European badger Meles meles as a biomonitor of microplastic contamination in soil

Evidence for MP transfer through the food webs offers the opportunity of using indicator taxa for monitoring terrestrial systems through non-invasive methods, such as the analysis of faecal samples. The European badger (Meles meles) is endowed with some ecological features which may make it a suitable bioindicator for soil contamination: wide distribution, earthworm-based diet, and marking habits that allow long-term monitoring. To test this hypothesis, we collected and analysed 40 badger scats (20 for each of two macrohabitats: woodland and ecotonal areas), recovering a total of 432 potential MPs. Micro-FTIR analysis allowed to identify ten anthropogenic fibers or fragments, of which eight were plastic polymers, with synthetic textile fibers being the predominant fraction. Mean MP concentration in badger scats (4.32) was four times higher than in an equivalent earthworm sample supporting the hypothesis that this mustelid may accumulate MPs. Although MP extraction from faeces involved as many steps as soil analysis - sieving, artificial digestion and separation by density -, overall, the process was less time consuming, highlighting the analysis of faecal samples as a promising non-invasive method for monitoring MP contamination.