This chapter provides a comprehensive overview of emerging contaminants with a particular focus on microplastics, examining their sources, transport mechanisms, environmental impacts, detection methods and mitigation strategies. Microplastics represent a complex and persistent pollutant arising from urbanization, industrialization, agriculture and consumer activities with interconnected pathways across terrestrial, aquatic and atmospheric systems. The chapter presents an integrated case study on the Thamirabarani River Punnakayal Estuary (southern Tamil Nadu, India), where riverine, estuarine and anthropogenic processes converge. Spatial analysis reveals moderate microplastic contamination with fibers and foams dominating the composition indicating major inputs from domestic wastewater and fishing activities. The most prevalent polymers identified are polyethylene and polypropylene, with urban and mid-estuarine zones acting as contamination hotspots. The chapter emphasizes a multi-matrix detection framework incorporating water, sediment and biota to provide a holistic understanding of microplastic dynamics. Advanced spectroscopic techniques, coupled with rigorous QA/QC procedures ensure reliability and reproducibility of results. The transport and fate of microplastics in the estuary follow a sequential process involving riverine inflow, dispersion, transformation, deposition, resuspension and eventual export to the sea. Finally, it outlines a multi-level mitigation strategy emphasizing prevention, interception, treatment and ecological restoration. Policy enforcement, technological innovation and community participation are highlighted as essential components of sustainable management. This framework offers a replicable model for Indian estuaries and contributes to a national strategy for monitoring and managing microplastic pollution within the broader context of emerging contaminants.