Noise pollution - sources, effects and control measures; radio active, thermal and nuclear pollution

Noise pollution is excessive, displeasing human, animal or machine-created environmental noise that disrupts the activity or balance of human or animal life. The word noise comes from the Latin word nauseas, meaning seasickness.

Sources

The noise pollution has two sources, i.e. industrial and non- industrial. The industrial source includes the noise from various industries and big machines working at a very high speed and high noise intensity. Non-industrial source of noise includes the noise created by transport/vehicular traffic and the neighborhood noise generated by various noise pollution can also be divided in the categories, namely, natural and manmade. Most leading noise sources will fall into the following categories: roads traffic, aircraft, railroads, construction, industry, noise in buildings, and consumer products

1. Road Traffic Noise:- In the city, the main sources of traffic noise are the motors and exhaust system of autos, smaller trucks, buses, and motorcycles. This type of noise can be augmented by narrow streets and tall buildings, which produce a canyon in which traffic noise reverberates.

2. Air Craft Noise: - Now-a-days , the problem of low flying military aircraft has added a new dimension to community annoyance, as the nation seeks to improve its nap-of the-earth aircraft operations over national parks, wilderness areas, and other areas previously unaffected by aircraft noise has claimed national attention over recent years.

3. Noise from railroads:- The noise from locomotive engines, horns and whistles, and switching and shunting operation in rail yards can impact neighboring communities and railroad workers. For example, rail car retarders can produce a high frequency, high level screech that can reach peak levels of 120 dB at a distance of 100 feet, which translates to levels as high as 138, or 140 dB at the railroad worker’s ear.

4. Construction Noise:-The noise from the construction of highways, city streets, and buildings is a major contributor to the urban scene. Construction noise sources include pneumatic hammers, air compressors, bulldozers, loaders, dump trucks (and their back-up signals), and pavement breakers.

5. Noise in Industry: - Although industrial noise is one of the less prevalent community noise problems, neighbors of noisy manufacturing plants can be disturbed by sources such as fans, motors, and compressors mounted on the outside of buildings Interior noise can also be transmitted to the community through open windows and doors, and even through building walls. These interior noise sources have significant impacts on industrial workers, among whom noise- induced hearing loss is unfortunately common.

6. Noise in building: - Apartment dwellers are often annoyed by noise in their homes, especially when the building is not well designed and constructed. In this case, internal building noise from plumbing, boilers, generators, air conditioners, and fans, can be audible and annoying. Improperly insulated walls and ceilings can reveal the sound of-amplified music, voices, footfalls and noisy activities from neighboring units. External noise from emergency vehicles, traffic, refuse collection, and other city noises can be a problem for urban residents, especially when windows are open or insufficiently glazed.

7. Noise from Consumer products:- Certain household equipment, such as vacuum cleaners and some kitchen appliances have been and continue to be noisemakers, although their contribution to the daily noise dose is usually not very large.

Effects

Human health

Noise health effects are both health and behavioral in nature. The unwanted sound is called noise. This unwanted sound can damage physiological and psychological health. Noise pollution can cause annoyance and aggression, hypertension, high stress levels, tinnitus, hearing loss, sleep disturbances, and other harmful effects. Furthermore, stress and hypertension are the leading causes to health problems, whereas tinnitus can lead to forgetfulness, severe depression and at times panic attacks.

High noise levels can contribute to cardiovascular effects and exposure to moderately high levels during a single eight hour period causes a statistical rise in blood pressure of five to ten points and an increase in stress and vasoconstriction leading to the increased blood pressure noted above as well as to increased incidence of coronary artery disease.

Wildlife health

Noise can have a detrimental effect on animals, increasing the risk of death by changing the delicate balance in predator or prey detection and avoidance, and interfering the use of the sounds in communication especially in relation to reproduction and in navigation. Acoustic overexposure can lead to temporary or permanent loss of hearing.

An impact of noise on animal life is the reduction of usable habitat that noisy areas may cause, which in the case of endangered species may be part of the path to extinction. Noise pollution has caused the death of certain species of whales that beached themselves after being exposed to the loud sound of military sonar.

Noise also makes species communicate louder, which is called Lombard vocal response. Scientists and researchers have conducted experiments that show whales' song length is longer when submarine-detectors are on. If creatures do not "speak" loud enough, their voice will be masked by anthropogenic sounds. These unheard voices might be warnings, finding of prey, or preparations of net-bubbling. When one species begins speaking louder, it will mask other species' voice, causing the whole ecosystem to eventually speak louder.

European Robins living in urban environments are more likely to sing at night in places with high levels of noise pollution during the day, suggesting that they sing at night because it is quieter, and their message can propagate through the environment more clearly. The same study showed that daytime noise was a stronger predictor of nocturnal singing than night-time light pollution, to which the phenomenon is often attributed.

Zebra finches become less faithful to their partners when exposed to traffic noise. This could alter a population's evolutionary trajectory by selecting traits, sapping resources normally devoted to other activities and thus lead to profound genetic and evolutionary consequences.

Mitigation and control of noise

There are a variety of strategies for mitigating roadway noise including: use of noise barriers, limitation of vehicle speeds, alteration of roadway surface texture, limitation of heavy vehicles, use of traffic controls that smooth vehicle flow to reduce braking and acceleration, and tire design.

Aircraft noise can be reduced to some extent by design of quieter jet engines, which was pursued vigorously in the 1970s and 1980s. This strategy has brought limited but noticeable reduction of urban sound levels. Reconsideration of operations, such as altering flight paths and time of day runway use, has demonstrated benefits for residential populations near airports.

Industrial noise can be controlled by redesign of industrial equipment, shock mounting assemblies and physical barriers in the workplace.

Radio active , thermal and nuclear pollution

Sources of waste

Radioactive waste comes from a number of sources. The majority of waste originates from the nuclear fuel cycle and nuclear weapons reprocessing. However, other sources include medical and industrial wastes, as well as naturally occurring radioactive materials (NORM) that can be concentrated as a result of the processing or consumption of coal, oil and gas, and some minerals.

Nuclear fuel cycle

Front end

Waste from the front end of the nuclear fuel cycle is usually alpha-emitting waste from the extraction of uranium. It often contains radium and its decay products.

Uranium dioxide (UO₂) concentrate from mining is not very radioactive - It is refined from yellowcake (U₃O₈), then converted to uranium hexafluoride gas (UF₆). As a gas, it undergoes enrichment to increase the U-235 content from 0.7% to about 4.4% (LEU). It is then turned into a hard ceramic oxide (UO₂) for assembly as reactor fuel elements.

Back end

The back end of the nuclear fuel cycle, mostly spent fuel rods, contains fission products that emit beta and gamma radiation, and actinides that emit alpha particles, such as uranium-234, neptunium-237, plutonium-238 and americium-241, and even sometimes some neutron emitters such as californium (Cf). These isotopes are formed in nuclear reactors.

Medical

Radioactive medical waste tends to contain beta particle and gamma ray emitters. It can be divided into two main classes.

In diagnostic nuclear medicine a number of short-lived gamma emitters such as technetium-99m are used. Many of these can be disposed of by leaving it to decay for a short time before disposal as normal waste. For treatment isotopes used in medicine, with half-lives in parentheses, include:

§  Y-90, used for treating lymphoma (2.7 days)

§  I-131, used for thyroid function tests and for treating thyroid cancer (8.0 days)

§  Sr-89, used for treating bone cancer, intravenous injection (52 days)

§  Ir-192, used for brachytherapy (74 days)

§  Co-60, used for brachytherapy and external radiotherapy (5.3 years)

§  Cs-137, used for brachytherapy, external radiotherapy (30 years)

Industrial

Industrial source waste can contain alpha, beta, neutron or gamma emitters. Gamma emitters are used in radiography while neutron emitting sources are used in a range of applications, such as oil well logging.

Naturally occurring radioactive material (NORM)

Coal

Coal contains a small amount of radioactive uranium, barium, thorium and potassium. The more active ash minerals become concentrated in the fly ash precisely because they do not burn well. The radioactivity of fly ash is about the same as black shale and is less than phosphate rocks.

Oil and gas

Residues from the oil and gas industry often contain radium and its daughters. The sulfate scale from an oil well can be very radium rich, while the water, oil and gas from a well often contain radon. The radon decays to form solid radioisotopes which form coatings on the inside of pipework.

Prevention of waste

·         The one way of preventing some of radioactive waste is the phasing out of nuclear power generation, and replacing it renewable energy sources such as wind power, solar power, Wave power and geothermal power. Germany is the first major industrialized country to adopt this policy.

·         phase out current reactors in favour of Generation IV Reactors or Liquid Fluoride Thorium Reactors, which output less waste per power generated. Fast reactors can theoretically consume some existing waste,

Management of waste

·         Of particular concern in nuclear waste management are two long-lived fission products, Tc-99 (half-life 220,000 years) and I-129 (half-life 17 million years), which dominate spent fuel radioactivity after a few thousand years. The most troublesome transuranic elements in spent fuel are Np-237 (half-life two million years) and Pu-239 (half-life 24,000 years). Nuclear waste requires sophisticated treatment and management to successfully isolate it from interacting with the biosphere. This usually necessitates treatment, followed by a long-term management strategy involving storage, disposal or transformation of the waste into a non-toxic form.

Initial treatment of waste

Vitrification

Long-term storage of radioactive waste requires the stabilization of the waste into a form which will neither react nor degrade for extended periods of time. One way to do this is through vitrification. Currently at Sellafield the high-level waste (PUREX first cycle raffinate) is mixed with sugar and then calcined. Calcination involves passing the waste through a heated, rotating tube. The purposes of calcination are to evaporate the water from the waste, and de-nitrate the fission products to assist the stability of the glass produced.

Ion exchange

It is common for medium active wastes in the nuclear industry to be treated with ion exchange or other means to concentrate the radioactivity into a small volume. The much less radioactive bulk (after treatment) is often then discharged. For instance, it is possible to use a ferrichydroxide floc to remove radioactive metals from aqueous mixtures.^[38] After the radioisotopes are absorbed onto the ferric hydroxide, the resulting sludge can be placed in a metal drum before being mixed with cement to form a solid waste form.^[39] In order to get better long-term performance (mechanical stability) from such forms, they may be made from a mixture of fly ash, or blast furnace slag, and Portland cement, instead of normal concrete (made with Portland cement, gravel and sand).

Synroc

The Australian Synroc (synthetic rock) is a more sophisticated way to immobilize such waste, and this process may eventually come into commercial use for civil wastes. The Synroc contains pyrochlore and cryptomelane type minerals. The original form of Synroc (Synroc C) was designed for the liquid high level waste (PUREX raffinate) from a light water reactor. The main minerals in this Synroc are hollandite (BaAl₂Ti₆O₁₆), zirconolite (CaZrTi₂O₇) and perovskite (CaTiO₃). The zirconolite and perovskite are hosts for the actinides. Thestrontium and barium will be fixed in the perovskite. The caesium will be fixed in the hollandite.

Long term management of waste

1.   Above-ground disposal

2.   Geologic disposal

3.   Transmutation

4.   Re-use of waste

5.   Space disposal

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 

Sources:

1. Power plants (75 to 82 percent)

2. Industrial manufacturers

o        petroleum refineries

o        pulp and paper mills

o        chemical plants

o        steel mills and smelters

3. Urban runoff–stormwater 

4. cold water from reservoirs 

 

Ecological effects

Warm water

Elevated temperature typically decreases the level of dissolved oxygen in water. This can harm aquatic animals such as fish, amphibians and other aquatic organisms. 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, food chains of the old and new environments may be compromised. Some fish species will avoid stream segments or coastal areas adjacent to a thermal discharge. Biodiversity can be decreased as a result.

High temperature limits oxygen dispersion into deeper waters, contributing to anaerobic conditions. This can lead to increased anaerobic bacterial fermentation  levels when there is ample food supply. Many aquatic species will fail to reproduce at elevated temperatures.

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.

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 enzyme metabolism. These cellular level effects can adversely affect mortality and reproduction.

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.

Cold water

Releases of unnaturally cold water from reservoirs can dramatically change the fish and macroinvertebrate fauna of rivers, and reduce river productivity.

Control of thermal pollution

Industrial wastewater

cooling ponds, man-made bodies of water designed for cooling by evaporation, convection, and radiation

§  cooling towers, which transfer waste heat to the atmosphere through evaporation and/or heat transfer

§  cogeneration, a process where waste heat is recycled for domestic and/or industrial heating purposes.

Urban runoff

During warm weather, urban runoff can have significant thermal impacts on small streams, as stormwater passes over hot parking lots, roads and sidewalks. Stormwater management facilities that absorb runoff or direct it into groundwater, such as bioretention systems and infiltration basins, can reduce these thermal effects. 

Nuclear pollution

Man made nuclear pollution takes place by nuclear explosions

Nuclear wastes disposal

Nuclear power plant

Use of radioactive rays to certain purposes.

1- Nuclear Explosions

A nuclear explosion causes both immediate radiation and residual radiation. Immediate radiation is given right now the explosion. It is dangerous only within two or three kilometers. If a living organism is near the explosion without adequate protection and managed to survive the effects of blast and fire, it can dramatically damaged by the immediate radiation.

Residual radiation is given off by the radioactive particles left as "fallout" after the explosion. The danger from fallout would be so great and widespread that it is discussed separately. This radioactive material is then carried by winds until it settles to earth. This is called "Fallout". Under some circumstances you may see the fallout; under others you may not. The radioactivity it gives off cannot be seen and it has no smell. But fallout doesn't come out of the sky like a gas and seep into everything. It can best be  described as a fine to coarse sand carried by the winds. Because the wind direction varies at different heights above the ground, it is not possible to judge from the ground where the fallout will settle. It can settle in irregular patterns hundreds of miles from the explosion.

The fallout from a 5-megaton explosion could affect seriously an area of 7,000 square miles. If nothing were done to gain protection during the period of high radioactivity, there would be a grave danger to life in that area.

Nuclear pollution was realized by human kind as holastic threat when First World War at first and second Atom Bombs. After the bombing the effects were going on and millions of Japan people had suffered from mutation. Many baybies borned with biological faults and many people has suffered from cancer illnesses.

Nuclear Pollution by Chernobyl Accident effected the Black Sea region of Turkey, and cause many ecological decomposition. Even today many scientists say about the Chernobyl Accident is responsible to Cancer ratios at Black Sea region of Turkey.

 Nuclear activities not only occur due to humans but also occur by naturally.

In nature, radioactive decay results from three main sources: some primordial nuclides are radioactive, but are so long-lived that they remain present from the primordial solar nebula. Other naturally-occurring radionuclides are short-lived radiogenic nuclides that are the daughters of these radiactive primordial nuclides. A third source of naturally-occurring radioactive nuclides are cosmogenic nuclides, formed by cosmic ray bombardment of material in the Earth's atmosphere or crust.