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From Wikipedia

Agricultural pollution

Agricultural pollution comprises wastes, emissions, and discharges arising from farming activities. This includes runoff and leaching of pesticides and fertilizers; pesticide drift and volatilization; erosion and dust from cultivation; and improper disposal of animal manure and carcasses. Some agricultural pollution is point source, meaning that it is derived from a single discharge point, such as a pipe.

Large feedlots are an example of point sources. In the United States, they require permits under the Clean Water Act (P.L. 92-500, 33 U.S.C. 1251-1387). However, much of the pollution from agriculture is from nonpoint sources, meaning that it derives from dispersed origins, e.g., blowing dust or nutrients leaching from fields. Most pollution control programs have focused on particular categories of point sources, although nonpoint and unregulated point sources account for an increasingly large proportion of remaining pollution. The EPA concludes that agricultural sources account for over one-half the pollution impairing surface water quality in the U.S. based on state surveys. The Clean Water Act mandates that states develop and implement management programs to control nonpoint sources of water pollution generally, and the Coastal Zone Management Program requires participating states to develop similar programs for farms within state-designated coastal zones.

Examples

A wide range of contaminants can reach the river either via groundwater or through drainage ditches, including artificial fertilizer residues, insecticides, herbicides, pesticides and farmyard waste, all of which are potentially very harmful. Accidental milk spillage from dairies is a serious contaminant.

Undiluted animal manure (slurry) is one hundred times more concentrated than domestic sewage, and can carry a parasite, Cryptosporidium, which is difficult to detect. Silage liquor (from fermented wet grass) is even stronger than slurry, with a low pH and very high BOD (Biological Oxygen Demand). With a low pH, silage liquor can be highly corrosive; it can attack synthetic materials, causing damage to storage equipment, and leading to accidental spillage.

Milk spillage, silage liquor, cattle and pig slurry; these are all examples of non-point source pollution. Diffuse source pollution from agricultural fertilizers is more difficult to trace, monitor and control. High nitrate concentrations are found in groundwater and may reach 50mg/litre (the EU Directive limit). In ditches and river courses, nutrient pollution from fertilizers causes eutrophication. This is worse in winter, after autumn ploughing has released a surge of nitrates; winter rainfall is heavier increasing runoff and leaching, and there is lower plant uptake. Phytoplankton and algae thrive in the nutrient-rich water. Normally, blue-green algae are very important in the river ecosystem, photosynthesising sunlight energy, and liberating oxygen into the water. In large numbers, however, algae can become excessive, discolouring the water, giving an unpleasant smell and robbing the water of valuable oxygen as bacteria work overtime feeding on dead algae remains. Blue-green algae can also produce toxins, which kill wildlife, cause skin rashes, and cause pains and stomach upsets.

Eutrophication is thus depriving the river of oxygen (called "oxygen debt"). As algae dominate and turn the water green, the growth of other water plants is suppressed; these die first, disrupting the food chain. Death of invertebrates and fish follow on, and their dead remains in turn lead to excess bacterial activity during decomposition, reducing oxygen levels still further. Water with high BOD figures are badly polluted, lower figures are better.


Thermal pollution

Thermal pollution is the degradation of water quality by any process that changes ambient water temperature.

A common cause of thermal pollution is the use of water as a coolant by power plants and industrial manufacturers. When water used as a coolant is returned to the natural environment at a higher temperature, the change in temperature (a) decreases oxygen supply, and (b) affects ecosystem composition. Urban runoff--stormwater discharged to surface waters from roads and parking lots--can also be a source of elevated water temperatures.

When a power plant first opens or shuts down for repair or other causes, fish and other organisms adapted to particular temperature range can be killed by the abrupt rise in water temperature known as 'thermal shock'.

Ecological effects — warm water

Elevated temperature typically decreases the level of dissolved oxygen (DO) in water. The decrease in levels of DO can harm aquatic animals such as fish, amphibians and copepods. Thermal pollution may also increase the metabolic rate of aquatic animals, as enzyme activity, resulting in these organisms consuming more food in a shorter time than if their environment were not changed. An increased metabolic rate may result in fewer resources; the more adapted organisms moving in may have an advantage over organisms that are not used to the warmer temperature. As a result one has the problem of compromising food chains of the old and new environments. Biodiversity can be decreased as a result.

It is known that temperature changes of even one to two degrees Celsius can cause significant changes in organism metabolism and other adverse cellular biology effects. Principal adverse changes can include rendering cell walls less permeable to necessary osmosis, coagulation of cell proteins, and alteration of enzymemetabolism. These cellular level effects can adversely affect mortality and reproduction.

Primary producers are affected by warm water because higher water temperature increases plant growth rates, resulting in a shorter lifespan and species overpopulation. This can cause an algae bloom which reduces oxygen levels.

A large increase in temperature can lead to the denaturing of life-supporting enzymes by breaking down hydrogen- and disulphide bonds within the quaternary structure of the enzymes. Decreased enzyme activity in aquatic organisms can cause problems such as the inability to break down lipids, which leads to malnutrition.

In limited cases, warm water has little deleterious effect and may even lead to improved function of the receiving aquatic ecosystem. This phenomenon is seen especially in seasonal waters and is known as thermal enrichment.... An extreme case is derived from the aggregational habits of the manatee, which often uses power plant discharge sites during winter. Projections suggest that manatee populations would decline upon the removal of these discharges.

Ecological effects — cold water

Releases of unnaturally cold water from reservoirs can dramatically change the fish and macroinvertebrate fauna of rivers, and reduce river productivity. In Australia, where many rivers have warmer temperature regimes, native fish species have been eliminated, and macroinvertebrate fauna have been drastically altered.

Control of thermal pollution

Industrial wastewater
In the United States, thermal pollution from industrial sources is generated mostly by power plants, petroleum refineries, pulp and paper mills, chemical plants, steel mills and smelters. Heated water from these sources may be controlled with:

Some facilities use once-through cooling (OTC) systems which do not reduce temperature as effectively as the above systems. For example, the Potrero Generating Station in San Francisco, which uses OTC, discharges water to San Francisco Bay approximately 10°C (20°F) above the ambient bay temperature.

Urban runoff
During warm weather, urban runoff can have significant thermal

National Emissions Standards for Hazardous Air Pollutants

The National Emissions Standards for Hazardous Air Pollutants (NESHAPs) are emissions standards set by the United StatesEPA for an air pollutant not covered by NAAQS that may cause an increase in fatalities or in serious, irreversible, or incapacitating illness. The standards for a particular source category require the maximum degree of emission reduction that the EPA determines to be achievable, which is known as the Maximum Achievable Control Technology (MACT) [http://www.epa.gov/ttn/atw/112dpg.html]. These standards are authorized by Section 112 of the Clean Air Act and the regulations are published in 40 CFR Parts 61 and 63.

Pollutants

The USEPA regulates the following hazardous air pollutants via the MACT standards:

For all listings above which contain the word "compounds" and for glycol ethers, the following applies: Unless otherwise specified, these listings are defined as including any unique chemical substance that contains the named chemical (i.e., antimony, arsenic, etc.) as part of that chemical's infrastructure.

  • X'CN where X = H' or any other group where a formal dissociation may occur. For example KCN or Ca(CN)2
  • Includes mono- and di- ethers of ethylene glycol, diethylene glycol, and triethylene glycol R-(OCH2CH2)n -OR' where
n = 1, 2, or 3
R = alkyl C7 (chain of 7 carbon atoms) or less; or phenyl or alkyl substituted phenyl
R' = H or alkyl C7 or less; or OR' consisting of carboxylic acid ester, sulfate, phosphate, nitrate, or sulfonate. Polymers are excluded from the glycol category, as well as surfactant alcohol ethoxylates (where R is an alkyl C8 or greater) and their derivatives, and ethylene glycol monobutyl ether (CAS 111-76-2).
  • Includes mineral fiber emissions from facilities manufacturing or processing glass, rock, or slag fibers (or other mineral derived fibers) of average diameter 1 micrometer or less.
  • Includes organic compounds with more than one benzene ring, and which have a boiling point greater than or equal to 100 Â°C.
  • A type of atom which spontaneously undergoes radioactive decay.

Sources: [http://www.epa.gov/ttn/atw/orig189.html USEPA's original list] & [http://www.epa.gov/ttn/atw/pollutants/atwsmod.html Modifications]

Pollution sources

Most air toxics originate from human-made sources, including mobile sources (e.g., cars, trucks, buses) and stationary sources (e.g., factories, refineries, power plants), as well as indoor sources (e.g., building materials and activities such as cleaning). There are two types of stationary sources that generate routine emissions of air toxics:

"Major" sources are defined as sources that emit 10 tons per year of any of the listed toxic air pollutants, or 25 tons per year of a mixture of air toxics. These sources may release air toxics from equipment leaks, when materials are transferred from one location to another, or during discharge through emission stacks or vents

"Area" sources consist of smaller-size facilities that release lesser quantities of toxic pollutants into the air. Area sources are defined as sources that emit less than 10 tons per year of a single air toxic, or less than 25 tons per year of a combination of air toxics. Though emissions from individual area sources are often relatively small, collectively their emissions can be of concern - particularly where large numbers of sources are located in heavily populated areas.

The United States EPA published the initial list of "source categories" in 1992 (57FR31576, July 16, 1992) and since that time has issued several revisions and updates to the list and promulgation schedule. For each listed source category, EPA indicates whether the sources are considered to be "major" sources or "area" sources. The 1990 Clean Air Act Amendments direct EPA to set standards for all major sources of air toxics (and some area sources that are of particular concern). [http://www.epa.gov/ttn/atw/pollsour.html]



From Encyclopedia

Attenuation of Pollutants Attenuation of Pollutants

The moment that pollutants in soils become dissolved in natural waters, their potential for transport is greatly magnified, as is the likelihood that people will ingest them. The primary health risk from many hazardous waste sites, dumps, septic tanks, factory outflows, and other pollution sources is the possibility that pollutants will be dissolved into groundwaters or surface waters, then ultimately reach drinking water. Pollutants of concern include industrial solvents such as perchlorethlyene (PCE); trichlorethylene (TCE); motor fuel components such as benzene, toluene, ethylbenzene, and xylene, (collectively termed BTEX); and inorganic contaminants such as lead, chromate, arsenic, and nitrate. Just as each contaminant tends to affect specific organs in the human body depending on its chemistry, the behavior of contaminants in groundwaters and surface waters likewise varies from contaminant to contaminant. Rarely do chemicals behave identically in natural waters; typically there is at least one natural reaction that causes the bioavailability of a given contaminant to decrease, or attenuate, over time. These attenuation reactions include the following. Contaminant attenuation can be split into two components. Organic contaminants are made up of electron-rich molecules containing linked carbon atoms. Soil microorganisms can derive energy by using oxygen, sulfate, nitrate, or ferrous iron to oxidize and break these chains down into carbon dioxide plus water. Often this breakdown is more rapid than engineered remediation. Rapid microbial attenuation is often observed for fuel hydrocarbons such as are found beneath leaking underground fuel tanks. Attenuation tends to be most rapid under oxidizing (aerobic ) conditions that often prevail in loose soils. In oxygen-poor (anaerobic ) waters, attenuation tends to be slower. PCE and TCE are two of the most common contaminants at hazardous waste sites. They are quite toxic and also tend to resist chemical attenuation. Microorganisms are only able to rapidly attenuate them by first reducing them under anaerobic conditions, and then oxidizing them under aerobic conditions. Obviously the potential for PCE or TCE attenuation hinges upon the chemical condition of the aquifer or soil. Chemical attenuation of inorganic contaminants such as lead, chromate, nitrate, and arsenic often involves sorption onto mineral surfaces. Microorganisms generally cannot break down such contaminants into less toxic compounds except in a few cases. Most notably, microorganisms are able to reduce oxidized (and toxic) chromate to insoluble and less toxic trivalent chromium. Likewise, microorganisms can convert nitrate to ammonia and/or nitrogen gas. Most other inorganic contaminants must be sorbed to mineral surfaces to be attenuated. Soil and aquifer solids tend to be negatively charged because of broken or unsatisfied bonds that exist at their surfaces. This negative charge that exists at mineral surfaces pulls oppositely charged cations from solution. Many dissolved metals exist as positively charged cations in natural waters and are hence attracted to, and attenuated at, mineral surfaces. This is particularly true for such industrial metals as lead, cadmium, zinc, and nickel. It is also true for such important radionuclides that are present in radioactive waste as 90Sr, 137Cs, and isotopes of Pu (plutonium) and U (uranium). Chromate and arsenate sorb appreciably to many soil minerals despite the overall negative charge of both partners. Inorganic contaminants that initially sorb onto mineral surfaces from a contaminant-rich solution might in theory "desorb" back into contaminantpoor waters recharging a contaminated aquifer after the contaminant source has been removed. In fact, numerous field observations suggest that many sorbed contaminants become permanently sequestered after prolonged interaction with mineral surfaces. In other words, sorbed contaminants are taken up into mineral lattices (structures) where they are no longer bioavailable. Mineral uptake also makes the complete engineered removal of contaminants from soils and aquifers nearly impossible. In effect, the crystal lattices must be destroyed to remove the bound contaminants. Pollutant attenuation is most commonly taken advantage of in the treatment of sewage; that is, oxidation of organic matter is hastened by mixing on-site or by discharging into surface waters that have sufficient capacity to rapidly attenuate the imposed pollutant load. Increasingly, pollutant attenuation, or equivalently "monitored natural attenuation" or MNA, is being used as a component of hazardous waste site cleanups. Specifically, MNA is relied upon to remove contaminants from groundwaters, in parallel to and, after active remediation has ceased. Bioremediation of contaminated sites typically involves the engineered acceleration of natural organic activity that leads to the breakdown of organic contaminants—most commonly spilled fuels and solvents—ultimately to carbon dioxide. Less common is the introduction of new organisms, themselves, to contaminated sites. Natural soil organic activity tends to be sufficiently pervasive that, given the appropriate nutrients, breakdown of contaminants can be achieved by native populations of microorganisms. Nutrient additions may include oxygen, a carbon substrate such as molasses, and/or hydrogen. It must be noted that not all contaminants attenuate rapidly enough to prevent potential impacts on human health. Instead, knowledge of attenuation rates and capacities is critical to the successful implementation of pollutant attenuation in either realm. Each area remains the subject of intense investigation by chemists, biologists, geochemists, engineers, and other scientists. see also Fresh Water, Natural Composition of; Fresh Water, Physics and Chemistry of; Groundwater; Modeling Groundwater Flow and Transport; Modeling Stream Flow and Quality; Pollution of Groundwater; Pollution of Lakes and Streams; Radioactive Chemicals; Septic System Impacts; Wastewater Treatment and Management. Patrick V. Brady Brady, Patrick V., Michael V. Brady, and David J. Borns. Natural Attenuation: CERCLA, RBCAs, and the Future of Environmental Remediation. Boca Raton, FL: Lewis Publishers, 1997. Rice, David W. et al. "Recommendations to Improve the Cleanup Process for California's Leaking Underground Fuel Tanks." In Lawrence Livermore National Laboratory Report. Lawrence Livermore National Laboratory, CA: 1995.


From Yahoo Answers

Question:i hav got my chemistry project... its air pollution... can sumone plss tell me what all contents shud it hav (related to chemistry too) and then everybody in the class wud be referring internet for their information... plss can sum one tell me good books where i can find more about this and good links too tht my frndss cant reach to... thnxxx

Answers:Introduction - When people think about air pollution, they usually think about smog, acid rain, CFC's, and other forms of outdoor air pollution. But did you know that air pollution also can exist inside homes and other buildings? It can, and every year, the health of many people is affected by chemical substances present in the air within buildings. A great deal of research on pollution is being conducted at laboratories and universities. The goals of the research are to find solutions and to educate the public about the problem. Two places where this type of work is being done are LBNL and the University of California, Berkeley. Let's take a closer look at the various types of air pollution, the effects that they have on people, and what is being (or not being) done to correct the problem. What is Air Pollution?- Air is the ocean we breathe. Air supplies us with oxygen which is essential for our bodies to live. Air is 99.9% nitrogen, oxygen, water vapor and inert gases. Human activities can release substances into the air, some of which can cause problems for humans, plants, and animals. There are several main types of pollution and well-known effects of pollution which are commonly discussed. These include smog, acid rain, the greenhouse effect, and "holes" in the ozone layer. Each of these problems has serious implications for our health and well-being as well as for the whole environment. One type of air pollution is the release of particles into the air from burning fuel for energy. Diesel smoke is a good example of this particulate matter . The particles are very small pieces of matter measuring about 2.5 microns or about .0001 inches. This type of pollution is sometimes referred to as "black carbon" pollution. The exhaust from burning fuels in automobiles, homes, and industries is a major source of pollution in the air. Some authorities believe that even the burning of wood and charcoal in fireplaces and barbeques can release significant quanitites of soot into the air. Another type of pollution is the release of noxious gases, such as sulfur dioxide, carbon monoxide, nitrogen oxides, and chemical vapors. These can take part in further chemical reactions once they are in the atmosphere, forming smog and acid rain. Pollution also needs to be considered inside our homes, offices, and schools. Some of these pollutants can be created by indoor activities such as smoking and cooking. In the United States, we spend about 80-90% of our time inside buildings, and so our exposure to harmful indoor pollutants can be serious. It is therefore important to consider both indoor and outdoor air pollution. Outdoor Air Pollution- Smog is a type of large-scale outdoor pollution. It is caused by chemical reactions between pollutants derived from different sources, primarily automobile exhaust and industrial emissions. Cities are often centers of these types of activities, and many suffer from the effects of smog, especially during the warm months of the year. Additional information about smog and its effects are available from Environment Canada and the Air Quality Management District (AQMD) in southern California. For each city, the exact causes of pollution may be different. Depending on the geographical location, temperature, wind and weather factors, pollution is dispersed differently. However, sometimes this does not happen and the pollution can build up to dangerous levels. A temperature inversion occurs when air close to the earth is cooler than the air above it. Under these conditions the pollution cannot rise and be dispersed. Cities surrounded by mountains also experience trapping of pollution. Inversion can happen in any season. Winter inversions are likely to cause particulate and cabon monoxide pollution. Summer inversions are more likely to create smog. Another consequence of outdoor air pollution is acid rain. When a pollutant, such as sulfuric acid combines with droplets of water in the air, the water (or snow) can become acidified . The effects of acid rain on the environment can be very serious. It damages plants by destroying their leaves, it poisons the soil, and it changes the chemistry of lakes and streams. Damage due to acid rain kills trees and harms animals, fish, and other wildlife. The U.S. Geological Survey (USGS), the Environmental Protection Agency (EPA), and Environment Canada are among the organizations that are actively studying the acid rain problem. The Greenhouse Effect, also referred to as global warming, is generally believed to come from the build up of carbon dioxide gas in the atmosphere. Carbon dioxide is produced when fuels are burned. Plants convert carbon dioxide back to oxygen, but the release of carbon dioxide from human activities is higher than the world's plants can process. The situation is made worse since many of the earth's forests are being removed, and plant life is being damaged by acid rain. Thus, the amount of carbon dioxide in the air is continuing to increase. This buildup acts like a blanket and traps heat close to the surface of our earth. Changes of even a few degrees will affect us all through changes in the climate and even the possibility that the polar ice caps may melt. (One of the consequences of polar ice cap melting would be a rise in global sea level, resulting in widespread coastal flooding.) Additional resources and information about the Greenhouse Effect and global warming are available from the Environmental Defense Fund (EDF), the Science Education Academy of the Bay Area (SEABA) and the Society of Environmental Journalists (SEJ). Ozone depletion is another result of pollution. Chemicals released by our activities affect the stratosphere , one of the atmospheric layers surrounding earth. The ozone layer in the stratosphere protects the earth from harmful ultraviolet radiation from the sun. Release of chlorofluorocarbons (CFC's) from aerosol cans, cooling systems and refrigerator equipment removes some of the ozone, causing "holes"; to open up in this layer and allowing the radiation to reach the earth. Ultraviolet radiation is known to cause skin cancer and has damaging effects on plants and wildlife. Additional resources and information about the ozone depletion problem are available from the National Oceanic and Atmospheric Administration (NOAA) and Ozone ACTION. Indoor Air Pollution- Many people spend large portion of time indoors - as much as 80-90% of their lives. We work, study, eat, drink and sleep in enclosed environments where air circulation may be restricted. For these reasons, some experts feel that more people suffer from the effects of indoor air pollution than outdoor pollution. There are many sources of indoor air pollution. Tobacco smoke, cooking and heating appliances, and vapors from building materials, paints, furniture, etc. cause pollution inside buildings. Radon is a natural radioactive gas released from the earth, and it can be found concentrated in basements in some parts of the United States. Additional information about the radon problem is available from the USGS and the Minnesota Radon Project. Pollution exposure at home and work is often greater than outdoors. The California Air Resources Board estimates that indoor air pollutant levels are 25-62% greater than outside levels and can pose serious health problems. Both indoor and outdoor pollution need to be controlled and/or prevented. How can we prevent the damaging effects of air pollution? How can air pollution hurt my health? Health Effects- Air pollution can affect our health in many ways with both short-term and long-term effects. Different groups of individuals are affected by air pollution in different ways. Some individuals are much more sensitive to pollutants than are others. Young children and elderly people often suffer more from the effects of air pollution. People with health problems such as asthma, heart and lung disease may also suffer more when the air is polluted. The extent to which an individual is harmed by air pollution usually depends on the total exposure to the damaging chemicals, i.e., the dur

Question:

Answers:Carbon-14: Archaeological dating Americium-241: Smoke detectors Cobalt-60: Food Irradiation Phosphorus-32: Biology study

Question:Nuclear 1. State one possible advantage of using nuclear pwr instead of burning fossil fuels. 2. State one risk of using nuclear pwr. 3. Explain how a nuclear reaction is diff from a chemical reaction. Radioactivity 1. Nuclear equation for the decay of C-14 2. Why N-16 is a poor choice for radioactive dating in bone. 3. Sampe of wood is found to contain 1/8 as much C-14 as is present in the wood of a living tree. What is the age of the wood? thankyou

Answers:1. Its cleaner. It produces a very small volume of waste that doesn't pollute the air like burning hydrocarbons does. 2. Theres always that slight risk that radiation somehow leaked from the spent fuel could harm someone 3. In a nuclear reaction, changes in the nucleus of the elements occur, as oppose to the electrons as in a chemical reaction 1. C14 -> N14 + e-(beta particle) 2. It has a half life on the order of seconds 3. About 22920 years

Question:I only need one, really...but I like options. I also need to draw it(Comic assignment), and I have very little artistic talent.

Answers:" Organic Industries" "Automobiles" are two of the Major Factors in Air Pollution. "Camp Fires are Probably the last on the "Totem Pole" of Air Pollution.

From Youtube

Radioactive Decay Simplified :A simple quantitative example to illustrate the behavior of radioactive decay. This illustrates the general principle used by professional scientists to determine the ages of everything from remains at an acheological dig to the Earth itself.

Rate of radioactive decay: A worked example to calculate the half life of an isotope :This worked example shows step by step, how to calculate the half life of an isotope. Calculating the half-life of a radioactive isotope has many applications not just in chemistry but in physics, environmental science and medicine. The worked example shows how easy it is to use the intergrated first order rate law in order to find the half life of an isotope...