Ecotoxicological impacts of polyethylene, polystyrene and polyamide on the land snail Cantareus aspersus in a life cycle experiment

Small plastic fragments (<5 mm, i.e., microplastics, MPs) accumulate in ecosystems, resulting in increasing concerns about their toxic effects in the terrestrial environment. While studies on MPs in the soil environment are expanding, gaps in knowledge still exist regarding their effects on soil (macro)organisms. Our study aimed to measure the response of Cantareus aspersus snails to long-term exposure to 0.1, 1 and 10 % w/w polyethylene (PE), polyamide (PA) or polystyrene (PS) particles in food. Overall, a concentration-dependent decrease in snail growth was observed, as was a general trend toward earlier maturity at low and middle MP concentrations. Mild (for PS) to severe (for PE and PA) effects on reproduction were detected but without a concentration-dependent trend. The fecundity was affected mainly by PE at 1 % (-32.9 %) and by PA at 1 % (-52.59 %), and their fertility was reduced by 43.9 % and 61.3 %, respectively. This decrease was related to increased survival, suggesting trade-offs in snail energy allocation and/or endocrine regulation. This study revealed that an environmentally relevant life-cycle assessment of toxic effects allows the detection of subtle effects regarding individual responses. These effects allowed us to demonstrate differential impacts on animal health status according to the polymer used and the exposure concentration.