The International Convention for the Prevention of Pollution from Ships, 1973 as modified by the Protocol 1978 relating thereto (MARPOL Convention) is the most important global treaty for the prevention of pollution from the operation of ships. The convention currently includes six technical Annexes, in particular Annex V dealing with different types of garbage from ships that prohibits disposal of all plastics and requires parties to provide reception facilities for the disposal of the wastes.

The Convention on the Prevention of Marine Pollution by Dumping of Wastes and other Matters (London Convention 1972) is an international treaty limiting the discharge of wastes that are generated on land and disposed of at sea.  In particular, plastics and other persistent synthetic materials are prohibited for dumping. The 1996 Protocol is a separate agreement that modernized and updated the London Convention. The protocol entered into force in March 2006 and will eventually replace the London Convention.

Basel Convention on the Transboundary Movements of Hazardous Wastes and their Disposal (Basel Convention) is the world’s most comprehensive environmental agreement for controlling the transboundary movements of hazardous wastes. It also developed the criteria for “environmentally sound management” of hazardous and other wastes. Any hazardous marine litter from land-based sources would fall under the scope of the Convention. Some non-hazardous marine litter could be considered as wastes requiring special consideration.

The Global Programme of Action (GPA) for the Protection of the Marine Environment from Land-based Activities, adopted in 1995, identified nine pollutant source categories and marine litter is one of them. In an introduction to the marine litter problem provided at the GPA Clearing-House Mechanism website, examples are given of possible national, regional and international actions.