7.1.2.2. COMMON TYPES OF WATER POLLUTANTS

A) Based on sources:

a) Disease causing agents: Bacteria, viruses, protozoan 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, harm fishes and other aquatic life. Also Nitrate, Phosphate compounds dissolve in water that can cause excessive growth of algae, which then die and decay, depleting dissolved O in water and killing fish. 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 waste water from municipal area where there is human habitation. Sewage which comes from homes is called domestic sewage.

This section discusses various sources of water pollutants. Disease-causing agents like bacteria and viruses often enter water systems from sewage and animal waste, leading to various health problems. Inorganic chemicals, particularly heavy metals like lead and mercury, can dissolve in water and create hazardous conditions for aquatic life and humans. When organic chemicals such as oil and pesticides are present in water, they pose serious risks to health and the ecosystem. Hot water discharged from industries can also raise water temperatures, which disrupts aquatic ecosystems. Lastly, domestic sewage contributes significantly to water pollution.

Think of water sources like a neighborhood park where kids play and drink water. If trash (like plastic and food wrappers) is left in the park, it can make the place dirty and unsafe for children. Similarly, if sewage and chemicals pollute water bodies, it makes the water unsafe for everyone.

B) Based on natures:

1. Domestic water pollution: Sewage is a part of domestic water pollution. Domestic sewage not only contains unwanted waste materials, but it is also infested with harmful bacteria, virus etc. These are responsible for causing diseases in animals and human beings, if they drink this polluted water and even plants may die if polluted water is provided. Domestic water pollution leads to Diarrhea, Cholera and Typhoid in human beings.

2. Agricultural Water Pollution: Water require for plants for its growth. Major irrigation, minor irrigation, sprinkler irrigation, drip irrigation, lift irrigation carry waste substances and causing water pollution in addition to the utilization of fertilizer and pesticides. Agricultural water pollution leads to Eutrophication & Water Bloom.

This part categorizes water pollution into two main types based on nature. The first is domestic water pollution, which primarily comes from sewage containing harmful bacteria and viruses that can lead to serious diseases like diarrhea and cholera when contaminated water is consumed. The second type is agricultural water pollution. In this case, water used for irrigation purposes often carries fertilizers and pesticides that can contaminate water bodies, leading to problems like eutrophication, where excess nutrients promote excessive algae growth, harming aquatic ecosystems.

Imagine if someone were to wash their dirty clothes in a stream where everyone gets water for drinking. This 'domestic water pollution' could make people sick. Similarly, if farmers use lots of fertilizers on their crops and the rains wash the excess into rivers, it’s like adding too much sugar to a dish – it can ruin the whole meal! In water, this is called eutrophication, leading to too many algae that suffocate fish.

3. Industrial water pollution: Many industries discharge waste materials containing harmful chemicals. Such Industrial wastes are called effluents. The river Godavari is polluted because of effluents released by the paper industry. It affects the entire water ecosystem causing enormous damage to fishes, prawns and fresh water animals. Eg: Minamata disease & Fluorosis.

This section highlights industrial water pollution, where factories release toxic waste (effluents) into water bodies, severely disrupting local ecosystems. An example of this is the pollution of the Godavari River by paper industry discharges, which harm fish and other aquatic life. It mentions specific diseases linked to water pollution, such as Minamata disease caused by mercury poisoning, and fluorosis from excessive fluoride in water.

Imagine a factory near a river dumping dirty water filled with chemicals into it. It’s like spilling paint into a pool – it ruins the water and affects everything that depends on it. The fish in the river suffer just like kids would if they played in the painted pool. Similarly, when people eat fish contaminated with mercury from polluted waters, they can get very sick, just as the Minamata disease shows.

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