Sources of water pollution: point and nonpoint sources of pollution

Water is essential for all living organisms. Water comes to us in various ways; in between, it keeps getting polluted in many ways. The primary sources of water pollution are industrial, domestic discharge, and agriculture. The sources of water pollution categorized as point pollution sources and non-point pollution sources.

 Point sources of water pollution

 Point sources are easily predictable; we can easily identify them as it is particularly visible in one place. The point sources are the industries, domestic waste, underground coal mines, and sewage.

 Non-point sources of water pollution

 If sources of water pollution unpredictable or cannot be easily identified, it’s said to be non-point sources of pollution. It is difficult to find such sources in one place and it could be runoff from agriculture, atmospheric deposition, and accidental spills.

Different sources of water pollution

 Industrial discharge

 The majority of the industries are built near the bank of the river because they often require high water supply for the production process. During the industrial process, the water gets the organic matter, toxic, solid substrates as waste, and later the wastewater is discharged back into the river.

 The types of industries such as food processing, textile manufacturer, pulp and paper mills, electronic equipment manufacturer, chemical manufacturers, pharmaceutical manufacturers are mostly located at riverbank as they required highly water supplied.

 Industrial wastewater is often discharged into the river, and the river water used for drinking in many residential areas. Water containing chemical elements such as mercury, lead, chromium, and cadmium. So drinking this water can cause some diseases.

Domestic discharge

 Domestic waste includes wastewater, organic substance, etc go to sewage or a municipal waste management system. Municipalities dump this waste near the river bank and this garbage causes water and soil pollution. Sewage is another method of managing domestic and industrial waste and its improper management causes water pollution.


In many area sewer facilities is served. The household and industrial waste carried by sewer pipes to a sewage treatment plant. The sewage treatment plant processes the wastewater, and then this treated waste is released to the nearest water bodies. However, conventional treatment plants do not completely remove solids and organic materials, especially phosphorus. Phosphorus causes eutrophication that causes undesirable growth of some organisms. If ammonia remains in the discharged wastewater, it is hazardous to aquatic life because it reduces the amount of dissolved oxygen in the water bodies.

Also, conventional treatment plants cannot be processed some substances such as toxic compounds, petroleum products, and household cleaner that causing toxicity in the receiving water bodies. In conclusion, there is a need for some advanced sewage treatment plants to remove such toxic and harmful substances.


When we talk about agriculture as a source of water pollution, then pesticides are first in consideration. Farmer uses the pesticides for high yield. Pesticides enter the surface water due to soil erosion, especially water erosion. This water further goes to the river and ponds and spreads the pollution of water. In addition, animal waste is also a source of water pollution; Where this waste is discharged to the nearest lake, river or sewage.

Sediments are insoluble particles of soil and other solids that get suspended in water, and it’s moved away by soil erosion. High levels of suspended clay particles in water interfere with the penetration of sunlight. It reduces the photosynthetic activity of aquatic plants. Sediments may contain toxic pesticides and fertilizers that also threat to fishes.

Agriculture runoff degrades quality water. because it carries pesticides, fertilizer, organic waste, and animal waste with it.

Accidental spills

This is unpredictable occurrences in the ocean which causes water pollution, especially marine pollution. Leakage of the tanker in the ocean spills so many tons of oil in the ocean, which float on the surface of the ocean. In consequence, the amount of dissolved oxygen is decreased in the leakage area of the ocean. As a result, marine life is endangered.

Other sources of water pollution

Water runoff contains many pollutants such as automobile fluids, toxic substances, pesticides, agriculture waste, and animal waste. water runoff carrying these pollutants enters gutters, pipes, and later into rivers, streams, and lakes.

Atmospheric deposition is another source of water pollution where acidic compounds fall with rain on the land and water bodies. It increases the acidity of water sources and in such water, it becomes difficult for aquatic vegetation and aquatic organisms to live. Also, it’s dangerous for a wild animal to drink water.

Power plants are also sources of water pollution; they release hot water back to water sources which raise the temperature of water bodies. Also, radioactive substances are dangerous which shows hazardous effects such as cancer and genetic damage.

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