Negligible effects of microplastics on animal fitness and HOC bioaccumulation in earthworm Eisenia fetida in soil

Microplastics in soils: a review of possible sources, analytical methods and ecological impacts

“…The interactions of MPs with HOCs in soil further depends on the physicochemical properties of HOCs, such as hydrophobicity. 53 From these results, we can conclude that some factors affect adsorption, but more factors affecting the adsorption behavior of soil MPs should be considered.…”

“…Several studies have also shown that MPs can affect the transport of organic contaminants such as hydrophobic organic compounds (HOCs), as their sorption behavior can differ from that of organic matter and minerals in soils. However, Wang et al 53 (Table 4) suggested that MPs did not act as vectors to enhance contaminant uptake, but that the competitive sorption of MPs resulted in decreased bioavailability of HOCs in soil pore water. The biodynamic model analysis confirmed that ingestion of MPs contributed negligibly to contaminant bioaccumulation.…”

“…This result suggests that MPs and their resulting oxidative stress could damage tissues (Table 5). 53 Similarly, Song et al 68 found that MP exposure can reduce the total antioxidant capacity (T-AOC) and glutathione peroxidase (GPx) activity and elevate malondialdehyde (MDA) levels in snail liver tissues. Thus previous findings indicated that MP toxicity could be caused by oxidative damage, which has a damaging impact on soil organisms' growth as well as fitness.…”

Microplastics Effects on Reproduction and Body Length of the Soil-Dwelling Nematode Caenorhabditis elegans

“…In comparison, Rodriguez-Seijo et al (2017) observed no adverse effects on survival, reproduction, or body weight of the earthworm Eisenia andrei, but did find gut damage and histological alterations including congestion and fibrosis. Under MP exposure, the earthworm Eisenia fetida showed only marginal effects, with the anti-oxidase system negatively affected only at artificially high concentrations (Wang et al, 2019), while the isopod Porcellio scaber was not affected by MP at all (Jemec Kokalj et al, 2018). In view of our results and those from these studies, it appears that not all species or their biological endpoints are sensitive to MP, as our findings indicate that body length is a non-sensitive metric for MP toxicity in C. elegans.…”

“…One study documented histopathological damage, including congestion fibrosis and inflammatory infiltrates in earthworms in response to MP exposure, although no biological functions were affected (Rodriguez-Seijo et al, 2017). Wang et al (2019) found oxidative stress in earthworms in response to artificially high MP exposure only. Translocation of MP by earthworms (Huerta Lwanga et al, 2017a;Rillig et al, 2017b) and collembola (Maaß et al, 2017) could increase the exposure of other soil-dwelling species to MP.…”