Marine dumping is the deliberate disposal of waste or other matter into the ocean. This global practice significantly impacts marine environments, encompassing both large-scale industrial waste and smaller, often illegal, disposals. Unlike accidental spills or natural phenomena, marine dumping involves the intentional placement of materials.
What Constitutes Marine Dumping
Marine dumping is defined as the intentional discard of waste into the sea from vessels, aircraft, offshore platforms, or other human-made structures. This definition also includes the deliberate disposal of these structures themselves. It differs from pollution entering the ocean through land-based runoff or accidental events like oil spills, which are governed by separate regulations.
Sources of marine dumping are diverse, originating from both sea-based and land-based activities. Waste is deliberately discharged from ships and barges, which transport materials for disposal at sea. Offshore platforms, including oil and gas rigs, also contribute. Some land-based operations may channel waste directly into marine waters, though regulations often aim to prevent this.
Common Types of Dumped Materials
A wide range of materials are deliberately dumped into the ocean, each posing distinct threats. Plastics are prevalent, from microplastics to larger single-use items like bags and bottles, which do not biodegrade quickly. Sewage sludge, the semi-solid byproduct from wastewater treatment, was historically dumped in large quantities.
Industrial waste, containing chemicals, heavy metals like cadmium, mercury, chromium, and hydrocarbons, also constitutes dumped materials. Dredge spoils, sediments removed from waterways to maintain navigation channels, represent the largest volume of legally dumped material. Historically, radioactive waste from nuclear power, medical uses, and research was dumped, though this practice is now largely banned. Discarded fishing gear, or “ghost gear,” is another persistent and harmful marine debris.
Impacts on Marine Environments
Marine dumping has widespread consequences for ocean ecosystems. A significant impact is habitat destruction, where dumped materials can smother sensitive marine habitats like coral reefs and seagrass beds. This reduces light and oxygen, necessary for marine organisms to survive. Toxic substances from industrial waste, chemicals, and contaminated dredge spoils can directly poison marine life. These toxins accumulate in organisms’ tissues, potentially moving up the food chain and affecting human health through seafood consumption.
Plastics and discarded fishing gear pose a threat, leading to entanglement and ingestion by marine animals. Animals like pelicans, seabirds, whales, dolphins, seals, and sea turtles can become trapped in nets or ingest plastic debris, causing strangulation, starvation, or internal injuries. Dumping organic waste, such as sewage sludge, alters water quality by introducing excess nutrients. This can lead to eutrophication, where an overgrowth of algae depletes oxygen, creating “dead zones” where marine life cannot survive.
International and National Regulations
The deliberate disposal of waste into the ocean is addressed by international agreements and national laws. The 1972 London Convention was one of the first global agreements to control marine pollution from dumping. This convention established a framework for regulating materials dumped at sea, requiring permits for some and prohibiting others, such as radioactive waste and persistent plastics.
The 1996 London Protocol strengthened these regulations. It adopted a “reverse list” approach, prohibiting all dumping unless explicitly permissible. Materials like dredged material, fish waste, and vessels may be considered for dumping under strict conditions and permits. National laws, such as the Marine Protection, Research, and Sanctuaries Act (MPRSA) in the United States, implement these international frameworks, regulating dumping activities within national waters. These regulations aim to control marine pollution and promote better waste management globally.