As he went through the North Pacific Ocean Garbage Patch in 1997, Charles Moore said that “humanity’s plastic footprint is probably more dangerous than its carbon footprint.” Despite thousands of scientific studies and numerous presentations about the detrimental effects of plastic pollution, the phenomenon is not yet fully understood. Plasticity can be a threat to organisms or toxicity, or It could be a medium of transporting other contaminants, whether intentional or otherwise. If cared for properly, plastics should not enter the environment.
However, in agriculture, used plastics remain and contaminate the soil if organic fertilizers are applied. Plastics evolved to become the most cost-effective way to sustain high crop yield over time. In other words, plastics can be used as mulch or to raise the soil temperature and decrease water consumption.
Wageningen University scientists Professor Violette Geissen, Dr. Esperanza Huerta Lwanga, Nicolas Beriot, and Benjamin van Schothorst examined two contrasting farming systems in European environments. They used soil, plant, and water samples to learn about microplastic contamination in their environments and then analyzed organic compost in the Netherlands and plastic mulch in Murcia, Spain, in the long term. After collecting samples from fields, they analyzed microplastics in the samples visually and with imaging technology. The study is now published in the journal, Environments.
Professor Geissen and her colleagues discovered microplastics in all soil samples. Still, municipal organic waste is more likely to be contaminated with plastic than compost made from greenhouse green cuttings, which was anticipated. The volume of organic material in green cuttings is more extensive than that in municipal organic waste due to plastic packaging.
The study shows the necessity that plastic pollution needs to be measured and controlled, primarily because of the risks it poses to agricultural soils. Plastic mulch can be used; however, a quality control programme for the microplastic content in soil needs to be set up. Similarly, the plastic in composts should be kept at a low level with optimal or maximum threshold values. It will require additional research on the effects and in the ecosystem to set those values.
In summary, this study confirms the omnipresence of microplastic contamination in agricultural soils. These findings show the importance of research into the environmental effects of microplastics and demonstrate the importance of continuous monitoring to keep it under control.
van Schothorst B, Beriot N, Huerta Lwanga E, Geissen V. Sources of Light Density Microplastic Related to Two Agricultural Practices: The Use of Compost and Plastic Mulch. Environments. 2021; 8(4):36. https://doi.org/10.3390/environments8040036
Main photo credit: Bo Eide Flickr