Money should be spent cleaning up the oceans after WWII. The pollution entering the ocean after a war is our fault. Therefore, we should spend the resources to clean up the oceans and restore them to their prewar state. Additionally, cleaning up the oceans is an investment in the future. Much of our food comes from the ocean and its habitat is an important part of the ecosystem. By cleaning up the oceans, we ensure that the ecosystem remains intact which prevents collapse of the food chain.
Some of the world’s militaries did dump their chemical weapons in deep water. After 1945, the U.S. military required that dump sites be at least 1,800 meters below the surface. But not all governments followed suit: The Soviet military, for example, unloaded an estimated 15,000 tonnes of chemical weapons in the Baltic Sea, where the deepest spot is just 459 meters down and the seafloor is less than 150 meters deep in most places—a recipe for disaster.
Humanity has been dumping Hundreds of Thousand Tonnes of Plastic in the World's oceans, these Plastics broken up by wave action into ever smaller pieces of Plastic, are eventually ingested by the inhabitants of the Oceans, in turn Mankind catches these & processes them for Food for both Animal as well as Humans.
Chemical dumping is bad, but Plastic Dumping will eventually cause mutations within a Human's body!
The oceans around the world are vast. The pollution from WWII is a very small, far-removed problem compared to the other problems that exist in the world today. We have ongoing wars around the world. These are more critical than pollution in oceans where people never go. There are also problems with landfills that we should address first.
Our oceans were poisoned badly in the aftermath of WWII, and have continued to have all sorts of damaging chemicals and materials poured into them since. However, whose responsibility is it to clean this up? Is it the main actors? The United Nations? Advocacy groups? It is so hard to pinpoint exactly where this funding should come from. My recommendation would be that it be a combination of the last two, with funding from interested donors.