Microplastics in paint

Does paint cause a problem to the marine environment?

Industrial paints are strictly controlled to ensure no waste enters the sewerage system.  For decorative paints, a very small percentage (estimated at 1% of decorative paint by the OECD) may be washed into the sewerage system when consumers/decorators wash their brushes / rollers.

Based on the definition of microplastics from the European Union, have estimated the microplastic content in paint to be 0.4% by volume. Microplastics are added to some paints to optimize the opacity of the pigments, improve the hardness and provide greater durability and scratch resistance.

The following table shows the emissions of microplastics from the UK decorative paint industry to the marine environment, based on the definitions above.

All figures in tonnes:

Several reports, such as the EA report, have vastly over-estimated the contribution of paints to the problem of micro-plastic pollution in the marine environment.

Microplastics originating from secondary paint related sources

These are predominantly assumed to originate from wear, tear and maintenance of paints and coatings, such as anti-fouling paints on ships and boats, high performance coatings on bridges, exterior building paints and road marking paints.  These could be leached into water courses, or through sanding preparation debris. 

In marine harbours, residues from boat hull preparation are controlled and restricted including the physical capture of the debris. BCF have a campaign to educate boat owners called the Protect Collect and Dispose Antifouling Initiative. The aim of the campaign is to work to prevent release of materials to the environment.

Road marking paints are essential for the safety of road users and in communicating messages to road users. These types of coatings are worn down over time through abrasion and weather conditions, and may end up in the watercourse. 

Paints applied to the outside of buildings, such as masonry paints, are attacked by the weather and a small percentage may be washed off into the environment. However, the vast majority of this will not reach water courses.   These coatings provide building exteriors with protection and decoration and without these properties, buildings would deteriorate.

In each case, the beneficial protective effects of the paint or coating are important to society and best practices are followed to minimise the contamination of water courses by paint and coating products.