Accumulation of Spherical Microplastics in Earthworms Tissues-Mapping Using Raman Microscopy

Abstract

The presence of microplastics in the environment is now becoming a challenge for many scientific disciplines. Molecular diversity and spatial migration make it difficult to find plastic-free areas. Their negative, often toxic, effects affect plants and animals to varying degrees, causing many biochemical disorders, species degradation, and population changes. This study aimed to determine the possibility of accumulation of spherical low-density polyethylene particles of 38–63 µm (38–45 µm 1.00 g/cm3, and 53–63 µm 1.00 g/cm3) with fluorescent properties in muscle tissues of the cosmopolitan earthworm species Lumbricus terrestris, exposed to plastic contained in the soil at a concentration of 0.1% dry weight for 3 months. Analysis of the tissues by Raman microscopy included the estimation of mapping area size, sampling density, accumulation time, spectra, laser line, and laser power to detect plastic in the samples effectively. Our results demonstrate the ability of low-density polyethylene microparticles to accumulate in earthworm tissues and are presented graphically for the mapping area and images with plastic detection sites marked. In addition, this article highlights the potential of using Raman microscopy for research in the field of tissue analysis.

Keywords

• microplastics
• microplastic accumulation
• earthworms
• raman microscopy