Glitter is everywhere: clothing, holiday decorations, and bodily crevices that aren’t appropriate to mention. Inevitably, it’s made its way into waterways, where new research suggests it impairs the growth of key aquatic bacteria.
Some scientists have already called for glitter to be banned, as it’s made up of non-biodegradable microplastics. Too small to be filtered out during wastewater treatment, glitter has spread into rivers and oceans, its sparkly appearance a façade for the damage it can cause to aquatic life when it gets there.
The latest victim of this shimmery menace? Cyanobacteria, more commonly known as blue-green algae. A key member of aquatic ecosystems, they play a significant role in both biogeochemical processes (think nitrogen-fixing and the oxygen cycle) and food webs.
Researchers at the Center for Nuclear Energy in Agriculture in Brazil wanted to find out the precise effect of glitter on cyanobacterial growth, which in turn could provide clues as to its wider environmental impact. “Whatever affects cyanobacteria will indirectly affect other organisms in the same environment,” said Mauricio Junior Machado, first author of the study, in a statement.
Over the course of 21 days, the team monitored the growth of two different strains of cyanobacteria in five different concentrations of glitter. Every three days, they used a light-based technique, known as spectrophotometry, to measure cellular growth rates.
Both strains were negatively affected by higher concentrations of glitter, experiencing not just reductions in growth rate, but also increased cell biovolume. The latter is one way in which cells can respond to stress – a relatable feeling if you’ve ever made the mistake of giving kids access to glitter.
“We found that increasing the amount of glitter raised the biovolume of the cyanobacterial cells and boosted stress to levels that even impaired photosynthesis,” commented Machado. Like plants, cyanobacteria get their energy via photosynthesis; if this process is affected, so is their overall function. In turn, this could have a negative effect on the other elements of the environment that rely on blue-green algae.
Given the potential widespread impact on aquatic ecosystems, the researchers hope that the study will highlight to policymakers and the general public the importance of reducing glitter use and, therefore, microplastic pollution.
“Glitter is sold for use in festivities, where people spare little thought for the environmental problems it causes,” said another of the researchers, Marli de Fátima Fiore. “However, it’s necessary to bear in mind that microplastics contaminate and damage marine and freshwater ecosystems, which are extremely important to our lives, and to think about campaigns to avoid microplastic pollution as much as possible.”
The study is published in Aquatic Toxicology.