Water pollution: causes, effects and diagnosis
Water pollution 'Central Pollution Control Board, Ministry of Environment and Forests, 2011
Presently, in view of erratic rainfall situation, low rainfall etc., industries should control their water consumption and treat the contaminated water generated properly and develop a process for its complete recycling. In order to avoid the situation of excessive exploitation of water resources, we have read in the last chapter that water gets polluted due to the presence of harmful substances in the water like micro-organisms, chemicals, contaminated water generated from industrial, domestic or commercial establishments etc. In fact, it is called water pollution. The physical, chemical and biological properties of water are affected by getting such harmful substances. Due to the harmful side effects of pollutants on water quality, polluted water is no longer eligible for domestic, commercial, industrial agriculture or any other common use.
In addition to drinking, household, irrigation, agricultural work, use of cattle, industrial and commercial activities etc. consumes a large amount of water and the water used is converted into contaminated water after use. As a residue in this contaminated water, during the activities carried out through them, the parts of substances or chemicals in contact with water remain. Their presence makes the water unsuitable for use. When this contaminated water is found in a clean water source, it also contaminates it. The contaminated water contains viruses, bacteria and other harmful micro-organisms along with organic and inorganic compounds and chemicals which pollute the waters according to their nature.
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| Water pollution: causes, effects and diagnosis |
ALSO READ - Causes and Prevention of air Pollution.
Pollution of water sources occurs in two ways: -
1. Pollution through point source
2. Pollution through Wide Source
1. Pollution through point source: -
When contaminated water comes out of a certain process and gets directly into the water source, it is called point source water pollution. In this, the nature and quantity of contaminated water found in the water source is known. Therefore, the pollution level can be reduced by treating this contaminated water. That is, point source water pollution can be reduced. Examples are the discharge of an industrial unit directly into a source of water through a contaminated water pipe, mixing of domestic contaminated water into a pond or river through a drain or drain.
2. Wide source water pollution: -
When the contaminated water generated during many human activities is found in a source through different means, it is called wide source water pollution. Due to coming from different mediums, it is not possible to collect and treat them together. Such as industrial and domestic contaminated water in rivers or coming through different means.
The pollutant points of different waters are also different.
1. Rivers: - Where the industrial contaminated water is found in the rivers through various drains, the domestic water is also immersed in it through drains etc. Also, fertilizers, pesticides and soil effluents along with the flow of water are also found in the rivers.
2. Pollution of seawater: - All the rivers eventually meet in the oceans. So they are definitely polluted through them. Industrial contaminated water and sewage, pesticides, fertilizers, heavy metals, plastics, etc. are found in the sea through rivers. Apart from these, maritime pollution also occurs due to maritime activities such as sea transport, exploitation of petroleum products from the sea, etc.
Only by observing the physical condition of the watershed can they be estimated to be polluted. The increase in the number of aquatic weeds along with the color of water, its smell, taste etc., decrease or death in the number of aquatic organisms such as fish and other animals, floating oily material on the surface, etc. are signs of water pollution. Sometimes water may be contaminated even if these symptoms are not present, such as acid or alkaline discharge or mixing in water bodies or meteorites of metallic pollutants. Chemical analysis of water is mandatory to detect such pollutants.
The nature of substances that pollute water is mainly of two types -
1. Biologically perishable
2. Biologically non-perishable
All organic matter pollutants are mainly biodegradable. These pollutants are destroyed by micro-organisms present in the water. In fact, organic materials are the food of microbes. These activities of micro organisms use large amounts of dissolved oxygen in water. This is the reason that when organic matter contaminants such as sewage or contaminated water of distillation industry are found in the water, then there is a significant decrease in the amount of dissolved oxygen in them, sometimes it happens that aquatic animals like fish etc. lack oxygen Are killed due to
Conversely, there are many pollutants that are not destroyed under normal conditions, such pollutants contain various metallic pollutants or inorganic salts.
Some of the major pollutants are: -
1. Sewage or other oxygen absorbent pollutants such as organic waste.
2. Pollutants of infectious nature such as waste from hospitals.
3. Fertilizers used for agricultural work, whose mixing in water increases the number of aquatic plants. Subsequently, these aquatic vegetation rotting in water gradually reduces or eliminates the use of dissolved oxygen in the water. In this way, due to rotting of vegetation, deodorant starts coming from the water.
4. Various chemicals, salts or metallic contaminated water, along with industrial contaminated water, are found in water bodies.
5. Chemical pesticides etc. used in agricultural work also mix with rainwater when coming to sources. These complex organic compounds are carcinogenic (carcinogenic) in nature.
6. Many radiation substances also flow with water and are found in natural waters.
7. The temperature of contaminated water coming out of many industries like distillation industry, power plant etc. is extremely high. Contaminated water with high temperature, combined with any water, increases its temperature. Which has a direct effect on aquatic organisms and flora.
8. Domestic solid wastes also cause major pollution of water.
Water pollutant factors can also be divided into three categories based on their physical condition: -
1. Depending on the suspended state in water: - Many water pollutants remain suspended in water. The size of these particles is more than one micro meter. They are suspended in the water and they sit down when the water is stagnant or stable for some time. They are easily filtered and separated.
2. Making colloidal state with water: - Some small size particles from suspended particles come into colloidal state with water. These pollutants cannot be separated from the normal filtering process, because their particles are so small that they pass through the filtration medium.
3. Dissolved Pollutants: - Many pollutants dissolve well in water. Such pollutants cannot be separated by normal filtration process. These can be separated by chemical methods only after the action of other reactants.
Apart from sewage, industrial contaminated water is also a major factor in polluting natural waters. Various scientists, environmentalists and chemists have divided them into different categories based on water pollutants. Ferguson has classified them into seven categories which include sewage, carcinogens, pollutants, organic chemicals, inorganic chemicals, solid wastes, radiation substances and high heat generating pollutants. Similarly, in 1972, they were classified on the basis of their physical and chemical properties and divided them into 10 categories. On this basis, they are characterized by their acidicity or alkalinity, the concentrations of minerals present in them, the amount of suspended particles, the tendency to use dissolved oxygen, the amount of dissolved organic matter, the amount of organic chemicals, the toxicity of pollutants, the presence of pathogenic germs, the chemical. Compounds such as the presence of chemicals containing nitrogen and phosphorus and very high temperatures .
In addition to the liquid wastes from industries, chemicals used in various activities or the water generated from them also contain harmful substances. These soluble or insoluble substances combined in water sources make it contaminated or unfit for drinking. We will briefly discuss some of these.
1. Pesticide or Biocidal: -
There are many pests in our ecosystem; Those who depend on flora or botanical products. In addition to insects, parasitic bacteria or viruses that grow on crops are also found in large numbers. When pests or other parasites attack the crops, the entire crop is licked on sight. In order to save crops, pesticides are sprayed on the crops as necessary.
Most chemicals used as pesticides are complex organic compounds. Most such compounds are carcinogenic to organic matter. These chemicals are sprayed on the surface of plants by spraying them. On rainy days, when the plants are watered, these chemicals dissolve in water, or form colloidal solutions with water. In both the states, they come out in the water source and they contaminate it and make it harmful.
Similarly, bio-destructors are used on food items while storing water etc. These bio-destructors also play an important role in polluting the water bodies.
Most pasticides or biocides are chlorinated hydrocarbons. These pasticides are non-biodegradable or biologically non-biodegradable chemicals. That is why their extreme effects fall on water bodies and aquatic life.
2. Sewage drainage: -
Residential colonies have also expanded with the country's growing population. The amount of sewage waste has also increased in the same proportion. Even today, there is no satisfactory system of sewage treatment in our country. As a result, a large amount of these contaminated water gets directly into the rivers. Domestic contaminated water contains a large amount of organic matter, which reduces the amount of dissolved oxygen in the rivers and creates life-threatening problems for aquatic organisms.
Apart from this, they are also factors of diseases. Many infectious diseases spread due to these.
3. Industrial contaminated water: -
Contaminated water of different nature is produced from different industries. These have different effects on natural waters. The amount of organic matter in the contaminated water from food-based industries is very high, thereby significantly reducing the concentration of dissolved oxygen in the water bodies. Similarly, the contaminated water generated from distilleries, paper mills etc. also exerts the same effect. The contaminated water coming out of chemical industries, stains and pharmaceutical manufacturing factories is very complex in nature and affects the water bodies in many ways. Many industrial discharges have high quantities of heavy metals. These metals adversely affect aquatic organisms and flora. It also has many side effects on human life. By using such contaminated water, they directly affect them, as well as by consuming heavy metal flora or fish affected by them, these metals reach the human body. These heavy metals have long-term effects in the human body.
4. Industrial and domestic solid waste and their abduction: -
Industrial or domestic solid waste directly from being immersed in water bodies and in addition to run off water from the disposal site made for them, or the leachate generated from them directly or mixed with rainwater in the water bodies also Water is polluted.
5. From agricultural wastes: -
Large amounts of water are used for irrigation in agricultural work. Except for the part of water used in agriculture that evaporates or is absorbed by the land, the rest flows back into the water streams. In this way, it sheds pesticides, organic matter, soil and its residues, including natural or chemical fertilizers added to the fields and mix them in the water bodies.
6. Radiated chemicals: -
Contaminated water from nuclear power centers, nuclear test centers, laboratories that carry out radiation experiments, etc., contain large amounts of radioisotopes. These leave the water and make it highly harmful.
7. From oil waste and petroleum products: -
During marine activities, seepage, exploitation of oil and petroleum products, etc., large quantities of oil and petroleum materials waste in seawater together affect the watersheds.
8. Thermal pollution: -
Water from thermal power plants is used in cooling in chemical industry and many other industries. Often, high temperature contaminated water is also produced during the process. These types of water, combined with normal water, increase its temperature several times than normal. As a result, aquatic life and ecosystems are adversely affected.
9. Pollution from plastic and polyethylene bags: -
Plastic is generally not biodegradable. Some of its products, such as polystyrene, are fissioned, but after fission, they turn into low but harmful products. Polyethylene bags are also not biologically destroyed. When they are put in water, they die due to trapping of aquatic animals in them. Similarly, aquatic vegetation also traps and rot in them and affects the quality of water.
Diagnosis for water pollution problem
The main sources of water pollution are industrial effluents and contaminated water discharged from domestic sources.
Large amounts of contaminated water are generated from various industrial activities. The nature and quantity of pollutants present in this contaminated water varies according to industrial production. The contaminated water originating from some industries is of a highly polluting nature, dirty or toxic. While the contaminated water of some industries is not much polluted. In addition, the water released from cooling, boiler blowdown, etc. is mostly normal. Which can either be taken to another task or recycled.
The most important way to avoid the situation of water pollution is to prevent polluted water from getting into clean water sources. For this, after proper treatment of the contaminated water coming out of each source, it will be appropriate to use it or recycle it in the process. After treatment as per the prescribed criteria, the treated water should be flown into the water source only if necessary.
Apart from this, polluting activities occurring in water bodies like defecation on rivers / ponds etc. activities; Excavation of household waste, idols or worship material, carcasses should be used to curb excuses in rivers etc.
Steps should also be considered to prevent silt from flowing into the rivers, chemical fertilizers used in the orchard fields and pesticides from overflowing by normal flow of rain.
Presently, in view of erratic rainfall situation, low rainfall etc., industries should control their water consumption and treat the contaminated water generated properly and develop a process for its complete recycling. So that the situation of excessive exploitation of water bodies can be avoided. For this, industries should adopt the latest treatment process / plants for treatment of contaminated water effectively and make zero discharge conditions as possible. In this way, domestic contaminated water can be treated and used for industrial use, plantation, roads, spraying water in industries etc.
The best way to protect the natural water resources especially rivers from the ill effects of water pollution is to stop the discharge of contaminated water in them.
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