About Microplastics
- Definition: They are defined as plastic particles up to 5 millimetres in diameter, while nanoplastics are even smaller, measuring less than 1,000 nanometres.
- Types: Primary microplastics (e.g., cosmetics, microfibers) and secondary microplastics (formed from the breakdown of larger plastics).
- Environmental entry: Through product use, abrasion, or breakdown in natural settings.
- Persistence: Microplastics are non-biodegradable, mobile, and accumulate in ecosystems.
- Impact on Organisms: It can be ingested by marine and terrestrial organisms, causing toxicity and bioaccumulation.
- Chemical risk: Microplastics can carry pollutants and toxic chemicals, further endangering ecological and human health.
How Microplastics Enter Plants
- The study demonstrated that plastic particles entered leaves via multiple pathways, primarily through surface structures such as stomata and the cuticle.
- Stomata are tiny pores formed by specialised cells on leaves that regulate gas exchange.
- The cuticle is a wax-coated protective membrane on leaf surfaces that is particularly conducive to absorbing airborne particles like microplastics.
- Once inside, microplastics moved between plant cells and could accumulate in tiny, hair-like structures called trichomes on the surface of leaves.
- These particles were also found to travel through the plant’s water and nutrient transport systems, reaching other tissues, although trichomes acted as “sinks” by trapping many external particles and thereby limiting their movement to roots.
Ecological and Health Implications
- The study highlights significant ecological and public health risks due to atmospheric plastic pollution, as micro- and nanoplastics bioaccumulate through the food chain.
- Despite these findings, the long-term impact on human health remains unclear, prompting a call for further investigation into:
- The extent of dietary exposure,
- The absorption efficiency of microplastics in the human digestive system,
- And the potential for plastic particles to reach internal organs.
