There are more than 326 million trillion gallons of water on Earth. Less than 3 % of all this water is fresh water and of that amount, more than two-thirds is locked up in ice caps and glaciers. With so much water around it seems like there is enough to see us through for millions of years. But did you know that even water, which seems to be in abundance, might one day become scarce? Each time you throw something as garbage, think of where it will finally end up. Whether it is a plastic glass, your broken cell phone or the used up battery cells from your portable CD/MP3 player, they all contribute in some way to environmental pollution and are also hazardous to life. Not only are they biodegradable, but also disposing of them has their own risks as they release harmful toxins into the air and surrounding soil and ground water. All these cause water pollution .!
What is water pollution?
Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater). Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds. Water pollution affects plants and organisms living in these bodies of water. In almost all cases the effect is damaging not only to individual species and populations, but also to the natural biological communities. Water pollution is a major global problem which requires ongoing evaluation and revision of water resource policy at all levels. It has been suggested that it is the leading word wide cause of deaths and diseases, and that it accounts for the deaths of more than 14,000 people daily. An estimated 700 million Indians have no access to a proper toilet, and 1,000 Indian children die of diarrheal sickness every day.
Some 90% of China’s cities suffer from some degree of water pollution, and nearly 500 million people lack access to safe drinking water. In addition to the acute problems of water pollution in developing countries, developed countries continue to struggle with pollution problems as well. In the most recent national report on water quality in the United States, 45 percent of assessed stream miles, 47 percent of assessed lake acres, and 32 percent of assessed bays and estuarinesquare miles were classified as polluted. Water is typically referred to as polluted when it is impaired by anthropogenic contaminants and either does not support a human use, such as drinking water, and/or undergoes a marked shift in its ability to support its constituent biotic communities, such as fish. Natural phenomena such as volcanoes, algae blooms, storms, and earthquakes also cause major changes in water quality and the ecological status of water.
Sources and effects of water pollution
Water pollution can be caused in a number of ways, one of the most polluting being city sewage and industrial waste discharge. Indirect sources of water pollution include contaminants that enter the water supply from soils or groundwater systems and from the atmosphere acid rain. Ground water pollution
Interactions between groundwater and surface water are complex. Consequently, groundwater pollution, sometimes referred to as groundwater contamination, is not as easily classified as surface water pollution. By its very nature, groundwater aquifers are susceptible to contamination from sources that may not directly affect surface water bodies, and the distinction of point vs. non-point source may be irrelevant. A spill or ongoing releases of chemical orradionuclide contaminants into soil (located away from a surface water body) may not create point source or non-point source pollution, but can contaminate the aquifer below, defined as a toxin plume. The movement of the plume, called a plume front, may be analyzed through a hydrological transport model or groundwater model. Analysis of groundwater contamination may focus on the soil characteristics and site geology, hydrogeology, hydrology, and the nature of the contaminants.
Types of water pollutants
There are several classes of water pollutants. The first are disease-causing agents. These are bacteria, viruses, protozoa and parasitic worms that enter sewage systems and untreated waste. A second category of water pollutants is oxygen-demanding wastes; wastes that can be decomposed by oxygen-requiring bacteria. When large populations of decomposing bacteria are converting these wastes it can deplete oxygen levels in the water. This causes other organisms in the water, such as fish, to die. A third class of water pollutants is water-soluble inorganic pollutants, such as acids, salts and toxic metals.
Large quantities of these compounds will make water unfit to drink and will cause the death of aquatic life. Another class of water pollutants are nutrients; they are water-soluble nitrates and phosphates that cause excessive growth of algae and other water plants, which deplete the water’s oxygen supply. This kills fish and, when found in drinking water, can kill young children. Water can also be polluted by a number of organic compounds such as oil, plastics and pesticides, which are harmful to humans and all plants and animals in the water. A very dangerous category is suspended sediment, because it causes depletion in the water’s light absorption and the particles spread dangerous compounds such as pesticides through the water. Finally, water-soluble radioactive compounds can cause cancer, birth defects and genetic damage and are thus very dangerous water pollutants.
Pollutants can be of varying kinds: organic, inorganic, radioactive and so on. Organic pollutants
Organic compounds are compounds that consist of long bonds, usually made up of carbon. Many organic compounds are basic fabrics of living organisms. Molecules built of carbon and of carbon and hydrogen are non-Polari and have little to no water solubility. They have little to no electrical charge. The behavior of organic compounds is dependent upon their molecular structure, size and shape and the presence of functional groups that are important determinants of toxicity. It is important to know the structure of organic compounds, in order to predict their fate in living organisms and the environment. The organic compounds that are dangerous to the environment are all man-made and have only existed during the last century. There are many different types of organic pollutants, examples are: – Hydrocarbons. These are carbon-hydrogen bonds.
– PCB’s are stable and un reactive fluids that are used as hydraulic fluids, coolant/ insulation fluids in transformers and plasticizers in paints. – Insecticides such as DDT’s are very dangerous because they accumulate in fat tissues of lower animals and then enter the food chain. – Detergents. These can be both polair and non-polair.
Some inorganic pollutants are not particularly toxic, but are still a danger to the environment because they are used so extensively. These include fertilizers, such as nitrates and phosphates. Nitrates and phosphates cause algal blooms in surface water, which causes the oxygen level of the water to decline. This causes oxygen starvation because of the uptake of oxygen by microrganisms that brake down algae. This is called eutrophication.
Metals are good conductors of electricity and generally enter chemical reactions as positive ions, known as cations. Metals are natural substances that have consisted through weathering of ore bodies, where they were deposited during volcanic action. They can be relocated into situations where they can cause serious environmental damage. Examples of metals are: lead, zinc, manganese, calcium and potassium. They can be found in surface waters in their stable ionic forms. Unnatural metals can be very dangerous, because they often come from man-made nuclear reactions and can be strongly radioactive. Metals can react to dangerous products with other ions. They are often involved in electron transfer reactions involving oxygen. This can lead to the formation of toxic oxyradicals.
The half-lives and the ways of decay of radioactive isotopes determine how dangerous they are to humans. Humans create all radioactive isotopes in the nuclear industry. When an atom of a radioactive substance decays, it can produce four kinds of particles: alpha, beta, gamma and neutrons. Alpha particles can only travel a short distance through air and human tissues, but they can be very damaging if they collide with cells because of their large mass. They are positively charged. Beta particles are more penetrating, but they do much less damage than alpha particles. They are negatively charged. Gamma rays are highly penetrating. Their damage is similar to that of beta rays. Neutrons are liberated through radiation and react with other elements through collision. They are the basis for nuclear fission in a reactor. The radioactivity of a substance is measured in bequerels, but this does not express the amount of tissue damage the radiation causes. That is why the amount of radiation causing 1 kg of tissue to absorb 1 joule of energy is now expressed in grays.
Different kinds of radiation can do different kinds of damage, because the energy is imparted into tissues in different ways. This is expressed in sieverts. An amount of alpha radiation can do twenty times the damage of the same amount of beta radiation. Radioactive matter has to be held in storage for different periods of time, in order to erase the danger. How long it has to be stored depends upon the half-life of the isotopes; the time taken for half of the atoms of a radioactive isotope to decay. What are the specific ways through which water pollutants enter the environment? . Domestic and industrial wastes are discharged unto surface water through sewage systems. In some cases industrial waste is released directly unto surface water. The quality of sewage water that enters the surface water depends upon the pollutants that are present in the sewage water and the extend to which it is treated before it is brought in contact with surface water. Domestic sewage water mainly consists of paper, soap, urine, faeces and detergents. Industrial wastes are varied and depend upon the specific processes of the plants that they origin from.
Heavy metals are associated with mining and smelting operations, chlorophenols and fungicides with pulp mills, insecticides with mothproofing factories, several different organic chemicals with the chemical industry and radioactive substances with nuclear power plants. On land the releases of industrial waste are closely controlled, but offshore oil and manganese extraction lead to direct discharge of pollutants into the seas. Radioactive waste is dumped into the sea in large concrete barrels to decay, but often the barrels will start to have defects after a while. Representatives of factories often ship waste onto sea to dump it illegally, because it is very expensive to have their water purified. Oil is released into the sea through oil tankers and shipwrecks and pesticides are applied to water to control aquatic pests. Paints on boats will decay during long trips on the ocean and will eventually end up in the water.
During the growth period of crops nitrates and phosphates are absorbed by plants, but when the plants die they are released from dead plant material into the soil and will often end up in surface water. Except for the deliberate causes of surface water pollution, pollutants can also enter the water environment accidentally, for instance through atmospheric deposition. Pesticides can enter surface water easily this way, because they are applied as droplets or sprays. Pollutants present on land can enter surface water through heavy rainfall or infiltrate into the soil and enter surface waters through groundwater. The effects of pollutants are noticed mostly in small inland seas and lakes. This is because the oceans have a natural dilution system for incoming pollutants, whereas lakes have no effective outlet. Due to this, much depends upon the rate of degradation and precipitation that will remove the pollutants from water. How are pollutants transported through water?
Pollutants can exist in water in different states. They can be dissolved or they can be in suspension, which means that they exist in the form of droplets or particles. Pollutants can also be dissolved in droplets or absorbed by particles. All states of pollutants can travel great distances through water in many different ways. Particulate matter may fall to the bottom of streams and lakes or rise to the surface, depending on its density. This means that it mostly remains on the same location when the water does not flow very fast. In rivers, pollutants usually travel great distances. The distance they travel depends upon the stability and physical state of the pollutant and the speed of flow of the river. Pollutants can travel farthest when they are in solution in a river that is fast flowing. The concentrations on one site are then generally low, but the pollutant can be detected on many more sites than when it would not have been so easily transported.
How do organisms respond to water pollutants?
When pollution enters the body of an organism it causes a variety of changes. These changes can either serve to protect the organism against harmful effects or not. The first response of an organism to pollutants is to bring a protective mechanism into action. In most cases these mechanisms maintain the detoxification of pollutants, but in some cases they produce active substances that can cause more damage to the cell than the original pollutant. Another response is to reduce the availability of pollutants by binding them to another molecule, to excrete or store them.
Next to protective mechanisms an organism can also bring a mechanism into action that repairs damage caused by pollutants. Responds to toxicity and the uptake of pollutants not only depends upon the pollutant that enters the organisms body, but also upon the kind of organism in question. What general effects can water pollutants have on organisms? Water pollutants can have many different effects on organisms, always depending on the pollutant and the organism in question. Here the general effects a pollutant can have are discussed.
Many compounds that enter the body of an organism are known to cause damage to DNA. These compounds are called genotoxins, due to their genotoxic effect.
Several pollutants are carcinogenic, which means they can induce cancer in the body of humans and animals. Carcinogenic pollutants are pollutants that play a role in one or more of the stages of cancer development in an organism.
The nervous system of organisms is very sensitive to toxic effects of chemicals, both naturally occurring and man-made. Chemicals that cause neurological effects are called neurotoxins. Examples of dangerous neurotoxins are insecticides.
Disturbance of energy transfer
Energy transformation in organisms is done through mitochondria systems in the cells. On the mitochondrion ATP-molecules are produced, which transfer energy through the body of an organism. When ATP production is disturbed the energy transfer will cease. This will make an organism tired and lifeless and unable to function normally.
Pollutants that cause reproductive failure due to damage to the reproductive organs are called endocrine disruptors. There are several ways in which a pollutant can act as an endocrine disruptor.
Sustainable management takes the concepts from sustainability and synthesizes them with the concepts of management. Sustainability has three branches: the environment, the needs of present and future generations, and theeconomy. Using these branches, it creates the ability to keep a system running indefinitely without depleting resources, maintaining economic viability, and also nourishing the needs of the present and future generations. From this definition, sustainable management has been created to be defined as the application of sustainable practices in the categories of businesses, agriculture, society, environment, and personal life by managing them in a way that will benefit current generations and future generations. Sustainable management is needed because it is an important part of the ability to successfully maintain the quality of life on our planet.
Sustainable management can be applied to all aspects of our lives. For example, the practices of a business should be sustainable if they wish to stay in businesses, because if the business is unsustainable, then by the definition of sustainability they will cease to be able to be in competition. Communities are in a need of sustainable management, because if the community is to prosper, then the management must be sustainable. Forest and natural resources need to have sustainable management if they are to be able to be continually used by our generation and future generations Sustainable management can be applied to many things, as it can be applied as a literal and an abstract concept. Meaning, depending on what they are applied to the meaning of what it is can change. Sustainable management is a resource management technique that seeks to make any harvesting or consumption of natural resources as sustainable as possible. Thus, the main goal is to replenish any resources as fast as they are depleted.
While this goal may not be practical,sustainable management can often help prolong the natural resource for as long as possible, such as with fossil fuels. It may be easier to sustain resources that are considered renewable, such as forests and fisheries. In order to accomplish its goal, sustainable management often looks at two different factors: the rate of consumption and the rate or replenishment. In many cases, the goal is to keep these two factors in equilibrium. In cases where there is a surplus of a resource, consumption outpacing replenishment may be possible. In most cases, this is a very real problem if a surplus does not exist. Though consumption often cannot be cut very easily, there are regulations that can promote replenishment. For example, many sustainable management policies require that forest trees be replanted if they are cut down. While this may not be the most ideal situation for the natural environment, it does help lead to a sustainable practice, especially if more than one tree is planted for each tree that is cut down.