Many years of human activitychanged our planet beyond recognition, and the degree of these changes is increasingly progressing due to rapid technological development. Studies conducted over the past few years by experts from the US National Center for Environmental Analysis and Synthesis have shown that 40% of the world's ocean volume has been transformed by human exposure, and not for the better. Scientists analyzed 17 different activities that significantly affect the pollution of the world ocean - radioactive waste, greenhouse gases, shipping, etc., and also took into account chemical factors - oil, fertilizers, metals, etc.
The conclusions they draw are disappointing.As it turned out, the most polluted areas of the ocean are the seas: Norwegian, North, South China and East China. This is explained by the fact that many of their oil platforms are concentrated in their waters, fishing is actively conducted, and also heavily polluted rivers flow into it. The Mediterranean and the Japanese seas, as well as the coastal waters of the eastern part of the United States, are not much cleaner. Here, the coastlines are densely populated and there are many navigable paths.
There are, of course, land on the Earth that has not been affected by man, but there are only 3% of the entire water area of the world. They are located near the poles.
Let us consider in more detail the various sources most influencing the pollution of the world's oceans.
One of the main ones is oil falling intoworld waters with ballast water or draining waters of tankers or leaking out during its extraction and transportation. Every year the ocean replenishes 10 million tons of oil. Oil film covered already 20% of the world water area.
Radioactive waste from which it suffersthe ecology of the world's oceans, also poses a great danger to the life of the water expanses and depths of the Earth. Since 1946, the active discharge of radioactive waste in liquid form into sea waters and the burial of similar and other wastes on the seabed by such countries as Great Britain, USA, France, Italy, the USSR, Germany, etc. has begun.
Pesticides pose a major threat to theecosystems of the ocean. They are artificially created substances used to control plant diseases and pests. The production of pesticides gives by-products that merge into waste water and contaminate them and which then enter the ocean.
Synthetic surfactants (surface-activesubstances) also contribute to the pollution of the world's oceans. Detergents, which are part of pesticides and detergents on a synthetic basis, which are widely used by the population, lower the surface tension of water. They contain toxic ingredients, causing irreparable damage to organisms living in water.
Carcinogenic substances have the property of manifestingtransforming activity and are able to cause a violation of embryonic development and mutation of living beings. Their main source is the decomposition of organic elements in the combustion of various materials, fuel, wood. Carcinogenic substances affect the pollution of water bodies. Their concentration in the world water area exceeds 100 μg / kg of dry matter.
Heavy metals used in the production andfalling into oceanic waters, present a toxic hazard to marine biocenoses, especially cadmium, mercury and lead. Annually about 455 thousand tons of mercury and 15-30 tons of lead are thrown into the hydrosphere.
Many countries that have access to the sea,discharge in water waste for burial. In particular, dumping of materials such as solid waste, drill slag, chemical and explosives, industrial by-products, construction debris, etc. is being done. The volume of graves reaches 10% of the mass of all factors of ocean pollution.
Of course, water bodies have the property of self-cleaning, butup to a certain limit. Such a strong pollution of the world's ocean, they can not rework. Therefore, mankind should think about saving water resources, which are the most important source of physiological needs of the world population.
