Litter Index

A litter index is a quantitative measure of marine-litter density used to assess pollution and track trends, expressed as items per square meter or per linear meter of beach, or items per unit area of seabed. Standardized protocols, including the UNEP/IOC guidelines and OSPAR beach-litter surveys, fix transect length, size classes, and material categories so results are comparable across sites and time. Under the EU Marine Strategy Framework Directive 2008/56/EC, Descriptor 10 sets marine litter as a Good Environmental Status indicator, with beach-litter abundance as a core metric. Indices feed source apportionment and the EU threshold of 20 litter items per 100 meters of coastline.