World Environment Day 2023: A glossary of terms to do with plastic pollution

#BeatPlasticPollution

Hosted by Côte d’Ivoire and supported by the Netherlands, this year’s World Environment Day campaign is aimed towards discussing and implementing solutions to the problem of plastic pollution – one of the most prescient issues of our time.

According to UN data, more than 400 million tonnes of plastic is produced every year worldwide, half of which is designed to be used only once. Of that, less than 10 per cent is recycled. Consequently, an estimated 19-23 million tonnes end up in lakes, rivers and seas annually.

Studies have found that discarded or burnt single-use plastic harms human health and biodiversity, while polluting every ecosystem from mountain tops to the ocean floor.

This year’s world environment day is a reminder that people’s actions on plastic pollution matters – steps taken by governments and businesses to tackle plastic pollution are the consequence of this action.

A glossary of terms to do with plastic pollution

The word plastic is derived from the Greek word plastikos, meaning “capable of being shaped or moulded.” It refers to a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient with their defining quality being their plasticity – the ability of a solid material to undergo permanent deformation in response to applied forces. This makes them extremely adaptable, capable of being shaped as per requirement.

Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum. However, recently, variants made from renewable materials, such as corn or cotton derivatives have also emerged.

Around 70 per cent of global plastic production is concentrated in six major polymer types – referred collectively as commodity plastics. These include: Polyethylene terephthalate or PET, High-density polyethylene or HDPE, Polyvinyl chloride or PVC, Low-density polyethylene or LDPE, Polypropylene or PP, and Polystyrene or PS. Each of these have different properties and can be identified by their resin identification code (RIC) denoted by symbols found on plastic products.

A chart showing the resin identification codes for commodity plastics. (Wikimedia Commons)

While plastics have revolutionised human civilisation – today, they are everywhere, from automobiles to toys, health devices to packaging – their adverse environmental impact has been alarming. This is primarily due to their slow decomposition rate in natural ecosystems. Decomposition rate refers to the rate at which a material breaks down into its constituent parts through chemical processes – plastics are remarkably durable in this sense. While they do crumble into smaller particles, these particles themselves do not break down into more simpler substances.

Instead, what we get are microplastics – officially defined as plastics less than five millimetres in diameter. There are two categories of microplastics. Primary microplastics are tiny particles designed for commercial use, such as in cosmetics or textiles. On the other hand, secondary microplastics are particles that are a product of the breakdown of larger plastic items due to exposure to environmental factors such as sun’s radiation or ocean’s waves.

The problem with microplastics, like all plastics, is that they do not break down easily into more harmless particles. Instead, they find their way across the planet, from the depths of the Pacific Ocean to the heights of the Himalayas. According to the most recent global estimates, an average human consumes at least 50,000 microplastic particles annually due to contamination of the food chain, potable water, and air.

The Great Pacific Garbage Patch. (Image: Wikimedia Commons)

Notably, microplastics contain a number of toxic chemicals which pose severe risks to human health. The biggest health risk associated is with the chemical BPA or Bisphenol A , which is used to harden the plastic. BPA contaminates food and drinks, causing alterations in liver function, insulin resistance, foetal development in pregnant women, the reproductive system and brain function.

The largest collection of plastics and microplastics in the ocean is in the Great Pacific Garbage Patch – a collection of marine debris in the North Pacific Ocean. Also known as the trash vortex, it is located between California and Japan, and formed due to converging ocean currents.

Every year, as plastics enter water bodies and find their way into the ocean, they show remarkable resiliency, floating around where the current takes them until they get stuck in a gyre or large circular ocean currents. The largest such gyre is in the Pacific and hence results in the collection of plastics in the region. As per estimates, the GPGP covers a surface area of 1.6 million sq km– roughly half the size of India! There are other, smaller such garbage patches in other oceans.

The GPGP comprises majorly of single-use plastics. Broadly speaking, single-use is a term which can refer to any plastic items which are either designed to be used for one time by the consumer before they are thrown away or recycled, or likely to be used in this way. Many countries, including India, have passed legislation to either ban or severely restrict their use.