Hydrosphere contamination

Many of the hydrosphere and pollutants they differ little from air pollutants. However, there are features associated with the fizikohimiceskimi processes and reactions.
On a global scale as the main pollutant of the hydrosphere today are oil and oil products in the aquatic environment as a result of oil extraction, transport, processing and utilization of fuels and industrial raw materials. Among the other products of industrial production a special place on its adverse effects on the aquatic environment are detergents is very toxic synthetic detergents. They are difficult to clean up, and yet in their ponds is not less than half the initial number. Detergents often form in layers of foam thickness on the locks and Rapids reaches 1 m or more. "Insidious" pollution by industrial waste water, are heavy metals: Mercury, lead, zinc, copper, chromium, Tin, etc., as well as radioactive. A particular danger to the aquatic environment is mercury (metilrtutnye faction).
One of the most significant sources of pollution of water resources is agriculture. This is evident especially in flushing fertilizer and hit them in the water. In science commonly known effect of eutrophication (or access to clean water, urban and rural (b) population in certain regions of the eftrofirovania) bodies of water due to pollution of nitrogen and phosphorus fertilizers. Nitrates and phosphates serve as some kind of fertilizer for aquatic plants. As a result of the "blossom" magnificently ponds, dramatically increasing food resources (phytoplankton, microseaweed surface layer), then increase the number of fish, shellfish and other organisms. Over time, however, the huge thickness of phytomass die off, consuming all the oxygen reserves. Hydrogen sulfide accumulates heavily in the pond, and he himself, agonizing, gradually "dies".
Increasingly, water contaminated herbicides and pesticides. The degree of accumulation and toxicity is largely dependent on hydro-dynamic and thermal characteristics of the water body. For example, in the neprotocnom reservoir base accumulates in bottom sediments, which become the source of chronic pollution. With a temperature increase of almost all the toxic effects of pesticides is increasing.
Sometimes the food chain fish fauna observed the peculiar effect of increased concentration of pesticides. So, if the marine plankton contains one unit of a known substance DDT, kedgeree is already 25 units, sea bird of prey — about 1500 units, and large marine animals — a lot more. Note also that representatives of Ichthyofauna, with more fat, represent a significant risk to humans. So, in the tissues of the fish caught in the Atlantic, Baltic and North seas and have a fat content of less than 6-7%, hloroorganiceskih almost no pesticide detected in fish tissue with fat content of 15-20% of these pesticides are always present.
Specific views of the hydrosphere is thermal. When power plants use water to condense the exhaust steam, they return it in water heated to 10-30° c. This leads to a reduction of the oxygen content in the water, increase the toxicity of the pollutant, reduce the access of light to the aquatic vegetation, encourage growth of harmful cyanobacteria, etc.
Dwell in some detail on the pollution of the water environment oil hydrocarbons. According to many sources, annually in oceans comes around 25-30 million tonnes of these substances. The way they hit different: 23% of total pollution of oil and oil products are the criminal dumping of ships ' ballast water and rinsing; 28% of the flow of the river waters; 17% of the combined loss of oil from tankers while loading; 16%-on-shore industrial waste water; 10% of the precipitation; 5% is the catastrophe of tankers and 1% for shelf drilling.
Once the oil starts to flow, in an attempt to get into a monomolecular layer. However, almost always formed patches (bullion) with clean oil in the Center, while on the periphery of patches appears neftevodnaa emulsion. Light oil fractions evaporate quickly. Thus, evaporation plays a huge role in the redistribution of hydrocarbons between the ocean and the atmosphere. Tanker crash could occur often cause serious pollution not only sea but also the atmosphere! Remaining after evaporation of high-boiling petroleum fractions form a resinous clumped, which can dive to the bottom. This effect is commonly used by dispersing agents, pogruzausih oil to the bottom. However, this is rejected, as dispersing agent (i.e. chemical) was more toxic than the oil itself.
In addition to the dissolution and evaporation of oil in the water, exposed to intensive biological and photochemical oxidation (for 1 l of oil oxidation requires oxygen so much as it is contained in 400 COMPANY l of water). It is easy to conclude that this leads to the impoverishment of the marine fauna in the coastal zone (mainly due to loss of oxygen).
The most easily soluble in an aqueous medium of oil are aromatic hydrocarbons, which, by the way, are considered to be the most toxic. They represent a mortal danger to fish, especially fish. Extremely toxic as diesel fuel, polluting water area of the port in the first place due to negligence (and often — and criminal actions) command ships.
Are particularly sensitive to oil pollution birds. Attempts to save them, usually fail, because although the plumage and hydrophobic, but deprived of protection from oil and oil products. Sometimes the bird enough oil in 2-3 cm2, so she died. If you try to wash birds beak, these products fall into her stomach and death is imminent. Kill the echinoderms, spiny lobsters, prawns and other shellfish.
The long-term environmental consequences of the pollution of the ocean and the entire hydrosphere petroleum and petroleum products, not explored yet. There are aspects that are still waiting for their research. So, we know that petroleum and petroleum products always contain polycyclic aromatic hydrocarbons (PAHs) are carcinogenic activity. Until now it was believed that the primary source of particularly dangerous substances is the spent engine oil that falls into the aquatic environment from ships. However, in recent years the science has formed the view that certain marine organisms can not only accumulate PAHs, but also synthesize them from crude oil. If this is confirmed, then the problems will only.