New plant-based glitter poses no harm to soil organisms

Plastic pollution is everywhere. Each year, more than 368 million tons of plastic are produced, of which more than 13 million tons end up in the ground where it can be toxic to wildlife.

Researchers are particularly concerned about the environmental impacts of “microplastics,” which are small plastic particles measuring less than 5 mm.

Microplastics can be produced from products like glitter or when larger objects, including water bottles, break down into smaller and smaller pieces once in the environment.

Due to their small size, animals can eat microplastics, mistaking them for food, which can cause starvation and malnutrition as well as abrasions to the gastrointestinal tract.

Much research has shown that microplastics are toxic to ocean species, but far fewer studies have investigated their impacts on terrestrial species. This is despite the fact that annual releases of plastic onto land are estimated at more than four times the level that enters the oceans.

Glitter is a type of microplastic used in cosmetics, clothing or for decorative purposes.

Most glitter is made of a plastic called polyethylene terephthalate, which you probably know as PET. It’s the same plastic used for water bottles and soda containers.

Conventional glitter also often contains aluminum or other metals, which is where the sparkle comes from.

It’s unclear how much glitter ends up in the environment, but anyone who has ever worn glitter makeup or used glitter in arts and crafts knows that it seems to end up everywhere.

In 2023, the European Union officially banned the sale of bulk plastic glitter and certain other products containing microbeads, with the aim of reducing environmentally harmful microplastic pollution by 30% in member countries by 2030 .

So far, Australia has not followed suit.

A study in New South Wales, Australia, found that 24% of microplastics in sewage sludge were glitter.

Once glitter enters the environment, it is difficult to dispose of due to its small size and because it can become transparent over time as it loses the metal components.

Although biodegradable glitter is already commercially available, previous research indicates that these products may be just as harmful or more toxic to aquatic organisms than conventional PET glitter, as most biodegradable varieties on the market must be covered with a layer of colored aluminum and topped with a thin layer of aluminum. plastic layer.

Part of a research team based at the University of Cambridge has been working on making more durable glitter. The study is published in the journal Chemosphere.

They created a new cellulose-based nanocrystal that sparkles in light and is biodegradable. Cellulose is made from glucose and is the component that gives tree wood its strength.

They wanted to compare the potential toxicity of conventional glitter with the new cellulose flakes in tests on the durability of the new glitter.

They used a small soil creature called a springtail (Folsomia candida). Springtails are small, white, eyeless invertebrates that are closely related to insects. They are widespread in soils around the world where they feed on dead leaves and compost.

These creatures are used as an indicator of soil quality and, because they are sensitive to toxic compounds, are often used to test for the presence of potential pollutants.

Using soil from the University of Melbourne’s Dookie campus, the researchers exposed the springtails to different concentrations of conventional and cellulose flakes and studied the impact on their reproduction, survival and growth.

They found that neither glitter had any impact on the survival or size of the springtails. However, once concentrations of conventional flakes in soil reached 1,000 mg of flakes per kg of soil, springtail reproduction was reduced by 61%.

The level of contamination they studied is comparable to that of soil contaminated with microplastics. Contaminated soils have been found to contain up to around 100,000 mg per kg of microplastics, with most soils containing less than 10,000 mg per kg.

Compared to conventional flakes, there was no toxic effect on springtail reproduction, regardless of the concentration of cellulose flakes.

So while it is promising that no type of glitter is directly harmful to springtails, it is concerning that conventional glitter affects their ability to reproduce.

Fewer springtails being born can weaken their population, which could lead to more serious problems for soil health, such as decreased organic matter breakdown and fewer nutrients released to plants.

Researchers suggest thinking twice before using conventional glitter in makeup, clothing or for arts and crafts, but hope people will soon be able to buy a safer, more durable and equally sparkly alternative.