Agricultural soils and microplastics: Are biosolids the problem?

Biosolids are the solid by-product of wastewater treatment system. They regularly applied to agricultural land in UK fertilize and increase crop yields, but they have been shown contain high concentrations microplastics. Here we sampled a selection soils Southeast England which had received or never biosolid treatment. Sites were on two occasions summer winter. Microplastic (MP) numbers both treated fields (874 MP/kg) untreated (664 wide variety polymers found across sites. However, there was lack significant difference between soils. This suggests influence other microplastic sources e.g. plastic general littering, external conditions farm management rainfall. higher suggesting that erosion, runoff, wind transport may be removing microplastics from these systems. The dynamic nature result them becoming vector for into wider environment. variability results seen here highlights complexity heterogeneous study biosolids, whilst likely contributor, not sole source Further research is required determine sink dynamics Understanding contamination imperative future mitigation strategies effective.