Causes of Water Pollution Rapid Urban Development Through the years, we have witnessed the exodus of people in the towns and cities. People began to build houses, roads, and big industries. Thereafter, there is a physical disturbance of the land and factories began to dump their chemical wastes in the bodies of water. Big factories flush down waste products in the water, and this is one of the major causes of ocean pollution. On the other hand, ordinary people also causes water pollution and not just big factories. Everyone is guilty of pouring chemicals or detergents in their drains or toilets. This toxic pollution can enter the wastewater from highway runoff. The highway runoff is usually covered with toxic chemicals such as spilled fuel, chemical additives, brake fluids, and exhaust emissions. When the rain pours, these chemicals are washed in the drains and into the rivers. With this, the school of fishes can get killed overnight. According to studies, the highway runoff in one year is equivalent to an oil tanker spill. Some highway runoffs come into the drains, and it can pollute the groundwater or accumulate in the land near the road. Thus, it becomes increasingly toxic year by year. Improper Sewage Disposal Nowadays, the disposal of sewage waste is becoming a major issue due to the growing population of the world. Its improper disposal can lead to several waterrelated diseases that can kill adults and children. Sewage disposal problem does not end easily. As soon as you flush the toilet, the waste has to go somewhere and even if it leaves the sewage treatment, there are still waste needed to dispose of. Thus, sewage waste is dumped into the oceans. In theory, sewage contains a natural substance which can be broken down by the environment easily. In fact, 90% of sewage contains water. However, in practice, sewage contains all other types of chemicals such as paper, plastic, and pharmaceutical products that they flush in the toilet. Also, when people are sick, they carry viruses with them. Thus, the sewage they produce carries those viruses and spread in the ocean. Nowadays, it is possible to catch typhoid, hepatitis, and cholera from the ocean and river. Use of Toxic Chemicals for the Plants Also, farmers have used harmful fertilizers to produce more and cope up with the demands of the growing population. This results in an algal bloom in the water. When the oxygen level of the water increases, it can also cause the extinction of underwater plants as well as the fishes. Dumping of Chemical Wastes by Big Factories Detergents are one of the chemicals dumped in the ocean. On the other hand, the Polychlorinated Biphenyls (PCBs) are highly toxic substances, and its traces are found to be discharged into the environment today. Other toxic pollution that is found in the water is caused by chemicals such as mercury, cadmium, and lead. Lead is used in gasoline or petrol, but it has been restricted in some counties. Meanwhile, cadmium and mercury are still used in batteries. Recently, a chemical named as Tributyltin (TBT) was also found in the affected bodies of water. In 1938, a Japanese factory discharged a huge amount of mercury metal in Minamata Bay. This heavy metal water pollution contaminated the fish stocks and it took almost ten years for the problem to come to the attention of the authorities. By that time, locals have already consumed the fishes, and about 2,000 residents were poisoned. More than 100 of people became disabled and got killed. Discharge of Radioactive Wastes High concentrations of radioactive waste can cause great alarm to the public. It can cause illness such as cancer which can ultimately cause the death of a person. In Europe, the biggest source of radioactive pollution is Sellafield and Cap La Hague. These companies discharge radioactive waste in the ocean which the currents carry around the world. Norway has been receiving significant doses of the radioactive pollution from Sellafield, and the government has repeatedly been complaining about the company. Both the Norwegian and the Irish government has been continuously pushing for the closure of the plant for years. Oil Spills According to studies, 12% of the oil that enters the ocean is due to tanker accidents while 70% of it comes from people pouring down oil on the land and routine shipping. However, tanker oil spills are destructive since it releases large amounts of oil at once. In the United States, one of the biggest oil spills is in 1989 when the tanker Exxon Valdez broke up in Prince William Sound in Alaska. During this incident, around 12 million gallons of oil were dumped in the ocean. With this, about 1000 to 2,000 sea otters and 250,000 seabirds were affected. Also, billions of salmons and herring eggs are destroyed due to the oil spill. Throwing of Plastics in the Ocean Plastics are one of the most common materials that can easily get washed away by the waves. Today, plastic is used in almost any kind of manufactured object from the clothes we wear, home items, and automobile parts. It is lightweight, and it floats easily. However, plastics are non-biodegradable, and it can affect the survival of the marine life for a very long time. Some people may say that plastics are not as poisonous as other chemicals, but they also present danger to the fishes, seabirds, and other marine animals. For example, plastic fishing line and other waste materials can choke and strangle a fish. Also, about half of the population of the world’s seabirds have eaten plastic and experts have found residues on their stomachs. Introduction of Alien Species in the Marine Environment Water pollution can be caused by alien or invasive species that are introduced into a new system which they do not belong. When they are outside of their normal environment, they don’t have natural predators. As such, they can run rapidly in the wild and crowd the usual plants or animals that live in the place. For example, the zebra mussels in the Great Lakes of the United States are carried by the wastewater flushed from the ships in Europe. Meanwhile, the Mediterranean Sea has been attacked by alien algae while the Black Sea it is an alien jellyfish. Other Forms of Pollution Some forms of pollution include thermal pollution coming from the power plants or factories which causes issues in the rivers. With the rising temperature in the water, it can reduce the amount of oxygen present in the water and decrease the level of aquatic life that the river can support. Also, the disruption of sediments or the fine-grained powders that moves from the rivers into the sea must also be considered. The water dams that are built as water reservoirs or to produce hydroelectric power can reduce the sediment flow. With this, the formation of beaches and flow of nutrients are reduced while the coastal erosion is increased. Meanwhile, increased sediments can be a problem too. During construction work, rock, soil, and fine powders can enter rivers in large quantities and make it turbid, silted, or muddy. The additional sediment can block the gills of several fishes and suffocate them. Thus, construction firms nowadays are spending their efforts to prevent this thing to happen.