Guidelines For The Monitoring And Assessment Of Plastic Litter In The Ocean
The principle purpose of this report is to provide recommendations, advice and practical guidance, for establishing programmes to monitor and assess the distribution and abundance of plastic litter, also referred to as plastic debris, in the ocean. It is a product of the GESAMP Working Group (WG40) on ‘Sources, fate and effects of plastics and microplastics in the marine environment’, co-led by the Intergovernmental Commission on Oceanography (IOC-UNESCO) and the United Nations Environment Programme (UNEP). The report was prepared by 19 independent experts from 14 countries, with financial support from a number of agencies and national governments (Annex I). The term ‘plastic litter’ is used throughout, but is synonymous with ‘plastic debris’. In some cases the report refers to monitoring strategies and sampling protocols that have been designed for the monitoring of all forms of marine litter (i.e. processed wood, metal, textiles, glass, munitions, and plastics).
The main audience of the report is intended to be national, inter-governmental and international organisations with responsibilities for managing the social, economic and ecological consequences of land- and sea-based human-activities on the marine environment. The decision to produce these Guidelines reflects the lack of an internationally agreed methodology to report on the distribution and abundance of marine plastic litter and microplastics, a topic that is attracting increasing concern. Use of a harmonised system will benefit the development of monitoring programmes, as envisaged under UN Sustainable Development Goal indicator 14.1.1 (marine litter), and help to raise the category of this indicator from Tier 3 (‘No internationally established methodology or standards are yet available’) to Tier 2 ('Indicator is conceptually clear, has an internationally established methodology and standards are available, but data are not regularly produced by countries’) (section 3.2.2). For practical purposes the number of references provided has been kept relatively small, citing a limited number of key sources of information that, where possible, are publicly accessible and provide an entry point to more in-depth literature.
The intention is to promote a more harmonised approach to the design of sampling programmes, the selection of appropriate indicators (i.e. type of sample), the collection of samples or observations, the characterisation of sampled material, dealing with uncertainties, data analysis and reporting the results. The Guidelines cover all size ranges of plastic litter encountered in the marine environment, on shorelines, floating on the sea surface, suspended in the water column, deposited on the seabed or associated with biota (ingested/encrusted/entangled). They may be used for the monitoring of items originating from specific sources (e.g. Abandoned Lost or otherwise Discarded Fishing Gear, ALDFG) or specific items to evaluate the efficiency of dedicated reduction measure (e.g. single-use consumer plastics, sanitaryrelated items).
This document is intended to inform the establishment of national and regional field monitoring programmes. It provides links to protocols and data recording sheets that are intended be used in the field. The scope is restricted to monitoring plastic litter in the marine environment. However, many of the techniques described can be used in freshwater environments, specifically for monitoring rivers and lakes, with appropriate modification.
GESAMP recognises the benefits of sharing information and good practice, the need for capacity building, making links, access to training and collaboration among partners. The Global Partnership on Marine Litter (GPML) was set up to fulfil these functions and those interested in this topic are encouraged to take part in this initiative, which can be accessed through the Marine Litter Network.
