Water pollution may be defined as a change in the physical-chemical and biological properties of water by the addition of undesirable substances which may have a harmful effect on human and aquatic life.
Sources of Water Pollution
Water pollution occurs due to its two sources-
Point Sources of Water Pollution
These sources discharge water pollutants directly into the water. For example, factories, underground coal mines, oil well situated near the water bodies at our point sources of water pollution.
Non-Point Sources of Water Pollution
These sources do not have any specific location for discharging pollutants in the water body. For example, runoff from field, lawns, construction, roads, and streets, etc.
Pollution of Freshwater
Freshwater is naturally occurring water on earth’s surface in ponds, rivers, lakes, and streams. Freshwater has a salt concentration of less than 1 percent and hence it is not saline. Pollution of freshwater is contamination by substances that make it unfit for natural use such as drinking, bathing, and washing purposes. Freshwater may be polluted in many ways, which are as follows:
Domestic Sewage discharge into reverse without treating it. Phosphate and nitrate ions from the excretory waste of humans and animals pollute the water. This may cause diseases like typhoid, cholera, dysentery, etc.
Organic wastes from agricultural fields with phosphate and nitrogen fertilizers that reach lakes, rivers, and sea.
Industrial waste from urban areas containing a high concentration of oil, heavy metals, and detergents, etc.
Pesticides, Insecticides such as DDT, and some industrial waste containing Mercury pollutes the water and reach the food chain and ultimately in humans, affecting aquatic and human health.
Effects of Water Pollution
- The presence of acids and alkalis in water destroy microorganisms thereby hindering the self-purification process and rivers.
- Water pollution adversely affects fish and other aquatic life.
- The toxic materials may enter the food chain.
- Polluted water cause epidemics, such as cholera, tuberculosis, jaundice, dysentery, typhoid, and diarrhea in human beings.
- The use of water contaminated with salts increases the alkalinity of the soil.
- Contamination of seawater due to oil slicks caused by the leakage of crude oil from oil tankers.
- Heavily polluted water affects the soil, decreases its fertility, and kill microorganisms.
Prevention and Control of Water Pollution
- Setting up sewage water treatment plants before the disposal into rivers.
- Use of septic tanks in the house to avoid direct outlet of fecal matter and other wastes.
- Biochemical wastes like a syringe, needle, soiled dressings, etc. to be disposed of properly.
- Total ban on nuclear waste dumping in the water.
- Avoid contamination of rivers, lakes, and ponds by washing clothes, bathing, etc.
- Not throwing waste food materials into open drains
- Treating industrial effluents before discharging into rivers, separate channels for rivers, and sewage water.
- Generating public awareness about the prevention of water pollution.