Published: 12 September 2019 at 09:07
Commonly used plastics can affect earthworms, plant growth and pH of soil
New research shows that the presence of microplastics can stunt the growth of earthworms, and even cause them to lose weight – potentially having a serious impact on the soil ecosystem.
The study, to be published in the journal Environmental Science & Technology, is the first to measure the effects of microplastics on endogeic worms, which live in the top soil.
Academics from Anglia Ruskin University (ARU) examined the impact of biodegradable polylactic acid (PLA), high-density polyethylene (HDPE), and microplastic clothing fibres (acrylic and nylon) on earthworms living in the soil as well as ryegrass sown on top.
After a period of 30 days in the presence of HDPE, which is commonly used in the production of plastic bottles and carrier bags, they found that rosy-tipped earthworms (Aporrectodea rosea) lost on average 3.1% of their weight.
In comparison, the earthworms living in control conditions, without added microplastics, saw their weight increase by 5.1% over the 30-day period.
At the same time the study found that the presence of HDPE led to a decrease in the soil pH. And soil containing PLA, a biodegradable form of plastic, led to a reduction in the shoot height of the ryegrass (Lolium perenne), while both PLA and clothing fibres led to fewer ryegrass seeds germinating.
Lead author Dr Bas Boots, Lecturer in Biology at Anglia Ruskin University (ARU), said:
Connor Russell, a graduate of the MSc Applied Wildlife Conservation course at Anglia Ruskin University (ARU) and a co-author of the study, said: