According to P.K. Goel in his book Water Pollution – Causes, Effects Control, water is one of the most essential and valuable assets on earth (1). Approximately 70% of the earth’s surface is covered by water. Humans, animals and plants all need water to survive. Besides drinking water, water is used for cooking, washing clothes and utensils, flushing toilets, irrigation of the fields, etc. Unfortunately water is one of those natural resources that have been exploited by man to its most. Water pollution is a major problem and has a very bad impact on our ecosystem. My essay will elaborate upon sources and causes of water pollution, the effects of water pollution and how can water pollution be prevented and controlled.
What is water pollution? According to Jennifer Stefanow in her book Polluted Waters, water that has been rendered as unsuitable or harmful for any use due to the presence of contaminants is polluted water(6) . Water becomes impure due to its contact with something unclean(6). Many regions around the world lack clean water and this affects all living beings that include humans, animals, plants and organisms living in water.
What are the sources of water pollution? Pollutants can enter the water sources either directly or indirectly. According to Michael Hogan (2010) sources of surface water pollution, based on their origin can be grouped into two categories, point source pollutants and non- point source pollutants. Point source pollutants enter a water source directly. It can be carried through pipes and an example of point source pollutants includes discharge from a sewage treatment plant and industrial storm water from construction sites. According to the reports of National Water Quality Inventory (2000), nonpoint source pollution has a huge impact on the water quality of rivers and lakes. Non-point source (NPS) pollutants enter the water source indirectly. According to Michael Hogan (2010), one of the sources of non-point source pollution is urban runoff which is the contaminated storm water washed off of parking lots and roads. Another source is agricultural runoff and soil erosion runoff when rain falls over mud and landslides.
What are the causes of water pollution? Water pollution is caused when the pollutants are mixed with clean water. Human and natural causes are the two categories that cause water pollution. An article called Protecting Water Quality from Agriculture Runoff published in March 2005, explains agricultural activity as one of the human causes of water pollution. Agricultural runoff is nonpoint source pollution which happens when pesticides and other fertilizers sprayed on the crops, attached to the soil particles are washed off by the rainfall or excessive irrigation and leached into nearby lakes and rivers.
Jennifer Stefanow in her book Polluted Waters explains industrial activity as another human cause of water pollution. Manufacturing industries and factories that do not treat their toxic waste and chemicals and discharge it in oceans and rivers contribute to water pollution (12-29). An example of industrial waste from factories being dumped is in India into Ganges River. Jennifer Stefanow observes that Ganges River is also being polluted because of the hundreds of cremation that take place on the banks of the river, animals use the river as a toilet, also a lot of people who use it to cook and clean make it unclean (12-29). Another human cause of water pollution is the domestic activity. Jennifer Stefanow explains how pesticides and other fertilizers used in the household gardens and the chemicals used in car cleaning that loosen the pollutants from the car surfaces, are washed off by rain into drains that are not connected to water treatment plants (12-29). Thus the water flows directly into rivers or seas and pollutes the fresh water. The usage of laundry detergents, vehicle oil spills and litter not disposed in an appropriate way also get washed into drains.
Another human cause of water pollution is the non-appropriate manner of disposal of feces of animals infected by organisms in their body, which comes in contact with the water used for drinking through washing off by rain. Another human cause of water pollution is the large quantities of untreated waste from the mining activity that washes off through the rains and flows in the oceans and seas nearby. Another human cause of water pollution is the dumping of non-biodegradable products such as plastic containers, plastic bags, glass bottles, fishing net, etc into the water bodies. These products float on the surface and get washed up on the shores and riverbanks. According to Jennifer Stefanow (2004) another human cause of water pollution is the leakage of oil or petroleum from the oil refineries, tankers, ships and industrial waste. Oil also seeps naturally into the oceans from beneath the seabed. It is estimated that 180 million gallons of oil is leaked each year into seas and oceans and 45 percent soaks into seabed(12-29).
One of the natural causes of water pollution is volcanic eruptions. According to Jennifer Stefanow (2004) explosive eruptions eject huge quantities of broken rock, fine ash, lava and dust particles(12-29). These toxic chemicals get washed down to the ground in rain and enter the oceans and rivers. Wind also transports the ash and the fine particles to the water supplies nearby, polluting the water. Volcanic eruptions emit large amounts of gases that includes sulphur dioxide which returns to ground in form of acid rain resulting in water pollution(12-29). Harmful effects of acid rain will be discussed later in the effects of water pollution. Also the decomposition of the organic matter pollutes the water by releasing nutrients into it.
Sometimes heavy metals, found naturally in the ground, also get washed into oceans and rivers due to the heavy rain falls. Arsenic metal, found in large quantities in Bangladesh was washed by a lot of floods the country faces and was leached into thousands of well. This led to an increase in diseases such as cancer and other illnesses. Jennifer Stefanow (2004) observes that heavy metals like lead and mercury are toxic substances and if not disposed properly can dissolve in water in the form of industrial waste (12-29). Metals dissolved in water cause metal poisoning when the water or the seafood that has been affected by metals is consumed. Microorganisms such as bacteria, viruses, protozoan and invertebrates like worms are biological pollutants. These organisms present in natural water used for drinking by poor countries without the water treatment, are making people ill.
What are the effects of water pollution on the earth? The effects of water pollution are varied and depend on what chemicals and materials are dumped and who is affected and to what extent. According to Gary White, executive director and co-founder of Water Partners International, water pollution is one of the causes of deaths and diseases worldwide, leading to deaths of 14,000 people a day. Nearly 500 million people lack access to safe drinking water. An example of an affected area because of water pollution is the Boston Harbor, which is a natural harbour but was one of the most polluted waterways. The harbour was a dumping site for quite a long time. In 1980s before its cleaning started, harbour fish were diseased and it was unsafe to swim in polluted water. Dumping of non-biodegradable products such as plastic bags and fishing nets entangle and harm wildlife living in the water bodies. Jennifer Stefanow (2004) explains how sea turtles eat plastic bags considering it jellyfish which chokes their digestive system and kills them (12-29). Oil spills in water bodies results in lack of oxygen and sunlight to reach the aquatic life, also kills them.
Jennifer Stefanow (2004) argues that chemical fertilizers that leach into the rivers and lakes poison fish and other wildlife and also destroy habitats of animals (21). According to Jennifer Stefanow, the fertilizers containing phosphates and calcium that leach into water bodies increase the growth of plants known as eutrophication. Eutrophication reduces the amount of sunlight needed by the deep sea aquatic plants and reduces the amount of oxygen. Due to the lack of sunlight absorption by the aquatic plants, they cannot make their food. Jennifer Stefanow observes that excessive nutrients enter into the lakes and river and this has also caused rapid growth of algae in lakes such as Lough Erne and Lough Neagh (12-29). Also when the algae dies and decomposes, it uses most of the oxygen. A pesticide such as DDT is a man made organic compound and it does not occur naturally. DDT is a harmful pesticide as it does not breaks easily and lasts for a long time in the environment. So the presence of a DDT fertilizer in rivers and oceans can be very harmful for the fish as well as for the people who eat fish because if fish is affected by DDT, then the people consuming fish will have DDT stored in the tissues of their body as it is soluble in fats and organic solvents. Exceeding amounts of nitrate in drinking water can cause blue baby syndrome in babies.
According to Jennifer Stefanow, acid rain is formed when gases such as sulphur dioxide and nitrogen oxide are released into the atmosphere and react with water vapour in the air to form sulphuric acid and nitric acid (12-29). Acid rain causes toxic elements like mercury to be leached from the soil and is carried to the lakes and oceans where aquatic life is affected. Thus those who eat fish affected by mercury can have harmful effects on their health. Also the areas dependent on the usage of water from lakes without water treatment for drinking or other purposes are directly affected by acid rain. Acid rain also affects the plants by damaging their roots, causing the growth of the plant to be slow and resulting in less nutrients being available from plants.
How can water pollution be prevented and controlled? The best way to control pollution is to reduce it in the first place. To prevent water pollution farmers can adopt management skills and agricultural implements can be put into effect to achieve the purpose of lowering water pollution. Farmers can reduce soil erosion through rain by keeping the soil in place and reduce its transport. To avoid losing excessive nutrients to the water bodies, farmers must apply fertilizers and irrigation effectively according to the requirement of their field and not excessively. Animals should be confined to a limited area and their feces must be disposed properly to avoid its contact with the water bodies which will carry bacteria and virus. Thus carrying with them the pesticides and herbicides sprayed on the crops. To avoid the contamination of pesticides, Integrated Pest Management (IPM) techniques should be applied which restricts pesticide use and necessary measures should be taken to lower the pesticide movement from the field. Toxic fertilizers such as DDT should not be used as they pose a threat to the lives of people as well as animals and other wildlife. Thus DDT is banned in some countries including Canada.
The domestic sewage and the industrial wastewater with high concentration of pollutants should be treated with a high efficiency sewage treatment plant to avoid water pollution. Well designed treatment plants that have additional features, should be used to process sewage because of their efficiency as they have a capacity to remove 90 percent or more of these pollutants (1-30). Sewage treatment plants that are malfunctioning should be replaced or repaired immediately. Action should be taken about the households that are not served by an efficient sewage treatment plant and should be immediately connected to dispose sewage off in an appropriate manner (1-30). According to Miller and Hackett, government should ban dumping of waste and sewage in the water bodies and the action should be taken for the one who disobeys the law (525). Mining waste should be disposed off in an appropriate manner so that it does not pollute the water bodies.
Clean water is essential to life and we all have to act our part in order to preserve our environment and keep the earth as well as ourselves safe, from the approaching dangers because of the hazards of man’ activities.