Microplastics

Infobox microplastics

From parks and industrial sites to forests, fields and nature reserves, microplastics are now found almost everywhere.

Microplastics are generally understood to be plastic particles < 5mm in size.

These break down into smaller and smaller particles in the environment over time. The smaller the particles, the more likely they are to be absorbed by plants and soil organisms. In addition to different types of plastic, they often contain harmful additives such as phthalates or bisphenols.

Sources of microplastics in soil can include:

Tyre and road abrasion, contaminated organic fertilisers (e.g. compost, sewage sludge), cigarette filters and plastic waste, as well as abrasion from films, fleeces, nets, plant pots and paints.

Road and tyre abrasion in Austria is estimated at more than 2 kg/person/year. In addition to rubber, reinforcements and fillers, car tyres contain various additives such as vulcanising agents, antioxidants and ozone inhibitors to improve performance and slow down ageing. However, the exact composition is a trade secret of tyre manufacturers. In particular, the so-called para-phenylenediamines (PPDs) used to combat tyre ageing have become controversial after a specific conversion product, 6PPD quinone, was found to be particularly toxic to fish.

Overall, the effects of microplastics on the environment and human health are still poorly understood. Because microplastics are very slow to degrade, their levels in soils increase over time (“accumulation”). Accumulation can have long-term effects on „soil health“ by altering soil physical properties and influencing the composition of microorganisms.