“The introduction (directly or indirectly) of substances or energy into the marine environment (including estuaries) results in deleterious effects to living resources, hazards to human health,hindrance to marine activities.
– United Nations, 1971
Types of Water Pollution:
i. Surface water pollution: Surface water includes natural water found on the earth’s surface, like rivers,lakes, lagoons and oceans. Hazardous substances coming into contact with this surface water, dissolving or mixing
physically with the water can be called
surface water pollution.
ii. Groundwater pollution: Groundwater
contamination occurs when man-made products such as gasoline, oil and chemicals get into the ground water. In addition, untreated waste from septic tanks, toxic chemicals from underground storage tanks and leaky landfills contaminate groundwater.
iii. Microbiological pollution: In many
communities around the world, people drink untreated water (straight from a pond,river or stream). Sometimes there is natural pollution caused by micro-organism like viruses and bacteria. This natural pollution causes both aquatic and human illness.
iv. Oxygen depletion pollution:When oxygen levels in the water are depleted, relatively harmless aerobic micro-organisms die and anaerobic micro-organisms begin to thrive.
Some anaerobic micro-organisms are
harmful to people, animals and the
environment as they produce harmful toxins such as ammonia and sulfides.
Causes of Water Pollution:
Water pollution is caused due to several reasons. Here are the few major causes of water pollution:
1. Discharge of sewage and waste water: Sewage, garbage and liquid waste of households, agricultural runoff and effluents from factories are discharged into lakes and rivers. These wastes contain harmful chemicals and toxins which make the water poisonous for aquatic animals and plants.
2. Dumping of solid wastes: The dumping of solid wastes and litters in water bodies cause huge problems. 3. Discharge of industrial sastes:Industrial waste contains pollutant like asbestos, lead, mercury, grease oil and petrochemicals, which are extremely harmful to both people and
4. Oil Spill: Sea water gets polluted due to oil spilled from ships and tankers while travelling. The spilled oil does not dissolve in water and forms a thick sludge polluting the water.
5. Acid rain: Acid rain is pollution of water caused by air pollution. When the acidic particles caused by air pollution in the atmosphere mix with water vapor, it results in acid rain.
6. Global warming: Due to global warming, there is an increase in water temperature as a result aquatic plantsand animals are affected.
7. Eutrophication: Eutrophication is an
increased level of nutrients in water bodies. This results in bloom of algae in water. It also depletes the oxygen in water which negatively affects fish and other aquatic animal population.
Effects of Water Pollution:
Water pollution adversely affects the
health and life of man, animals and plants
alike. Polluted water is also harmful for
agriculture as it adversely affects the crops
and the soil fertility. Pollution of sea water
damages the oceanic life. The effects can be catastrophic, depending on the kind of chemicals, concentrations of the pollutants. The effects of water pollution are varied and depend on what chemicals are dumped and in which locations. Many water bodies near urban areas are highly polluted. This is the result of both garbage dumped by individuals and dangerous chemicals legally or illegally dumped by manufacturing industries, health centers and markets.
i. Death of aquatic animals: The main problem caused by water pollution is that it kills organisms that depend on these water bodies. Dead fish, crabs,birds and sea gulls, dolphins, and many other animals often wind up on beaches, killed by pollutants in their
ii. Disruption of food-chains: Pollution
disrupts the natural food chain as well. Pollutants such as lead and cadmium are eaten by tiny animals. Later, these animals are consumed by fish and the food chain continues disrupted at all higher levels.
iii. Diseases: The discharge of untreated and under-treated effluent contributes to severe ecological degradation.The indiscriminate human activities such as open defecation, solid waste dumping, discharge of drainage water are responsible for the pathogenic
bacteria water-borne diseases like Hepatitis-A, Typhoid, Malaria,Dysentery, Jaundice, Dengue fever,Viral fever and Worm infections.
iv. Destruction of Ecosystems:Ecosystems can be severely destroyed by water pollution. Many areas are now being affected by careless human pollution, and this pollution is coming back to hurt humans in many ways.
Remedial measures to control Water
1. Comprehensive water management plan.
2. Construction of proper storm drains and settling ponds.
3. Maintenance of drain line.
4. Effluent and sewage treatment plant.
5. Regular monitoring of water and waste
6. Stringent actions towards illegal dumping of waste into the water bodies.