WATER POLLUTION.

 

Various contaminants pollute the water on earth. Water pollution like air pollution is of 2 types, natural and manmade.

In natural sources that pollute, Oil & Natural Gas can leak into the oceans and lakes from oil sources. These are called “Petroleum seeps”.  The world’s largest petroleum seep is the “Coal Oil Seep” off the coast of California.

Human activity contributes a lot to water pollution. Chemicals & oils are sometimes dumped by factories or may seep into waterways and this is known as run off. This creates a toxic environment for aquatic life. Runoff creates conditions for Cyanobacteria to breed and create what is known as the “Harmful Algal Bloom” (HAB). These blooms prevent aquatic life like plants and fish in the ocean, Rivers & Waterways.

Mining and drilling contributes to water pollution. AMD or “Acid Mine Drainage” is a major contributor to pollution of rivers and lakes near coal mines. Acid is used in coal mines to remove coal from the surrounding rocks. The acid leaks into the rivers or streams, where it reacts with rock and sand and releases sulphur creating a water body rich in sulphuric acid. This is toxic to all aquatic organisms, and makes the water non potable to humans and animals.

Oil spills are a major source of water pollution. In 2010 the “Deepwater Oil Rig” exploded in the gulf of Mexico, causing oil to gush from the ocean floor. In a few months hundreds of millions of gallons of oil mixed with the Mexican gulf waters. The spill created an oil slick on the surface with an area of 24000 Sq. Km. It affected the US states of Louisiana and Mississippi killing many plants and aquatic organisms.

Buried chemical wastes can also pollute water supplies. If not disposed of properly, the buried nuclear waste can cause a terrible hazard to organisms.

Sewage is big source of water pollution. If the sewage is untreated and is channelized either into a river or a sea, it causes huge damage and makes rivers polluted so that lesser number of fish can live  in them and also the water becomes non potable.

Another major source of water pollution is fertilizer used in agriculture. Fertlizer contains Nitrogen and Phosphorous and rainwater feeds this into rivers and lakes. These 2 chemicals cause Cyanobacteria to form HAB’s.

Rain washes other pollutants into lakes and rivers. It also washes pesticides off the plants into lakes and streams and they can also seep into groundwater.

Heat also pollutes water. Our thermal power plants use water as a coolant. After getting heated up the water is returned to the river. In some species the excess heat would not let the eggs of creatures to hatch and thereby restricts the growth of the species.

Another type of water pollution is garbage. Floating garbage makes the river difficult to fish in and also makes the aquatic life mistake things like plastic bags to be food and makes them consume it. Plastic bags and twine can kill many creatures both in the rivers and the seas as well as lakes. The fish that remain have high chemical toxic levels in them and if people eat them they would feel the effects.

Garbage also fouls the oceans. Many plastic bottles and other plastic trash are thrown into the sea from boats. The ocean currents carry plastics to certain places in the sea from where it cannot escape. The largest of these areas was already mentioned by me in my earlier write up on pollution. It is known as the “Great Pacific Garbage Patch”. Shockingly this garbage patch has an area of 1.60 million square kilometres which is stunning. That is exactly 10 times the area of Andhra Pradesh. It is a threat to fish and seabirds which mistake the plastic for food. You can have a look at the photograph of a part of the patch, and shockingly this is right in the middle of the Pacific ocean.