Most research on plastic pollution has focused on plastics entering our marine and freshwater systems. Plastic pollution to soil is an issue that has come to the attention of researchers only in recent years. A 2017 review from UK CEH illustrates that the volume of plastic and microplastic contamination of soils is likely to be as great, if not greater, than plastics entering watercourses.
Plastics accumulating in soils can have a negative effect on soil health, fertility, microbial activity and plant growth. It has been demonstrated that plastic particles can change soil properties such as soil aggregate structure, water holding capacity, and microbial diversity and functioning. Plastics entering our soils are broken down into microplastics and so have the potential to enter the food chain through plant root systems and animal grazing - which may in turn have disruptive impacts on human endocrine systems.
There are multiple sources of plastic contamination to soils including the use of plastics in farm practices, spreading of compost and digestate onto land, and plastics entering soil systems through littering and domestic activities.
The SSA has developed a Briefing Note alongside the Bio-based and Biodegradable Industries Association (BBIA), setting out the issues associated with plastic contamination to soils and proposing solutions using existing alternatives and systems that can avoid much of this contamination.
The Briefing Note calls for:
- Government to verify the feasibility of mandating the use of soil biodegradable film mulch and bale wraps.
- Defra to include the obligation for the collection of food and garden waste for treatment in composting and anaerobic digestion to be with certified compostable bin liners.
- Government to investigate the feasibility of mandating the installation of microplastic filters on all washing machines sold in the UK post.