Glitter harms aquatic ecosystems, says study – 08/15/2023 – Environment

A constant presence in carnival costumes and makeup, glitter particles can compromise the growth of organisms that form the basis of aquatic ecosystems, such as cyanobacteria, which play a fundamental role in the biogeochemical cycles of water and soil and in feeding other organisms .

The conclusion is from a study by the University of São Paulo (USP) recently published in the journal aquatic toxicology.

Also known as glitter, glitter particles are microplastics smaller than 5 millimeters. Their reduced size prevents them from being filtered by the sewage treatment network. So when revelers shower, they run straight down the drain and spread across beaches, sediments, forests, lakes and oceans.

It is estimated that, in recent years, more than 8 million tons of the material were released into the ocean, according to current scientific literature.

As it is not biodegradable, glitter comes into contact with aquatic organisms and affects the entire ecosystem around it. This exposure can happen in a variety of ways, such as ingestion, contact with toxic by-products, or damage and injury caused by the sharp edges of the particles. In addition, its shape, size and physical-chemical properties make it difficult to accurately measure water contamination levels.

In a study conducted at the Center for Nuclear Energy in Agriculture at USP (Cena-USP) with support from FAPESP, researchers evaluated the effects of five concentrations of non-biodegradable glitter particles on two strains of cyanobacteria, Microcystis aeruginosa CENA508 (unicellular) and nodularia spumigena CENA596 (filamentous), which are responsible for formations of blooms in water bodies. Both are part of the collection of nearly 800 strains collected in the country by the Cyanos group.

During 21 days, the cell growth rate of the cyanobacteria was measured every three days by means of spectrophotometry (optical density measurement).

“We were able to observe that increasing doses of glitter increase the biovolume of cyanobacterial cells, causing them to undergo stress processes that even compromise photosynthesis, which highlights the little-explored toxicity of glitter in microorganisms”, says Mauricio Junior Machado, author of the study and researcher at the Laboratory of Cellular and Molecular Biology at Cena-USP.

“It’s worth remembering that if something affects cyanobacteria directly, then indirectly it will affect other organisms in the same environment.”

The results suggest that ambient glitter concentrations similar to the highest dosage tested (>200 mg of glitter per liter of water) may negatively influence susceptible organisms in aquatic ecosystems.

The most evident effect was seen in Microcystis aeruginosawhich showed changes in growth rate throughout the experiment period: a growth peak was recorded in the glitter treatment of 50 mg per liter of water, while the lowest growth was recorded with 200 mg per liter of water.

In nodularia spumigena, the greatest growth was measured at 100 mg glitter per liter of water, with negative effects seen at glitter concentrations above 137.5 mg per liter of water, affecting cell density without recovery. The difference in the growth rate only happened on the 21st day of the experiment.

There was no significant difference between chlorophyll and total carotenoid concentrations. However, in absolute values, both strains showed a reduction in carotenoids in the groups exposed to 200 and 350 mg of glitter per liter of water, and a variation in chlorophyll fluorescence was observed in nodularia spumigena for cells exposed to 350 mg per liter of water.

sustainable carnival

The researchers believe that the study offers a basis for the government and the population to rethink the celebrations of the most popular party in the country and encourage a more conscious consumption of items derived from plastic.

“Glitter was created to be used in festivities and, at those times, people end up not thinking about the problems created for the environment”, believes Marli de Fátima Fiore, researcher at Cena-USP and coordinator of the work.

“But we must remember that these microplastics compromise and contaminate both marine and freshwater ecosystems, which are extremely important for our lives, and think about campaigns so that they are avoided as much as possible.”

The researchers now intend to carry out the same tests on more strains of cyanobacteria and also analyze the so-called biodegradable glitter to verify whether this material really does not cause problems for the organisms (such as, for example, damage resulting from possible pigments with metals in the composition).

The article Response of two cyanobacterial strains to non-biodegradable glitter particles can be read at: www.sciencedirect.com/science/article/abs/pii/S0166445X23001935?via%3Dihub.