Many years of human turbulent activity have changed our planet beyond recognition, and the degree of these changes is progressing more and more due to rapid technological development. Studies conducted over the past few years by specialists from the American National Center for Environmental Analysis and Synthesis have shown that 40% of the world's oceans have changed under the influence of humans, and not for the better. Scientists analyzed 17 different areas of activity that significantly affect the pollution of the oceans - radioactive waste, greenhouse gases, shipping, etc., as well as taking into account chemical factors - oil, fertilizers, metals, etc.
Their conclusions are disappointing. As it turned out, the most polluted areas of the ocean are the seas: Norwegian, Northern, South China and East China. This is due to the fact that a lot of oil platforms are concentrated in their waters, fishing is actively conducted, and heavily polluted rivers flow here. Both the Mediterranean and the Sea of Japan, as well as the coastal waters of the eastern United States, are not much cleaner. Here, coastlines are densely populated and there are many shipping lanes.
Of course, there are parts of the ocean on Earth that have not experienced human influence, but only 3% of the entire world’s water remains. They are located near the poles.
Let us consider in more detail the various sources that most affect the pollution of the oceans.
One of the main ones is oil that enters world waters with the ballast or drain waters of tankers or leaks during its production and transportation. Each year, the ocean is replenished with 10 million tons of oil. Oil film has already covered 20% of the global water area.
The radioactive waste that affects the ecology of the oceans also poses a great danger to the life of the vast expanses of the Earth. Since 1946, the active merging of radioactive waste in liquid form into sea waters and the burial of similar and other wastes at the bottom of the seas by countries such as the United Kingdom, USA, France, Italy, the USSR, Germany, etc.
Pesticides pose a great threat to the ocean ecosystem. They are artificially created substances used to combat plant diseases and pests. The production of pesticides produces by-products that merge into and pollute the wastewater and which then enter the ocean.
Synthetic surfactants (surfactants) also contribute significantly to the pollution of the oceans. Detergents that are part of pesticides and synthetic-based detergents, which are widely used by the population, reduce the surface tension of water. They contain toxic ingredients that cause irreparable harm to organisms living in the water.
Carcinogenic substances tend to exhibit transforming activity and are capable of causing a violation of the embryonic development and mutation of living things. Their main source is the decomposition of organic elements during the burning of various materials, fuels, and wood. Carcinogens affect water pollution. Their concentration in the world water area exceeds 100 μg / kg dry matter mass.
Heavy metals used in production and falling into ocean waters pose a toxic hazard to marine biocenoses, especially cadmium, mercury and lead. About 455 thousand tons of mercury and 15-30 tons of lead are thrown into the hydrosphere annually.
Many countries that have access to the sea dump waste into the water for disposal. In particular, dumping of materials such as solid waste, drill slag, chemicals and explosives, industrial by-products, construction waste, etc. The volume of burials reaches 10% of the mass of all ocean pollution factors.
Of course, water bodies tend to self-clean, but to a certain limit. Such a strong pollution of the world's oceans, they can not recycle. Therefore, humanity should think about saving water resources, which are the most important source of physiological needs of the Earth’s population.