New research from Staffordshire University highlights the increasing threat of microplastics to global food production
Plastic has a role in almost every aspect of our lives, from packaging to infrastructure, to health and agriculture. However, there is growing concern over its impact on the environment. Discarded plastics contaminate important ecosystems. Pieces of plastic under 5mm long (referred to as ‘microplastics’) are of particular concern due to the physical and toxicological risks they pose to organisms. The impact of microplastics particularly on marine and freshwater ecosystems has been well documented in recent years, but little research has focused on the impact on terrestrial environments. The Staffordshire University Forensic Fibres and Microplastic Research Group (SFFMRG) are spearheading research into the scale of plastic pollution and its impact on agricultural soils around the world.
The use of plastics in agriculture has risen significantly in recent years. Microplastics in soil are estimated to take up to 300 years to completely degrade. Researchers believe that their presence changes the characteristics of the soil such as structure, water holding capacity and microbial communities and that the microplastics are partly responsible for crop-reducing effects.
The research group have been undertaking numerous studies on this topic, including an international review into the pressures of plastic pollution in rural areas. This has highlighted the need for wider analysis of terrestrial microplastics to help reduce threats to the environment, as well as public health.
Claire Gwinnett, Professor of Forensic and Environmental Science at Stafford University, said: "We know that microplastics in agricultural soils are abundant, varied, and are influenced by land use and farming activities. We know from a small number of studies that it can affect organisms living in the soil such as worms and springtails.
"Studies on the effect of microplastics on plants are even rarer but we also know that it impacts crops grown in these environments as well as livestock living there. What we need to know now is how much plastic there is and to better understand what effect this is having."
Ellie Harrison, a PhD researcher in the SFFMRG, is also conducting a series of studies on the effects of microplastics on common UK agricultural crops. She said: "Research into the impacts of microplastics in the agricultural soils conducted at Staffordshire University has shown that this pollutant can cause a decrease in germination rate and changes to seed production which could have negative consequences for food production."
Another recent study, conducted in partnership with Çukurova University in Turkey, has investigated the abundance and type of plastics derived from disposable low tunnel greenhouse plastic films and irrigation pipes in agricultural soils in Turkey.
The researchers collected 1kg soil samples from the top 5cm of the soil from 10 different locations in the Adana/Karata region in Turkey. After analysing the samples, the team found an average of 16.5 ± 2.4 pcs/kg was present. The number of micro-, meso-, macro- and megaplastics that was identified in soil where greenhouse film and irrigation piping was used, was about 47, 78, 17, and 1.2 times higher than in farmlands that did not use plastic, respectively. The researchers hope that the findings will help to guide farmers to better manage their use and disposal of plastics.
Professor Gwinnett said: "Greenhouse films and irrigation piping are products commonly used in farming and we have the same plastic uses in the UK and across Europe. Instead of being removed, these plastic products are often left in fields where they experience wear and tear and degradation from the sun which breaks these plastics down into secondary microplastics.
"Our results show that from years and years of using these plastics, microplastics are accumulating in the soil and cannot be removed."
Another study with Çukurova University is looking into farmer practices and perceptions in Turkey to identify what the barriers are to adopting preventative measures or more sustainable practices.
Staffordshire University has been conducting a similar study in the UK in partnership with the National Farmers' Union (NFU); this research looks into the amount and types of microplastic in UK agricultural soils. The research team aim to get a better understanding of the extent of microplastic pollution in farmland.
Professor Gwinnett added: "Plastic usage in the agricultural sector may have worthy benefits in the short term, but the long-term effects cannot be ignored. We hope that our growing body of research can be used to inform decision makers and kickstart real change to safeguard soil health and the future of the farming."
Journal reference:
Rezan Gündoğdu, Derya Önder, Sedat Gündoğdu, Claire Gwinnett. Plastics derived from disposable greenhouse plastic films and irrigation pipes in agricultural soils: a case study from Turkey. Environmental Science and Pollution Research, 2022; DOI: 10.1007/s11356-022-21911-6
Subscribers to CABI’s Environmental Impact resource can access over 5,000 records on the topic of microplastics.
Microplastics AND soil yields over 760 records.
Microplastics AND (“freshwater lakes” OR rivers OR streams) yields over 753 records.