What are the causes of water pollution?
Water pollution causes by the release of insoluble solid particles, soluble salts, sewage (waste water), garbage, low-level radioactive substances, industrial wastages, algae, bacteria. These substances go into the surface of groundwater or into the rivers, lakes, streams, and oceans, and water gets polluted or it interferes natural functioning of the water molecules in our ecosystem. In addition to the above substances, water pollution also causes by microorganisms, and heat from thermal energy or nuclear power generation plants of our environment.
Types of water pollution
According to the sources, water pollution can be classified into the following types given in the picture,
Water bodies can be polluted by different types of substances like industrial wastes, organic sewage wastes, chemical fertilizers (plant nutrients), disease-producing microorganisms, toxic chemicals, sediments, heat, petroleum oil, etc. It can affect the beneficial use of water discuss in this learning chemistry topic.
Industrial water pollution
The wastes discharged by the industries are called industrial wastes which included the compounds of metals (Hg, Cd, Pb, etc), organic compounds (alcohol, aldehydes, ketones, etc). Industrial wastes and sewage mainly contain organic compounds. These are used as food by bacteria in the lakes and rivers which rapidly increasing the population of bacteria in water. These bacteria oxidize nitrogen and phosphorus present in organic compounds. Therefore, the oxidation process consumes large quantities of oxygen gas dissolved in river water. The loss of dissolved oxygen from the river water causes water pollution to the death of fish and other aquatic life present in lakes, streams, rivers, and oceans.
Sulfur dioxide pollution
The air contains sulfur dioxide (SO2) that undergoes photolytic and catalytic oxidation to form SO3 which reacts with rainy water or moisture to form sulfuric acid rain also the secondary facts of the water pollution.
Organic pollutants in water
These types of pollutants contain synthetic detergents, herbicides, toxic pesticides, oil, and decomposition products. The detergents are surfactants (surface active agents) or organic compounds having polar or hydrophilic groups or non-polar or lyophilic groups soluble in water that has properties to causes water pollution. The surfactants are not decomposed by the bio-micro-organism (bacteria) and large quantities of detergent foams are collected in lakes and rivers.
Inorganic pollutants in water
Builders are generally sodium salts of phosphoric acid, carbonic acid, sulfuric acid, nitric acid, etc. The builders form stable soluble complexes of hardness producing ions. These complexes act as plant nutrients that cause the rapid growth of algae. The rapid growth of plants appears as a green sludge on the surface water. These plants bring de-oxygenation of water and hence aquatic animals die.
Toxic waste examples
The sources of water pollution caused by pesticides (D.D.T, endrin, dieldrin, B.H.C, polychlorinated biphenyls) is toxic for fishes or aquatic life that lives in rivers, lakes, streams. Endrin, even in traces is reported to be toxic for catfish and other varieties of fish. D.D.T affects the central nervous system of fishes and toxaphene has causes bone degeneration of fish.
Groundwater is the main source of drinking water for many peoples. Many regions of the United States depend mainly on groundwater for their domestic supply. Due to several human activities, the groundwater gets polluted by dissolving toxic chemical elements, substances, bacteria, and viruses. Therefore, due to water pollution, safe drinking water is the most common problem in many cities in different counties like the United States, England, India, Germany, etc. People use water purifiers to survive the problems of water pollution.
Effects of fertilizer on water pollution
To increasing the production of crops, we use large quantities of nitrate and phosphate fertilizers and pesticides. The excess use of nitrate or phosphate fertilizer (nutrients) is washed away from the agricultural lands into the ponds, lakes, and rivers with rainwater, and water gets polluted.
Wastewater from the fertilizer industry
Similarly, the wastewater coming from the fertilizer industry contains nitrate and phosphate fertilizers into rivers, lakes, and the sea is harmful to aquatic life or human beings. The presence of fertilizers in the polluted water increases the growth of algae and other aquatic plants which decompose to produce disagreeable order. The pollution containing nitrate salts is not fit for drinking by human beings which cannot be purified for drinking purposes.
Thermal pollution in our environment affects mainly the aquatic life of water. Heat can decrease the capacity of dissolved oxygen in water solution in rivers, lakes, or seas which increases the metabolism of fish. Some fishes cannot be alive with very low levels of dissolved oxygen. The main source of heat comes from the cooling water of power plants into rivers. The polluted water is much warmer than naturally occurring water bodies.
Effects of climate change on water resources
The effect of global warming or climate change also reduces the dissolved oxygen in the ocean’s water. Due to ocean pollution, some coastal areas formed dead zones where the dissolved oxygen is very low levels, and most of the higher forms of aquatic or water life vanish. The Gulf of Mexico is the largest dead zones (22,730 square kilometers) in the world.
Oil pollution in water
A large quantity of crude petroleum oil is spilled accidentally or intentionally into the sea water from the tankers (ships) or during the drilling operation causes water pollution in the sea. For example, the accidental leakage of 118,000 tonnes of crude petroleum oil from the big oil tankers (Torrey Canyon) into the water of the English Channel polluted the water of the surrounding area in a few hour’s time.
Effects of oil spills on the environment
The oil is lighter than water, oil forms a layer on the surface of the water which is called oil sticks. The oil spills prevented dissolving oxygen in the water which affects the life of aquatic life (animals or plants). Oil pollution affects the growth of plankton (plankton is a layer of tiny animals and plants that live on the surface of the sea) which disrupts the entire cycle of marine life or causes water pollution.
Microorganisms in water
Disease producing microorganism comes from the residents of a municipality are transmitted through water suppliers produces disease in living beings (animals or humans) which causes water pollution in our environment. Dysentery, typhoid, cholera, etc are transmitted through polluted water.
Solution of water pollution
- Water pollution can be controlled or prevented by the minimum use of excess nitrate and phosphate fertilizers. Minimum use of synthetic detergents, or bio-degradable detergents. Bio-degradable detergents are substances that can be decomposed by bacteria.
- Water pollution can be controlled, before throwing the industrial wastes and sewage into the river and lakes, the inorganic or organic substances are first treated chemically to neutralize the harmful substances present in them.
- The radioactive waste products obtained from the nuclear power plant, hospitals, and scientific laboratories should be enclosed in containers made of concrete and then dumped into the sea water to control these types of pollution.