First evidence of plastistone, a novel plastic rock composite, from the Maharashtra coast of India

The excessive usage of plastics has resulted in serious environmental challenges along with evidences of distinct imprint on Earth’s geological record. In this study, a plastic-rock formation- plastistone has been identified for the first time from west coast of India in the state of Maharashtra. A plastistone sample was collected from the coastal rocky shore of Diveagar beach and analyzed using microscopic and spectroscopic techniques. The identified plastistone also contained integrated microplastics along with a substantial portion of biogenic materials, such as barnacles, shells of molluscs, and foraminifera. The plastic materials identified in the plastistone were polyamide (nylon 6), polypropylene, polyethylene, and PET (polyethylene terephthalate) based on Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) and Micro-Raman spectroscopy. The source of these plastic materials was identified as fishing gear thereby highlighting concern about plastic waste generated from discarded fishing gears. The findings provide the first evidence of plastistone formations along the Maharashtra coast and emphasize the need to incorporate occurrence of such plastic-rock composites as part of coastal ecological health monitoring protocols.