The UN negotiations on a global plastics agreement on 15.08.2025 have remained without result. The negative impact of plastic in aquatic ecosystems has been observed in science and the public for some time. From images of plastic whirlpools in the ocean to finds of microplastics in marine life. The discussion regarding the consequences for plants, animals and humans is omnipresent. Due to the so-called “glitter ban” from the EU, this discussion has just gained new momentum. According to this, since October 15, 2023, no more microplastic-containing cosmetics such as glitter or scrubs may be sold.
But plastic can now also be found in our agricultural soils. NABU estimates that the total plastic emissions in agricultural soils are at least 19,055 tonnes per year, of which about 19% can be attributed to the agricultural sector itself. The majority of this, just under 70%, is introduced into the soil through components in fertilisers. The rest is generated by soil improvement, pesticides and seeds, as well as plastics in fodder cultivation, plant aids and containers and irrigation systems.
The remaining 81% of total emissions are not attributed to agriculture, although just over half of them are caused by the spreading of sewage sludge, a practice that is the responsibility of agriculture. A further 38% is due to littering. The remaining 8% is caused by misthrows into composts.
While the consequences of plastics in oceans and rivers are being intensively researched, the consideration in terrestrial ecosystems is still incomplete. According to current knowledge, however, the influence of plastics can already be roughly estimated.
Plastics in the soil can change the physical properties such as storage density, pore volume and water content of soils and thus have an influence on its ecosystem function. The influence essentially depends on the size of the plastic particles. For example, small particles can result in better soil aeration and larger plastic fibres can lead to channel formation, i.e. increased water transport and thus drying out of the soil. Studies also show an influence on the pH value and a change in the chemical properties of the soil due to the washing out of additives and plastics. As has already been observed in water bodies, microplastics accumulate pollutants on the surface and could thus also lead to increased pollutant transport in soil and groundwater. More detailed research in this regard is still pending.
In addition to this indirect toxicity caused by pollutants, direct toxicity must also be assumed. For example, the particles can cause damage to tissues and membranes of organisms. Nanoparticles pose a particular risk here, as they pass through cell walls due to their small size of 50-100 nm and can be absorbed by plant roots. The respective effect depends on the type of plastic.
Larger soil organisms such as earthworms and other animals in the soil also absorb microplastics directly or through the food chain. There are indications of impairment of vitality, enzyme activity as well as the growth and immune system of the organisms. An influence on humans through the consumption of contaminated plants or animal products contaminated by animal feed is conceivable and requires further research.
To reduce plastic emissions, educational initiatives in agriculture are needed to increase the recycling rate or replace conventional plastics with more degradable materials. There is also a need for the development of suitable measurement methods for checking the respective soil load. The law can also impose further requirements and tighten the limit values for plastics as foreign components, as well as limit the degradation time for plastic applications in the environment. NABU is also calling for a limitation of sewage sludge application.
Further information can be found in the report by the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT and Ökopol on behalf of the German Nature and Biodiversity Conservation Union (NABU).
In any case, plastics in soils are a burden on our ecosystem that has received too little attention so far. Therefore, the MuP Group will focus more on this area in the future in order to make a further contribution to a healthy environment. Engineering for a better tomorrow.