7.1.2.1. PARAMETERS OF WATER POLLUTION

Chemical examination of water (tests): pH; Biological Oxygen Demand (BOD), Dissolved Oxygen (DO), etc are some of the chemical tests to find the stage of pollution of water.

Chemical tests are used to analyze the quality of water and determine its level of pollution. Key parameters include:

1. pH: This indicates how acidic or alkaline the water is.
2. Biological Oxygen Demand (BOD): This measures the amount of oxygen that microorganisms use in breaking down organic matter at a specific temperature over a period of time.
3. Dissolved Oxygen (DO): This refers to the amount of oxygen available in water, which is crucial for aquatic life. If these parameters are out of balance, they suggest that the water is polluted and may pose risks to health and the environment.

Imagine a fish tank. If the pH is too high or too low, the fish may become stressed or die. Similarly, if there isn't enough dissolved oxygen, the fish will struggle to breathe, which illustrates the importance of these chemical tests in maintaining a healthy aquatic environment.

1. pH: The value of pH gives the degree of acidity or alkalinity of polluted water. Determination of pH is important in calculating the coagulant (thick or thin) dose.

The pH level of water plays a crucial role in determining its quality. It quantifies how acidic or basic the water is:

• Acidic water (pH less than 7) can be harmful to aquatic life and often indicates pollution.
• Alkaline water (pH above 7) can also indicate issues, such as the presence of harmful substances. Understanding the pH helps water treatment facilities decide what treatments, or coagulants, are needed to purify the water.

Consider baking. When making a cake, the right balance of acidic (like vinegar) and alkaline ingredients (like baking soda) is essential for it to rise properly. Similarly, water must maintain a specific pH range to be healthy for ecosystems.

2. Biological Oxygen Demand (BOD): It is defined as the quantity of oxygen utilized by microorganisms at a temperature of 20°C, generally measured for 5 days. When water is polluted by unwanted materials, naturally the O2 content gets reduced and that water becomes not fit for consumption either by human beings or animals or plants.

BOD is an essential measure of water pollution. It reflects the amount of oxygen that bacteria will consume while breaking down organic matter in water:

• Higher BOD levels indicate that there is a lot of organic material present, suggesting heavy pollution.
• Low BOD levels mean the water is cleaner and can support aquatic life. A water body with high BOD may not be suitable for drinking or recreational activities due to the potential harmful microorganisms present.

Think of a busy restaurant where the chefs use a lot of water to wash dishes and prepare food. If there are too many dirty dishes (high BOD), it indicates that the restaurant is overwhelmed and might not have clean water left for customers. Similarly, high BOD in water indicates too many contaminants.

COMMON TYPES OF WATER POLLUTANTS: A) Based on sources B) Based on natures A) Based on sources: a) Disease causing agents: Bacteria, viruses, protozoa that enter water from domestic sewage and animal wastes. b) Water soluble inorganic chemicals: Acids, salts and compounds of toxic metals such as Lead, Mercury can make water unfit to drink... c) Water Soluble Organic chemicals: Oil, gasoline (a type of oil is obtained from petroleum), pesticides, detergents and many other water soluble chemicals that threaten human health and harm fish. d) Heat: Large quantity of water is heated when it is used in the cooling towers of thermal power plants. When this hot water is discharged into the nearby water bodies, it causes an increase in its temperature. e) Sewage: sewage is wastewater from the municipal area where there is human habitation. Sewage which comes from homes is called domestic sewage.

Water pollutants can be classified by their source. Key categories include:

• Disease-causing agents: Microorganisms like bacteria and viruses can contaminate water from sewage.
• Inorganic chemicals: Metals like lead and mercury are harmful and make water unsafe to drink.
• Organic chemicals: Substances like oil and pesticides can poison aquatic life and disrupt ecosystems.
• Heat pollution: Industrial processes can heat water, which harms fish by decreasing oxygen levels.
• Sewage: Domestic wastewater carries pathogens and nutrients that can lead to health issues and eutrophication.

Imagine a bowl of soup with various ingredients. If you add spoiled food (like bacteria), toxic elements (like heavy metals), or too much salt (like chemicals), the soup becomes unsafe to eat. Just like that, pollutants affect the quality and safety of water.

B) Based on natures:

1. Domestic water pollution: Sewage is a part of domestic water pollution...
2. Agricultural Water Pollution: Water required for plants for its growth...
3. Industrial water pollution: Many industries discharge waste materials containing harmful chemicals. Such Industrial wastes are called effluents.

Water pollution can also be categorized by its impact on the ecosystem:

1. Domestic pollution: Household sewage can harbor pathogens and nutrient overloads that lead to illness and environmental degradation.
2. Agricultural pollution: Excess fertilizers and runoff can cause eutrophication, disrupting local ecosystems and harming aquatic life.
3. Industrial pollution: Factories releasing effluents can introduce toxic substances that negatively affect both human health and the environment.

Consider a community garden. If one neighbor uses too many chemicals (agricultural pollution), it can harm the plants and the entire garden's ecosystem. Similarly, if a factory dumps waste (industrial pollution) into a nearby river, it risks harming everyone who depends on that water.

CONTROL MEASURES OF WATER POLLUTION:

1. Drinking water should be boiled, cooled, and then used.
2. Disinfection of drinking water should be done by using chemicals like bleaching powder.
3. Pesticides and insecticides should be prevented from nearby use of water bodies.
4. Drainage water should not be allowed to mix with drinking water.
5. Drainage system should be maintained properly.
6. Chlorination process is to be adopted for drinking water.

Control measures are essential in combating water pollution:

1. Boiling water kills pathogens, making it safer for drinking.
2. Chemicals like bleaching powder disinfect water, eliminating harmful microorganisms.
3. Regulations are necessary to prevent the use of pesticides near water bodies to protect aquatic life.
4. Proper drainage systems help prevent contamination of drinking water sources.
5. Regular maintenance ensures that drainage systems function correctly, preventing leaks and pollution.
6. Chlorination is a standard method to ensure water is disinfected before consumption.

Think of how we wash our hands to keep germs at bay. Just like handwashing prevents illness, these control measures are like keeping our water clean and safe for all users. If you don’t take care of the water systems, it’s like leaving your hands dirty.

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