Marine plastic pollution and bioplastic alternatives: a review

Abstract Marine environments are polluted by plastics debris originating from land sources and from plastics used in maritime sectors such as fisheries and aquaculture, shipping, and offshore energy infrastructures. Here we review marine plastic pollution with emphasis on plastic sources, socioeconomic impact on marine industries, regulations, circular economy, and the use of bioplastics to mitigate pollution. Marine pollution sources include fisheries, aquaculture, shipping, boat industries, tourism, offshore energy plants, and artificial reefs. Fisheries and aquaculture use about 2.1 million tons of plastic annually and contribute approximately 18% of marine-based plastic pollution, primarily through lost, abandoned, or discarded fishing gear. Maritime transport contributes to plastic pollution through waste discharge, accidental container losses, and emissions from paint coatings. Marine coatings alone account for approximately 3.7% of primary microplastics entering the ocean. Coastal and marine tourism, and cruise ships generate plastic pollution via single-use plastic waste and greywater release. Artificial reefs generate plastic pollution via weathering of underwater structures. The use of bioplastics in marine and coastal tourism is increasing, particularly for single-use packaging. Bioplastics are being tested in prototype gear and nets. Nonetheless, there are limitations in the use of bioplastics because some of them are not or hardly biodegradable, some of them are not biobased, and bioplastic-derived microplastics have been detected in marine environments and biota with ecotoxicological effects comparable to those of conventional microplastics.