Soil Metabolome Impacts the Formation of the Eco-corona and Adsorption Processes on Microplastic Surfaces

This study shows that soil metabolitesfrom different soilsform an eco-corona of similar composition on microplastics, whichacts as a barrier, inhibiting the adsorption of other metabolitesand organic contaminants. The eco-corona onmicroplastics refers to the initial layer ofbiomolecular compounds adsorbed onto the surface after environmentalexposure. The formation and composition of the eco-corona in soilshave attracted relatively little attention; however, the eco-coronahas important implications for the fate and impacts of microplasticsand co-occurring chemical contaminants. Here, it was demonstratedthat the formation of the eco-corona on polyethylene microplasticsexposed to water-extractable soil metabolites (WESMs) occurs quiterapidly via two pathways: direct adsorption of metabolites on microplasticsand bridging interactions mediated by macromolecules. The main eco-coronacomponents were common across all soils and microplastics tested andwere identified as lipids and lipid-like molecules, phenylpropanoidsand polyketides, nucleosides, nucleotides, and their analogues. WESMswere found to reduce the adsorption of co-occurring organic contaminantsto microplastics by two pathways: reduced adsorption to the eco-coronasurface and co-solubilization in the surrounding water. These impactsfrom the eco-corona and the soil metabolome should be considered withinfate and risk assessments of microplastics and co-occurring contaminants.

Automated summary

This study found that soil metabolites from different soils create a similar eco-corona on microplastics, acting as a barrier that inhibits the adsorption of other metabolites and organic contaminants. The formation and composition of the eco-corona in soils have not received much attention, but it has significant implications for the fate and impacts of microplastics and co-occurring chemical contaminants.