How to write an essay about water pollution
If you are going to write an essay or a paragraph on water pollution, it is crucial to understand the basics of the matter. The water is considered to be one of the most polluted sources of the world water supply. The rivers are stained by the accumulated dust and sand from the fields, smears, etc. The water of the lake that receives these effluents represents a fertile environment. There is a rapid growth of aquatic plants which capture the space in which fish usually live.
Dying off, seaweeds and other plants fall to the bottom and decompose due to the influence of oxygen-consuming aerobic bacteria, which worsens the habitat of fish. The lake is filled with seaweeds and small animals eating them. Blue-green algae (or cyanobacteria) make the water taste bad.
It should be emphasized in an “Air and water pollution” essay that the most serious problems of thermal pollution are associated with thermal power plants. Generating electricity with the use of steam is inefficient because in this case, 37-39% of coal energy and 31% of nuclear energy are used. Despite all the shortcomings, thermal power plants continue to exist.
Most of the energy of the fuel, which cannot be turned into electricity, is lost in the form of heat. The simplest way to get rid of this heat is to release it into the atmosphere. But the more economical method is to use water as a cooler because it is able to accumulate a huge amount of heat with a slight increase in own temperature. Later, water gradually releases heat into the air.
The usual way of using water to absorb heat (direct pumping of fresh lake or river water through a cooler and its returning to natural reservoirs without pre-cooling) causes serious environmental problems. A lake with an area of 810 hectares and a depth of about 8.7 m is required for a 1000 MW power plant.
In comparison with the surrounding water, power plants can raise the temperature by 5-15 °C. If the temperature of the water in the reservoir is 16 °C, the temperature of the water used at the station will be from 22 to 28 °C. In the summer, it can reach 30-36 °C.
Stress in a persuasive essay about water pollution that the rise in temperature in reservoirs adversely affects the life of aquatic organisms. During a long evolution, the cold-blooded underwater inhabitants have adapted to a certain temperature range. For each species, there is a temperature optimum which can vary slightly at some stages of the life cycle.
Within certain limits, underwater organisms are able to adapt to life at higher or lower temperatures. Most of them better adapt to life in warmer than in colder water. However, if a new temperature regime is established suddenly by the hot runoff from industrial enterprises, there is not enough time for acclimatization. As a result, living organisms experience a thermal shock and die.
Thermal shock is the ultimate result of thermal contamination. Release of heated drains into the reservoirs may have other, more insidious consequences. One of them is the influence on metabolic processes. According to Van’t Hoff’s law, the speed of chemical reaction doubles with increasing temperature for every 10 C.
Since the body temperature of cold-blooded organisms is regulated by the temperature of the surrounding environment, a rise in water temperature enhances the metabolism of fish and aquatic invertebrates, which increases their need for oxygen. At the same time, as the daily norm of the temperature of the surrounding environment decreases. the oxygen content in it decreases.
All these changes cause severe physiological stress and even death. In summer, increasing the water temperature by only a few degrees can cause a 100% mortality of fish and invertebrates, especially those that live near the southern boundaries of the temperature interval.
Artificial warming of water can significantly change the behavior of fish (cause untimely spawning, disrupt migration). If the destructive influence of power plants exceeds the ability of species to self-reproduction, the population declines.
The rise in water temperature can disrupt the structure of the plant world of reservoirs. Specific to cold water algae are replaced by more thermophilic species, and finally, at high temperatures, they are completely displaced.
If thermal pollution is aggravated by the entry of organic and mineral substances into the reservoir (fertilizers from fields, manure from farms, domestic sewage), the eutrophication process is observed.
It’s worth writing in a water pollution essay conclusion that the consequences of thermal influence cause huge damage to natural ecosystems and lead to a harmful change in the human environment. Negative impacts can be divided into the following groups: