Impacts of microplastics in agricultural environments (WP2)
We are conducting toxicological tests on individual populations of terrestrial organisms using different types of MPs. Concerning soil organisms we have studied:
i) The effects of polyester (PET) fibers in two size classes on different soil invertebrates (earthworms, enchytraeids, oribatid mites, springtails and isopods);
ii)The effects and accumulation (ingestion and egestion) of polyester (PET) fibers in earthworms (Eisenia andrei);
iii) The effects of polyethylene (PE) microbeads on enchytraeid worms (Enchytraeus crypticus) and springtails (Folsomia candida);
iv) The effects of car tyre debris on soil invertebrates (earthworms, enchytraeids and springtails).
Enchytraeid worms (Enchytraeus crypticus) and springtails (Folsomia candida) were exposed to polyester fibers of two size classes via soil and via food. The shorter fibers were produced from longer fibers by milling. The length of the long fibers was 700 – 11 500 µm, of the shorter fibers 15 – 1 300 µm.
We collected evidences of both ingestion and effects on some toxicological endpoints by some of the tested organisms. We will disseminate our results through this site with greater details after they are published in peer-reviewed scientific journals.
Concerning fresh water organisms, we are studying the acute and chronic effects of fibers and tyre particles for invertebrate species with different habitat preferences and feeding strategies (Daphnia magna, Asellus aquaticus, Hyalella azteca and Lumbriculus variegatus). According to their different habitats, the test organisms were exposed to MPs in the water phase (Daphnia, Hyalella) or mixed into sediment (Asellus, Hyalella and Lumbriculus). A range of concentrations was tested, including environmental relevant concentrations (water exposure: 0, 0.00015, 0.0015, 0.015, 0.15 g/L; sediment exposure: 0, 0.002, 0.02, 0.2, 2 g/kg). For acute exposure, ingestion and immobility or mortality was assessed, while for chronic exposure also reproduction and growth were assessed. All test organisms ingested fibers and tyres, except for Daphnia which only ingested tyre debris.
We will provide more detailed results after their publication in peer-reviewed scientific journals.