THE IMPACT OF SYNTHETIC MICROFIBERS FROM LAUNDRY WASTEWATER ON SOIL INVERTEBRATE GUT MICROBIOMES AND NUTRIENT CYCLING

Abstract

Synthetic microfibers, which are artificially produced during the process of laundry, are a major concern for soils, as a considerable portion of this synthetic material is deposited in agricultural soils via irrigation of these soils using wastewater and sewage sludge or bio-sludge. Though there has been extensive research regarding marine plastic pollution in the past, recent research has been conducted to study the physiological and ecotoxicological effects of synthetic microfibers on soil invertebrates, which are ecosystem engineers and play an essential role in maintaining the structure and fertility of the soil. This study is a systematic review of ten years of research to evaluate the relationship between microfiber exposure, microbiological dysbiosis, and nutrient cycling disorders. High consumption of microplastics results in epithelial damage, obstruction of the intestine, and decreased appetite in some invertebrates, such as earthworms belonging to the family Lumbricidae and springtails belonging to the class Collembola. Microfibers are substrates for recruitment to the solid phase in the gut of these invertebrates, leading to decreased beneficial Proteobacteria and increased Firmicutes, an indicator of inflammatory stress. Decomposition of organic matter is affected if the microbiota of the gut is altered. According to recent statistical data, which goes back to 2025, it has been observed that soils containing microfibers have shown an approximate decrease of 15% in nitrogen mineralization rates and an increase in emissions of nitrous oxide. The microfibers can transfer adsorbed heavy metals and other harmful additives to the stomachs of invertebrates through a "Trojan horse" effect, which increases oxidative stress and harms DNA. According to this study, it is absolutely necessary to conduct long-term field studies to fill the gap between scientific data and actual environmental impacts, despite the presence of dose-response relationships. The mitigation measures should also include textile engineering methods to control microfiber emissions and wastewater filtration systems to maintain significant ecosystems.