While water treatment plants effectively remove microplastics from influent water, microplastics get concentrated in the sludge. This sewage is subsequently spread in agricultural soils for crop production. Sewage sludge can supply a large part of the nitrogen or phosphorus that most crops need. It's also a good source of organic matter that can improve the water-retaining capacity and structure of soil. However, sludge contains potentially toxic elements, such as heavy metals, pathogens, antibiotics, as well as microplastics. Once in soil, microplastics could induce changes in soil fertility and also pose a potential threat to plant performance and crop productivity. The objective of this study is to review the extent of microplastics added from the sludge, the potential impacts of sludge amendment on nutrient availability and soil biota, in order to reveal the trade-off between benefits and risks of using sewage sludge from the perspective of microplastic pollutants.
Extent and impact of microplastics on soil nutrients and biota: a trade-off assessment
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