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| Water Pollution |
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| For many years, chemicals were dumped into bodies of water without concern. While many countries have now banned such behavior, it continues to go on today. As the world has industrialized and its population has grown, the problem of water pollution has intensified. The simple fact that millions of people live along coastlines and near rivers means that these bodies of water are likely candidates for heavy and destructive pollution. MSES recognizes these problems and has the necessary expertise to assist you in dealing with water pollutions issues. |
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| EPA divides water pollution sources into two categories: point and non-point. Point sources of water pollution are stationary locations such as sewage treatment plants, factories and ships. Non-point sources are more diffused and include agricultural runoff, mining activities and paved roads. Under the Clean Water Act, the National Pollutant Discharge Elimination System (NPDES) permit program controls water pollution by regulating point sources that discharge pollutants into waters of the United States. EPA works with state and local authorities to monitor pollution levels in the nations water and provide status and trend information on a representative variety of ecosystems. The used water of a community is called wastewater, or sewage. If it is not treated before being discharged into waterways, serious pollution is the result. Historically, it has taken humanity quite a bit of time to come to grips with this problem. Water pollution also occurs when rainwater runoff from urban and industrial areas and from agricultural land and mining operations makes its way back to receiving waters (river, lake or ocean) and into the ground. Different types of water pollution include: |
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| Microbiological |
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| Disease-causing (pathogenic) microorganisms, like bacteria, viruses and protozoa can cause swimmers to get sick. Fish and shellfish can become contaminated and people who eat them can become ill. Some serious diseases like polio and cholera are waterborne. |
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| Chemical |
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| A whole variety of chemicals from industry, such as metals and solvents, and even chemicals which are formed from the breakdown of natural wastes (ammonia, for instance) are poisonous to fish and other aquatic life. Pesticides used in agriculture and around the home-- insecticides for controlling insects and herbicides for controlling weeds-- are another type of toxic chemical. Some of 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. |
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| Oxygen-depleting Substances |
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| Many wastes are biodegradable, that is, they can be broken down and used as food by microorganisms like bacteria. We tend to think of biodegradable wastes as being preferable to non-biodegradable ones, because they will be broken down and not remain in the environment for very long times. Too much biodegradable material, though, can cause the serious problem of oxygen depletion in receiving waters. |
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| Like fish, aerobic bacteria that live in water use oxygen gas which is dissolved in the water when they consume their "food". (The oxygen in the compound H2O, water, is chemically bound, and is not available for respiration (breathing)). 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. So 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. |
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| Once the oxygen is gone (depleted), other bacteria that do not need dissolved oxygen take over. But while aerobic microorganisms-- those 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 flammable methane (swamp gas). Add in the dead fish, and you see why we don't want large amounts of biodegradable materials entering lakes and streams. |
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| Nutrients |
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| The elements phosphorus and nitrogen are necessary for plant growth, and are plentiful in untreated wastewater. Added to lakes and streams, 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. Algae and weeds die and become bridgeable material, which can cause the problems mentioned above (and below). If the water is used as a drinking water source, algae can clog filters and impart unpleasant tastes and odors to the finished water. |
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| Suspended matter |
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| Some pollutants are dissolved in wastewater, meaning that the individual molecules or ions (electrically charged atoms or molecules) of the substance are mixed directly in between the molecules of water. Other pollutants, referred to as particulate matter, consist of much larger-- but still very small-- particles that are just suspended in the water. Although they may be kept in suspension by turbulence, once in the receiving 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 become anaerobic and contribute to problems mentioned above. Toxic materials can also accumulate in the sediment and affect the organisms that live there and can build up in fish that feed on them, and so be passed up the food chain, causing problems all 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 an aesthetic nuisance. |
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