Efforts to stop ocean pollution span international treaties, physical cleanup operations, agricultural reform, shipping regulations, wastewater technology, and experimental biology. Between 8 and 10 million metric tons of plastic alone enter the ocean each year, accounting for roughly 80% of all marine pollution. No single solution can address a problem that large, so governments, nonprofits, and researchers are attacking it from multiple angles simultaneously.
A Global Plastic Treaty in the Works
In March 2022, the UN Environment Assembly adopted a historic resolution to develop the first legally binding international agreement on plastic pollution, covering the full life cycle of plastic from production and design through disposal. The UN Environment Programme convened an Intergovernmental Negotiating Committee (INC) to hammer out the details, and that committee has met in Uruguay, France, Kenya, Canada, South Korea, and Switzerland since late 2022.
Progress has been slow. The fifth negotiating session has been split across multiple meetings, with the most recent part held in February 2026 for purely organizational purposes, including electing new leadership after the previous chair resigned. No substantive negotiations took place at that session. The treaty remains unfinished, and the timeline for a final agreement is uncertain. If completed, it would be the first global instrument to regulate plastic at every stage, not just after it becomes waste.
Pulling Plastic Out of the Ocean
The most visible cleanup effort is The Ocean Cleanup, a nonprofit targeting the Great Pacific Garbage Patch. Its System 002 extracted over 250,000 kilograms of plastic from the patch between 2021 and 2023. The newer System 03 has already produced the project’s largest single extraction: 11,353 kilograms in one haul. But the organization estimates it would need a fleet of roughly a dozen systems operating simultaneously to clean the entire garbage patch.
Abandoned fishing gear, often called “ghost gear,” is another major target. The Global Ghost Gear Initiative brings together more than 160 member organizations, including 23 national governments, to locate and recover lost nets, traps, and lines. In one operation off the coast of Portland, Maine, the initiative and the Gulf of Maine Lobster Foundation removed a single tangled mass of gear weighing approximately 20,000 pounds. These nets continue catching and killing marine life for years after they’re lost, making recovery efforts critical even in small quantities.
Shipping Rules That Ban Dumping at Sea
International shipping is governed by MARPOL Annex V, a set of rules administered by the International Maritime Organization that more than 150 countries have signed. The annex generally prohibits all garbage discharge into the sea, with narrow exceptions for things like food waste and certain cargo residues that can’t be recovered using standard unloading methods. Any cargo residue classified as harmful to the marine environment must be brought to a port facility, not dumped overboard.
Enforcement works through port state control. When a ship docks at a foreign port, inspectors can board and examine whether the crew knows and follows anti-pollution procedures. Every ship longer than 12 meters must display placards in the crew’s working language (plus English, French, or Spanish for international vessels) explaining what can and cannot go overboard. These rules apply to everything from commercial tankers to private yachts.
Reducing Farm Runoff Before It Reaches the Sea
Not all ocean pollution is solid waste. Nitrogen and phosphorus from agricultural fertilizers wash into rivers, flow downstream, and feed massive algal blooms that deplete oxygen and create “dead zones” where marine life can’t survive. The Mississippi River/Gulf of Mexico Watershed Nutrient Task Force set a goal of reducing nitrogen and phosphorus loading by 20% by 2025 and shrinking the Gulf’s dead zone to less than 5,000 square kilometers by 2035.
Reaching those targets requires changes at every stage between the farm field and the river. On the field itself, farmers are adopting precision application, adjusting fertilizer rates based on location and year rather than applying a uniform amount. An entire industry now helps farmers determine optimal rates and build equipment that varies application across a single field. Simple practices like changing the timing of fertilizer application or accounting for the nitrogen already present in manure can also cut losses significantly.
At the edges of fields, engineers have developed systems that intercept nitrogen before it enters waterways. Bioreactors, essentially trenches filled with wood chips, break down nitrogen in drainage water. A technique called saturated riparian buffers can remove 30 to 95% of nitrogen from tile drainage. Stacking these edge-of-field systems with better in-field practices and downstream measures like restored wetlands could reduce nitrogen losses by 45% or more, according to USDA research.
Catching Microplastics at Wastewater Plants
Tiny plastic fragments shed from synthetic clothing, tires, and packaging wash down drains and into wastewater treatment plants. How much gets filtered out depends on how advanced the plant is. Primary and secondary treatment, the standard in most developed countries, removes roughly 66% of incoming microplastics. Plants with well-optimized secondary treatment can reach 88% removal, largely because plastic fragments clump together and get absorbed into the sludge used in biological treatment.
Tertiary treatment pushes efficiency to 99.9%. Membrane bioreactors, which filter water through fine membranes after biological treatment, perform best, reducing microplastic levels to a fraction of a percent of what entered the plant. The challenge is that tertiary treatment is expensive and far from universal. Many cities, especially in developing countries, lack even basic secondary treatment, meaning microplastics pass through largely untouched.
Plastic-Eating Microbes
Researchers have identified dozens of bacterial and fungal species capable of breaking down various types of plastic. Bacteria in the Bacillus and Pseudomonas families show the broadest range, degrading common plastics like polyethylene, polypropylene, and PVC. One Pseudomonas strain isolated from plastics submerged in the Bay of Bengal broke down three different plastic types. In lab conditions, Bacillus cereus and Bacillus gottheilii caused measurable weight loss in polyethylene, PET, polypropylene, and polystyrene particles over 40 days.
The most studied example is a bacterium called Ideonella sakaiensis, which produces two enzymes that efficiently break PET (the plastic used in water bottles) into its original chemical building blocks, both of which are environmentally harmless. Marine communities of multiple bacterial species working together have also shown the ability to colonize and degrade PET and polyethylene. A marine fungus, Zalerion maritimum, can break down polyethylene as well.
The practical limitation is speed. These organisms work slowly compared to the rate at which plastic enters the ocean, and scaling biological degradation from a lab dish to open water remains an unsolved engineering problem. For now, microbial approaches are more promising for controlled settings like waste processing facilities than for cleaning up the open sea.