both commercial product development and the breakdown of larger plastics.
• Microplastics are commonly found in a variety of products, including cosmetics, synthetic clothing, plastic bags, and bottles.
• Unfortunately, many of these products can easily enter the environment as waste.
• Composed of carbon and hydrogen atoms linked in polymer chains, microplastics often contain additional chemicals such as phthalates, polybrominated diphenyl ethers (PBDEs), and tetrabromobisphenol A (TBBPA).
• There are two categories of microplastics: primary and secondary.
  • Primary microplastics are intentionally designed for commercial use, including in cosmetics and microfibers shed from textiles like clothing and fishing nets.
  • Secondary microplastics, on the other hand, result from larger plastic items breaking down due to environmental factors such as sunlight and ocean waves.
• Understanding the sources and types of microplastics is crucial for addressing their impact on the environment, wildlife, and human health, ultimately promoting more sustainable production and waste management practices.

Environmental Impacts of Microplastics:

• Microplastics pose significant environmental concerns due to their resistance to breaking down into harmless compounds, much like larger plastic items.
  • Consequently, both primary and secondary microplastics accumulate and endure once introduced into the environment.
• In marine ecosystems, microplastics have the potential to amalgamate with harmful chemicals before being consumed by marine organisms.
  • Despite efforts, conventional water treatment facilities struggle to completely eliminate microplastics from water sources.
• Additionally, microplastics contribute to air pollution as they are present in dust and airborne fibrous particles, further highlighting their pervasive impact on various environmental systems.