Coastal Lagoon's dual role as a sink and source for microplastics: A case study from India

Coastal lagoons, acting as transitional zones, are increasingly threatened by microplastic (MP) pollution. This study investigates the spatio-seasonal distribution of MPs in Chilika Lagoon sediments to propose effective mitigation measures. MPs were extracted using density flotation and wet peroxide oxidation, followed by quantitative analysis with a stereomicroscope and qualitative analysis with micro-Fourier Transform Infrared (μ-FTIR) spectroscopy. Sediment samples revealed significantly higher MP abundance (particles kg^-1 d.w. sediment) in the dry season (262 ± 97.5) compared to the wet season (85 ± 36.6). Blue and black filaments were dominant, with Rayon and Polyester as the primary polymers. Laundry and fishing activities might be potential MP sources. The high MP levels transported to the Bay of Bengal via the lagoon inlet create a continuous sink-source cycle, threatening fishery resources. Essential solutions such as the usage of biodegradable fishing gear, gear recycling programs, and advanced filtration in household systems may mitigate MP pollution.