Monitoring protocols generally include a description of the survey location (e.g. shoreline, sea surface, water column, seafloor, river or biota), classification (e.g. size, function, composition), quantification (e.g. mass per unit of area, number of items per unit of area/volume), methodology for collection (e.g. trawl net), spatial scale and survey frequency. The range of monitoring programmes described can provide information for the design of strategies and actions to prevent and clean up marine litter. These include programmes that target the control of specific problematic litter items (such as single-use plastic bags or polystyrene fishing boxes), locations (e.g. areas identified as zones of accumulation, or sites from which litter is dispersed such as storm water drains), or chemicals that are POPs including some that are also plastic additives (e.g. the global monitoring plan for POPs) (Stockholm Convention 2017).
From collection: Drowning in Plastics: Marine Litter and Plastic Waste Vital Graphics