Microplastics Found in Italian Soil through Insects as Bioindicators

Strategic Insights -

Researchers at the Polytechnic University of Marche in Ancona, Italy, have discovered high levels of microplastics in Italian soil through an innovative method using insects as bioindicators. According to the study published in Environmental and Sustainability Indicators, 32% of Carabid beetles ingested microplastics, with the highest ingestion rates found in areas with intense human activity. The findings reveal the importance of monitoring microplastics in different environments using cost-effective and simple methods, such as using insects as bioindicators.

Key Takeaways:

  • 32% of Carabid beetles ingested microplastics in the pilot study conducted along the Conero coast in Italy.
  • The highest ingestion rates were found in areas with intense human activity, such as a stony beach subject to summer tourism.
  • Most microplastics were primarily fragments of 0.1-1 mm in size, with polyester and silicone being the most prevalent polymers.
  • Carabids were found to be effective bioindicators of microplastics contamination in soils, with a link between microplastics pollution and anthropogenic presence.
  • Monthly sampling was conducted from July to October 2022 using pitfall traps at three sites along the Conero coast, differing in the degree of human influence.
  • The study used oxidative digestion and vacuum filtration to extract microplastics from the beetles' guts and then characterized them through optical microscopy and mFT-IR spectroscopy.

Statistics:

  • 32% of Carabid beetles ingested microplastics in the pilot study.
  • 75% of beetles ingested microplastics in July at site C, a stony beach subject to intense summer tourism.
  • 87.5% of beetles ingested microplastics in August at site C.
  • 0.1-1 mm was the size range of most microplastics found in the study.
  • Polyester and silicone were the most prevalent polymers found in the microplastics.

Sources:

  • A pilot study to assess carabids (Coleoptera: Carabidae) as potential bioindicators of microplastics contamination in soils. Environmental and Sustainability Indicators, 2025,27():100729. The publisher for Environmental and Sustainability Indicators is Elsevier.
  • https://doi-org.sdpl.idm.oclc.org/10.1016/j.indic.2025.100729