Water is essential for life. It covers seventy percent of the earth's surface and makes up sixty-five percent of our bodies. Everyone wants clean water to drink, for recreation, and just to enjoy the sheer beauty of it. When water becomes polluted, it loses its value to us economically, and can become a threat to our health and to the survival of the animals living in it and the wildlife that depends on it. Although water pollution can occur through natural processes, it is mostly a result of human activities. The water we use is taken from lakes and rivers, and from underground. After we have used it and contaminated it most of it returns back to these locations. If the water is not treated before being discharged into waterways, serious pollution is the result. It has taken humanity years to realize what it is doing to its waters. To provide a better future for the next generation, now is the time to act on fixing the problem and to work together on preventing it from happening again.

One main source of water pollution is chemicals. A whole variety of chemicals from industry, such as metals and solvents, and even chemicals which are formed from the breakdown of natural wastes such as ammonia are poisonous to fish and other types of life in the oceans and seas. Pesticides used in agriculture and around the home can result in contaminate the water. Insecticides for controlling insects and herbicides for controlling weeds are another type of toxic chemicals that cause pollution. These can accumulate in fish and shellfish and poison people, animals, and birds that eat them. Materials like detergents and oils float and spoil the appearance of a water body, as well as being toxic; and many chemical pollutants have unpleasant odors. The Niagara River, between the US and Canada, even caught fire at one time because of flammable chemical wastes discharged into the water. This is just one of many cases of water pollution around the world.

Nutrients are yet another cause of water pollution. The two elements phosphorus and nitrogen are necessary for plant growth, and are plentiful in untreated wastewater. When added to lakes and streams or any other body of water, they cause nuisance growth of aquatic weeds, as well as "blooms" of algae, which are microscopic plants. This can cause several problems. Weeds can make a lake unsuitable for swimming and boating. They can even interfere with the fish and the other animals living in the water. Algae and weeds die and become biodegrable material, which can cause lots of different problems. Just to list a few, if the water is used as a drinking water source, algae can clog water filters and impart unpleasant tastes and odors to the finished water. This can cause expensive to fix problems as well as some health problems. All this can be fixed by treating wastewater. With just a little amount of effort we can solve this and many other water pollution problems around the world. 

One major cause of water pollution is suspended matter. Some pollutants are dissolved in wastewater. Others referred to as particulate matter, consist of much larger but still very small particles, which are just suspended in the water. They will eventually settle out and form silt or mud at the bottom. These sediments can decrease the depth of the body of water. If there is a lot of biodegradable organic material in the sediment, it will contribute to water pollution. Toxic materials can also accumulate in the sediment and affect the organisms, which live there and can build up in fish that feed on them, and so be passed up the food chain, causing problems along the way. Also, some of the particulate matter may be grease or be coated with grease, which is lighter than water, and float to the top, creating a nuisance. Just like major oil spills that happened in the oceans and seas over the globe. This causes the deaths of many living creatures that live in our waters. Even birds fall victims to this horrifying act.

Water pollution as we’ve seen can be caused by many things. Yet certain organisms found in the water can cause another form of water pollution. Disease-causing (pathogenic) microorganisms, like bacteria, viruses and protozoa live in bodies of water. They all can cause serious health problems. They contaminate large and small areas of water. If swimmers are in contaminated waters they can get sick. Also other life like Fish and shellfish can become contaminated and people who eat them can become ill. Serious diseases like polio and cholera are waterborne. These microorganisms cause most of the world’s diseases. This is just another reason to start cleaning up our waters.

Many wastes are biodegradable. Too much biodegradable material, though, can cause the serious problem of oxygen depletion in receiving waters. This is a cause of water pollution. Like fish, aerobic bacteria that live in water use oxygen gas which is dissolved in the water when they consume their food. But, oxygen is not very soluble in water. Even when the water is saturated with dissolved oxygen, it contains only about 1/25 the concentration that is present in air. If there is too much food in the water, the bacteria that are consuming it can easily use up all of the dissolved oxygen, leaving none for the fish, which will die of suffocation. Once the oxygen is gone, other bacteria take over. But while aerobic microorganisms which use dissolved oxygen convert the nitrogen, sulfur, and carbon compounds that are present in the wastewater into odorless and relatively harmless oxygenated forms like nitrates, sulfates and carbonates, these anaerobic microorganisms produce toxic and smelly ammonia, amines, and sulfides, and swamp gas. Add in the dead fish, and you see why we do not want large amounts of biodegradable materials entering lakes and streams.

Rainwater can actually cause water pollution. During heavy rain, street flooding occurs and usually leads directly to a waterway without any treatment. The runoff of pollutants from streets and yards into storm sewers contain oil and other automotive wastes, which may contain toxic metals and organic compounds as well as pesticides and nutrient-containing fertilizers from lawns and gardens, and pathogenic microorganisms from animal wastes. Further complicating the situation, the fact that while some cities and towns has completely separate sanitary and storm sewer systems, many others have combined systems. During rainy periods, combined sewers cause overloading of the treatment plant with extra water and contaminating waterways with untreated sewage from overflows. Even in cities with separate sewer systems, the flows to the treatment plants often increase greatly when it rains because of cracks or separations in the pipes, which allow groundwater or storm water from broken storm sewer pipes to infiltrate into the sanitary sewer or from direct inflow of storm water into manholes and from illegal connections of roof drains and sump pumps in buildings.

We know what causes water pollution so it is time to prevent it from happening. In order to keep our used water from spoiling our water resources, we have to stop pollutants or remove them before the water gets back into the environment.  In most developed countries, the wastewater from homes, businesses and factories is collected by sewers that carry it to one or more central treatment facilities. Most of these are located near bodies of water into which the treated wastewater is discharged. Industries, which are connected to sewers, should pre-treat their wastewaters before discharging them into the sewers, because they may contain materials, which will harm the sewers or the treatment plants or may be a danger to the people who work in maintaining the sewer system. Water pollution is just one on many forms of pollution that is happening around the world. We might not be able to totally stop pollution but we all can try to prevent it from starting. Water is essential to life and without it we can no longer exist. So remember that if one tosses a can in a lake what that can is doing for our future generation. It is our duty to take care of the world we live in because it is truly the only one we have.