Particles from common household paints can harm living organisms

The researchers also found that the new membrane exhibited strong filtering effects.

Researchers from the University of Bayreuth examined two types of standard dispersion paints and found that they contain many solid particles that are barely a few micrometers or nanometers in size.

Dispersion paints are often used in homes to paint walls and ceilings. A multidisciplinary research team from Bayreuth University Recently he examined the chemical composition of two common dispersion coatings and identified a large number of solid particles as small as a few micrometers or nanometers. It has been shown in studies on biological test systems that these particles are harmful to living organisms. These particles can be filtered out of the water before they enter the environment using a new membrane developed at the University of Bayreuth.

Dispersion Paint Components

Bayreuth’s study on dispersion coating components and their potential effects on living organisms is published in the journal Environmental Toxicology and Environmental Safety. It is based on a close interdisciplinary collaboration at the University of Bayreuth Collaborative Research Center 1357 Microplastics. The researchers chose two widely available paints often used in homes.

These primarily have drip properties as they are designed to paint walls on one side and ceiling paint on the other. The solids content of the two paints is 49 and 21% by weight, respectively, while the organic content is 57 and 7% by weight. Characteristic solid components in the micrometer or nanometer range are particles of silicon dioxide, titanium dioxide and calcium carbonate, as well as particles of various types of plastics, especially polyacrylates.

Many of these fine particles enter the environment, for example, through erosion of coatings or weathering. Our study now shows that when brushes, rollers, scrapers, and buckets used to paint walls and ceilings are cleaned by washing away paint residue, particles can end up from dispersed paints in wastewater and thus in the environment as well. The impact on the environment must be thoroughly investigated, which is all the more urgent given the worldwide prevalence of disperse paints and their diverse physical compositions. That is why we not only limited ourselves to the chemical analysis of coating components, but also investigated their effects on living organisms and cells,” says Professor Dr. Andreas Greiner, Deputy Spokesperson for the Collaborative Research Center “Microplastics”.

Effects on living organisms

For their inquiries, the Bayreuth scientists selected two test systems that have been well demonstrated in research: Daphnia magna water fleas and a series of rat cells. Daphnia tested according to OECD guidelines for testing chemicals. In this test, the movement of living things is considered. It was found that water flea mobility was significantly reduced when the water contained a high content of dissolved and undissolved inorganic plastic particles and microplastics.

In mouse cells, a decrease in cell activity was observed, which was generally caused by particles in the nanometer range. Metabolism in mouse cells is significantly disrupted by nanoparticles of titanium dioxide and plastics in particular.

“Our research shows that components of dispersed paints can cause reactions to varying degrees in organisms and cells. Therefore, the possibility that the components are harmful to the environment cannot be ruled out. More research is urgently needed in this area, especially since we still know very little about whether Interactions between plastic nanoparticles and inorganic nanoparticles could have caused additional damage,” explains Professor Dr.

“It is also a largely unresolved question about how the components of disperse paints interact with other substances in different environmental parts – for example, in air, in soil or in rivers. However, it is already clear that disperse paints should not be disposed of in the environment carelessly,” says Professor Dr. Ruth Freitag, chair of the Department of Practical Biotechnology at the University of Bayreuth.

New membrane with high filtration effects

In parallel with studies of dispersing paints and their potential effects, researchers under the direction of Prof. Dr. Andreas Greiner have focused on another project: they have developed a new process for removing potentially harmful particles of dispersing wall paints from wastewater by filtration. This involves the use of a membrane made of functional fibers produced by the electrospinning process. The membrane retains nanometer and microscopic particles in different ways.

On the other hand, the pores of the membrane are too fine to allow the passage of fine particles. On the other hand, the interactions between the membrane fibers and the nanoparticles cause them to stick to the surface of the membrane even though they fit into the pores. In both cases, the filtration effect is not associated with rapid and extensive clogging of the pores. Therefore, water, for example, can easily pass through the membrane and run off.

in the magazine Molecular materials and engineering, Bayreuth scientists describe the successful application of the membrane. They also tested two dispersal paints that proved harmful to the study organisms. As it turned out, the membrane is able to retain typical color components – in particular, nanoparticles of titanium dioxide and polyacrylate, and microparticles of calcium carbonate.

“In everyday life, all these color components are discharged together in wastewater. Here they mix and in some cases change their structures and properties due to their interactions. Therefore, we specifically tested the filtration performance of our electrode spindle membrane on these mixtures. The high filtering effects are shown What we have achieved is that this process has great potential when it comes to purifying water from particles in the micro- and nanometer scale, such as those found in paints commonly used around the world,” says Greiner.

References: “Separating the Biological Effects of Primary Nanoplastics from Additional Compounds for Dispersion Coatings” By Anne-Catherine Muller, Julian Brehm, Matthias Vollkel, Valérie Jerome, Christian Laforsh, Ruth Freitag and Andreas Greiner, July 16, 2022, Available here. Environmental Toxicology and Environmental Safety.
DOI: 10.1016 / j.ecoenv.2022.113877

“Filtration of Paint-Contaminated Water by Electrospun Membranes” by Anne-Katherine Muller, Chi Kang Shu and Andreas Greiner, July 18, 2022 Available here. Molecular materials and engineering.
DOI: 10.1002 / mame.202200238