Size-dependent effects of polystyrene plastic particles on the nematode Caenorhabditis elegans as related to soil physicochemical properties

• Published in: Environmental pollution (1987) Vol. 258; p. 113740
• Main Authors: Kim, Shin Woong, Kim, Dasom, Jeong, Seung-Woo, An, Youn-Joo
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.03.2020
• Subjects: Animals; Caenorhabditis elegans; Caenorhabditis elegans - drug effects; Microplastic; Microplastics - toxicity; Nanoplastic; Particle Size; Polystyrenes - toxicity; Soil Pollutants - toxicity; Soil texture; Toxicity Tests; Toxicity values; Caenorhabditis elegans; Soil texture; Nanoplastic; Toxicity values; Microplastic
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2019.113740

Plastic polymers are widely used in various applications and are thus prevalent in the environment. Over time, these polymers are slowly degraded into nano- and micro-scale particles. In this study, the free-living nematode, Caenorhabditis elegans, was exposed to polystyrene particles of two different sizes (42 and 530 nm) in both liquid and soil media. The number of offspring significantly (p < 0.05) decreased at polystyrene concentrations of 100 mg/L and 10 mg/kg in liquid and soil media, respectively. In soil media, but not liquid media, C. elegans was more sensitive to the larger particles (530 nm) than the smaller particles (42 nm), and the median effective concentration (EC50) values of the 42 and 530 nm-sized particles were found to be > 100 and 14.23 (8.91–22.72) mg/kg, respectively. We performed the same toxicity bioassay on five different field-soil samples with different physicochemical properties and found that the size-dependent effects were intensified in clay-rich soil samples. A principal component analysis showed that the bulk density, cation exchange capacity, clay content, and sand content were the dominant factors influencing the toxicity of the 530 nm-sized polystyrene particles. Therefore, we conclude that the soil composition has a significant effect on the toxicity induced by these 530 nm-sized polystyrene particles. [Display omitted] •We assessed the nano- and micro-plastic toxicity using nematode species in soil.•C. elegans showed more sensitive response in soil than in liquid.•The nematodes showed high sensitivity to larger particles than smaller ones.•The size-dependent effects were intensified in clay-rich soil samples.•We concluded that the plastic toxicity is highly linked with soil properties. Soil texture composition is strongly linked to the toxicity of polystyrene plastic particles in the soil nematode Caenorhabditis elegans.