Sea Pollution – An Overview

The seas are treated as giant dustbins by all mankind. Huge amounts of waste materials are dumped into them on a daily basis. Sea pollution is caused mainly by way of rivers, outflow pipes, and drains.

All the brunt of human wastes is borne by the seas. Whether it is by deliberate dumping or by natural run-off from the land, the fact remains that all anthropogenic activities add to sea pollution. As a matter of fact, almost eighty percent of all sea pollution comes from activities that are land-based. Many pollutants even get deposited in coastal waters and estuaries. The pollutants enter marine food chains and build up their concentration until they reach levels of toxicity.

The toxic water poisons all creatures of the sea including fish which is a staple food for mankind. When fish consume toxic water, they become poisonous themselves. This affects those humans who eat these poisonous fish.

Large quantities of waste materials and toxins are broken up, dispersed, or dissolved by the seas. However, most plastic wastes do not break down. They just wash around islands and coasts for years. Such is the case with pesticides as well. Deadly substances such as DDT and PCBs are hard to get rid of once they enter the sea water. Oil that is spilled into the water body each year by ships or is carried into the sea through city drains is also hard to remove.

More oil is disposed off into the sea via tankers either due to accidental spills or during cleaning. Oil leaks at wells are another major source of sea pollution. Even though some of the oil evaporates from the land into the air, but it eventually condenses and falls into the sea through atmospheric circulation in the weather system.

Sea pollution is also caused due to domestic wastes and human sewage water, poisonous metal and acid outflows from factories, engine oil from garages and roadside drains, and chemicals washed off from farms by rain and rubble from building sites.

Sewage is another dominant sea pollutant. Many sewage pipelines were built years ago, when the effects of pollution were not known. It was thought that the sea would dilute the sewage. However, even after the ill-effects were known, the amount of sewage being dumped into the seas kept on increasing considerably.

If this trend of pollution continues, the world will face a drastic change. It would definitely become a place full of pollution and unsuitable for all flora and fauna. The seas and oceans might even be so drenched with silt and pollutants that no water may be left fit for consumption. Therefore, sea pollution must be stopped or at least brought down to manageable levels, if mankind and animal life is to survive.