Sources of noise

^{the overarching source of most noise worldwide is generated by transportation systems, principally motor vehicle noise, but also including aircraft noise and rail noise. Hybrid vehicles are the first innovation within the last 100 years to achieve significant widespread noise source reduction.[citation needed] Poor urban planning may also give rise to noise pollution, since juxtaposition of industrial to residential land uses, for example, often results in adverse consequences for the residential acoustic environment.}

^{Besides transportation noise, other prominent sources are office equipment, factory machinery, appliances, power tools, lighting hum and audio entertainment systems. Furthermore, with the popularity of digital audio player devices, individuals in a noisy area might increase the volume in order to drown out ambient sounds. Construction equipment also produces noise pollution.}

^{Noise from recreational vehicles has become a serious problem in rural areas. ATVs, also known as quads, have increased in popularity and are joining the traditional two wheeled dirt motorcycles for off-road riding. The noise produced by these vehicles is particularly disturbing due to the wide variations in frequency and volume.}

^{Human health}

^{Principal noise health effects are both health and behavioral in nature. The following discussion refers to sound levels that are present within 30 to 150 meters from a moderately busy highway. Sound is a particular auditory impression perceived by the sense of hearing. The presence of unwanted sound is called noise pollution. This unwanted sound can seriously damage and affect physiological and psychological health. For instance, noise pollution can cause annoyance and aggression, hypertension, high stress levels, tinnitus, hearing loss, and other harmful effects depending on the level of sound, or how loud it is. Furthermore, stress and hypertension are the leading causes to health problems, whereas tinnitus can lead to forgetfulness, severe depression and at times panic attacks.}

  ^Hearing

^{The mechanism for chronic exposure to noise leading to hearing loss is well established. The elevated sound levels cause trauma to the cochlear structure in the inner ear, which gives rise to irreversible hearing loss. A very loud sound in a particular frequency range can damage the cochlea’s hair cells that respond to that range thereby reducing the ear’s ability to hear those frequencies in the future. However, loud noise in any frequency range has deleterious effects across the entire range of human hearing.}

^{The outer ear (visible portion of the human ear) combined with the middle ear amplifies sound levels by a factor of 20 when sound reaches the inner ear.}

^{In Rosen’s seminal work on serious health effects regarding hearing loss, one of his findings derived from tracking Maaban tribesmen, who were insignificantly exposed to transportation or industrial noise. This population was systematically compared by cohort group to a typical U.S. population. The findings proved that aging is an almost insignificant cause of hearing loss, which instead is associated with chronic exposure to moderately high levels of environmental noise.}

 ^{Cardiovascular health}

^{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 a clear and measurable increase in stress and vasoconstriction leading to the increased blood pressure noted above as well as to increased incidence of coronary artery disease.}

 ^Annoyance

^{Though it pales in comparison to the health effects noted above, noise pollution constitutes a significant factor of annoyance and distraction in modern artificial environments:}

1. ^{The meaning listeners attribute to the sound influences annoyance, so that, if listeners dislike the noise content, they are annoyed. What is music to one is noise to another.}
2. ^{If the sound causes activity interference, noise is more likely to annoy (for example, sleep disturbance)}
3. ^{If listeners feel they can control the noise source, the noise is less likely to be annoying.}
4. ^{If listeners believe that the noise is subject to third-party control, including police, but control has failed, they are more annoyed.}
5. ^{The inherent unpleasantness of the sound causes annoyance.}
6. ^{Contextual sound. If the sound is appropriate for the activity it is in context. If one is at a race track the noise is in context and the psychological effects are absent. If one is at an outdoor picnic the race track noise will produce adverse psychological and physical effects.}

^{A 2005 study by Spanish researchers found that in urban areas households are willing to pay approximately four Euros per decibel per year for noise reduction.}

 ^Environment

^{Noise and other loud sounds can have a detrimental effect on animals by causing stress, increasing risk of mortality by changing the delicate balance in predator/prey detection and avoidance, and by interfering with their use of sounds in communication especially in relation to reproduction and in navigation. Very significantly, acoustic overexposure can lead to temporary or permanent loss of hearing.}

^{Habitat reduction}

^{The most significant impact of noise to animal life is the systematic reduction of usable habitat, which in the case of endangered species may be an important part of the path to extinction. Perhaps the most sensational damage caused by noise pollution is the death of certain species of beached whales, brought on by the extremely loud (up to 200 decibels) sound of military sonar.}

 ^{Lombard vocal response}

^{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-detecters are on. If creatures don’t “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.}

 ^{Other habit changes}

^{Ships may be mistaken by creatures for their predator and of course, either protect themselves, attack, or run away. If they attack, humans might have financial loss, but running away will have an even more deadly result. After they run away several times, it will become part of its habit and start ignoring it. When their natural predators come, they will stay and think that it’s the boat.}

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

 ^{Mitigation and control of noise}

^{The sound tube in Melbourne, Australia, designed to reduce roadway noise without detracting from the area’s aesthetics.}

^{There is also technology that has been applied with the aim of mitigating or containing noise as much as possible, provided that it has a sufficiently localized source.}

• ^{Roadway noise is the most widespread environmental component of noise pollution worldwide. There are a variety of effective strategies for mitigating adverse sound levels including: use of noise barriers, limitation of vehicle speeds, alteration of roadway surface texture, limitation of heavy duty vehicles, use of traffic controls that smooth vehicle flow to reduce braking and acceleration, innovative tire design and other methods. Thousands of case studies in the U.S. alone have been documented starting in 1970, indicating substantial improvement in roadway planning and design. The most important factor in applying these strategies is a computer model for roadway noise, that is capable of addressing local topography, meteorology, traffic operations and hypothetical mitigation. Costs of building in mitigation is often quite modest, provided these solutions are sought in the planning stage of a roadway project.}
• ^{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, have demonstrated significant benefits for residential populations near airports. FAA sponsored residential retrofit (insulation) programs initiated in the 1970s has also enjoyed widespread success in reducing interior residential noise in thousands of affected residences across the United States.}
• ^{Exposure of Industrial noise on workers has the longest history of scientific study, having been addressed since the 1930s. This scientific studies have emphasized redesign of industrial equipment, shock mounting assemblies and physical barriers in the workplace. Innovations have had considerable success; however, the costs of retrofitting existing systems is often rather high.}

 ^{Legal status}

^{Governments up until the 1970s viewed noise as a “nuisance” rather than an environmental problem. In the United States there are federal standards for highway and aircraft noise; states and local governments typically have very specific statutes on building codes, urban planning and roadway development. In Canada and the EU there are few national, provincial, or state laws that protect against noise.}

^{Noise laws and ordinances vary widely among municipalities and indeed do not even exist in some cities. An ordinance may contain a general prohibition against making noise that is a nuisance, or it may set out specific guidelines for the level of noise allowable at certain times of the day and for certain activities.}

^{Most city ordinances prohibit sound above a threshold intensity from trespassing over property line at night, typically between 10 p.m. and 6 a.m., and during the day restricts it to a higher decibel level; however, enforcement is uneven. Many municipalities do not follow up on complaints. Even where a municipality has an enforcement office, it may only be willing to issue warnings, since taking offenders to court is expensive.}

^{Many conflicts over noise pollution are handled by negotiation between the emitter and the receiver. Escalation procedures vary by country, and may include action in conjunction with local authorities, in particular the police. Noise pollution often persists because only five to ten percent of people affected by noise will lodge a formal complaint. Many people are not aware of their legal right to quiet and do not know how to register a complaint.}

Land pollution is often a consequence of increasing urbanization and industrialization. Man’s increasing demands on the environment and the resources it holds are putting countries under pressure.

The advent of the Industrial Revolution saw the beginning of this pressure and, although the emphasis may have changed, it still continues.

The Industrial Revolution set in motion a series of events which all impinged on the countryside destroying habitats. In no particular order, there were ;

[edit] Increased mechanization

In some areas more metal ores had to be extracted out of the ground, melted and cast using coal out of the ground and cooled using water, which raised the temperature of water in rivers. (This reduces the oxygen carrying capacity of the water and affects all the living things there.) The excavation of metal ores, sand and limestone led to large scale quarrying and defacing of the countryside. To a large extent this has stopped or is more closely controlled, and attempts have been made to use the holes profitably i.e. sand pits have been turned into boating lochs and quarries have been used as landfill waste sites. Central Scotland bears the scars of years of coal mining, with pit bings and slag heaps visible from the motorways.

[edit] Increased urbanization

As the demand for labor grew, the areas round the factories and mines were given over to housing. This took up former agricultural land, caused sewage and waste problems, increased the demands for food and put pressure on farmers to produce more food.

The demand for more housing meant the need to use more raw materials to make bricks, slates for roofing and timber for joists, etc. Once again this led to quarrying and to the destruction of forests. The houses also needed running water and a supply of energy. Initially this water would have been supplied directly from a stream but as demand increased the need for reservoirs increased. This again led to the loss of land as valleys were flooded to meet the demands. The main fuels used would have been coal and wood but as time progressed, hydro electric, coal, oil and nuclear power stations were built which again became features or eyesores on the landscape. Associated with this was the radiating network of pylons forming the National Grid, as well as, the sub stations and transformers. Until the late 1970s little attempt was made to hide these metal structures but now more care is taken in their siting and underground cables are often used – although these are not popular with repair crews who have to find faults and service them, often in very remote areas.

This increase in the concentration of population into cities, along with the internal combustion engine, led to the increased number of roads and all the infra structure that goes with them. Roads cause visual, noise, light, air and water pollution, as well as using up land. The visual and noise areas are obvious, however light pollution is becoming more widely recognised as a problem. From space large cities can be picked out at night by the glow of their street lighting, so city dwellers seldom experience total darkness. On a smaller scale lights along roads can cause people living there to have interrupted sleep patterns due to the lack of darkness.

The contribution of traffic to air pollution is dealt with in another article, but, suffice to say that sulfur dioxide, nitrogen oxides and carbon monoxide are the main culprits. Water pollution is caused by the run off from roads of oil, salt and rubber residue, which enter the water courses and may make conditions unsuitable for certain organisms to live.

[edit] Land Pollution

[edit] Increased agricultural land and field size

As the demand for food has grown so high has field size and mechanization. The increase in field size is to make it economically viable for the farmer but results in loss of habitat and shelter for wildlife as hedgerows and copses disappear. When crops are harvested the naked soil is left open to wind blow after the heavy machinery has crossed and compacted it. Another consequence of more intensive agriculture is the move to monoculture. This is unnatural, it depletes the soil of nutrients, allows diseases and pests to spread and, in short, brings into play the use of chemical substances foreign to the environment.

These foreign chemicals fall into four major groups – pesticides, herbicides, fungicides and insecticides.

[edit] Pesticides

Pesticides are any chemical used to remove pests whether they are plants or animals. They are used to kill wire worms and slugs that attack cereal crops and to kill ergot – Claviceps purpurea – a fungus that attacks crops and may get into human food.

[edit] Herbicides

Herbicides are used to kill weeds, especially on pavements and railways. They are similar to auxins and most are biodegradable by soil bacteria. However one group derived from trinitrophenol (2:4 D and 2:4:5 T) have the impurity dioxin which is very toxic and causes fatality even in low concentrations. It also causes spontaneous abortions, haemorraging and cancer. Agent Orange (50% 2:4:5 T) was used as a defoliant in Vietnam. Eleven million gallons were used and children born since then to American soldiers who served in this conflict, have shown increased physical and mental disabilities compared to the rest of the population. It affects the head of the sperm and the chromosomes inside it.

Another herbicide, much loved by murder story writers, is Paraquat. It is highly toxic but it rapidly degrades in soil due to the action of bacteria and does not kill soil fauna.

[edit] Fungicides

Fungicides are the group used to stop the growth of smuts and rusts on cereals, and mildews and molds like Mucor on plants. The problem is that they may contain copper and mercury. Copper is very toxic at 1ppm to water plants and fish and can enter the skin if being sprayed to reduce mildew and accumulate in the central nervous system. Organomercury compounds have been used to get rid of sedges which are insidious and difficult to remove. However it also can accumulate in birds’ central nervous system and kill them.

[edit] Insecticides

Insecticides are used to rid farmers of pests which damage crops. The insects damage not only standing crops but also stored ones and in the tropics it is reckoned that one third of the total production is lost during food storage. As with fungicides, the first used in the nineteenth century were inorganic e.g. Paris Green and other compounds of arsenic. Nicotine has also been used since the late eigtheenth century. There are now two main groups of synthetic ones -

Organochlorines

Organochlorines include DDT, Aldrin, Dieldrin and BHC. They are cheap to produce, potent and persistent. DDT was used on a massive scale from the 1930s, with a peak of 72,000 tonnes used 1970. Then usage fell as the environmental problems were realized. It was found worldwide in fish and birds and was even discovered in the snow in the Antarctic. It is only slightly soluble in water but is very soluble in the bloodstream. It affects the nervous and enzyme systems and causes the eggshells of birds to lack calcium and be so fragile that they break easily. It is thought to be responsible for the decline of the numbers of birds of prey like ospreys and peregrine falcons in the 1950s – they are now recovering.

As well as increased concentration via the food chain, it is known to enter via permeable membranes, so fish get it through their gills. As it has low solubility it tends to stay at the surface, so organisms that live there are most affected. DDT found in fish that formed part of the human food chain caused concern but the levels found in the liver, kidney and brain tissues was less than 1ppm and in fat was 10 ppm which was below the level likely to cause harm. However DDT was banned in Britain and America to stop the further building up of it in the food chain. However, the USA exploited this ban and sold DDT to developing countries who could not afford the expensive replacement chemicals and who did not have such stringent regulations governing the use of pesticides.

Some insects have developed a resistance to insecticides – e.g. the Anopheles mosquito which carries malaria.

Organophosphates

Organophosphates, e.g. parathion, methyl parathion and about 40 other insecticides are available nationally. Parathion is highly toxic, methyl-parathion is less so and Malathion is generally considered safe as it has low toxicity and is rapidly broken down in the mammalian liver. This group works by preventing normal nerve transmission as cholinesterase is prevented from breaking down the transmitter substance acetylcholine, resulting in uncontrolled muscle movements.

Entry of a variety of pesticides into our water supplies causes concern to environmental groups, as in many cases the long term effects of these specific chemicals is not known.

Limits came into force in July 1985 and were so frequently broken that in 1987 formal proceedings were taken against the British government. Britain is still the only European state to use Aldrin and organochlorines, although it was supposed to stop in 1993. East Anglia has the worst record for pesticide contamination of drinking water. Of the 350 pesticides used in Britain, only 50 can be analyzed – this is a worrying thought for many people.

[edit] Increased waste disposal

In Scotland in 1993, 14 million tons of waste were produced. 100,000 tons were special waste and 260,000 tons were controlled waste from other parts of Britain and abroad. 45% of the special waste were in liquid form and 18% were asbestos – radioactive waste was not included. Of the controlled waste, 48% comes from the demolition of buildings, 22% from industry, 17% from households and 13% from business – only 3% are recycled. 90% of controlled waste are buried in landfill sites and produces 2 million tons of methane gas. 1.5% is burned in incinerators and 1.5% are exported to be disposed of or recycled. There are 748 disposal sites in Scotland.

Landfill produces leachate, which has to be recycled to keep favorable conditions for microbial activity, and methane gas and carbon dioxide.

There are very little contaminated vacant or derelict land in the north east of Scotland as there are little traditional heavy industry or coal/mineral extraction. However some soil are contaminated by aromatic hydrocarbons (500 cubic meters).

The Urban Waste Water Treatment Directive allows sewage sludge to be sprayed onto land and the volume is expected to double to 185,000 tons of dry solids in 2005. This has good agricultural properties due to the high nitrogen and phosphate content. In 1990/1991, 13% wet weight was sprayed onto 0.13% of the land , however this is expected to rise 15 folds by 2005. There is a need to control this so that pathogenic microorganisms do not get into water courses and to ensure that there are no accumulation of heavy metals in the top soil.

[edit] Increased leisure and available wealth

As the twentieth century draws to a close, people have even more leisure time and available wealth. This means that people can travel around the countryside more in the increased number of cars. This is related back to the roads issue but has also led to the increased litter problem in the countryside. This is usually packaging, cans, bottles, etc. from picnics but increasingly people are dumping household rubbish in the countryside instead of taking it to the local tip. Aesthetically litter is unpleasant but poses threats to the wildlife through razor sharp glass that can be trodden on, plastic bags that can be eaten, etc. More and more litter is becoming a problem especially in the more remote areas which are now more accessible to the general public. Until the public take responsibility to stop littering, then legislation will have little effect and information and education will be the fore runners in the fight against the litter bugs.

[edit] Increased military presence

As nations grow so do their armed forces. Over the century, the army, the navy and latterly the air force has grown in Britain and so has their ownership of land. Apart from the noise and aviation fuel pollution of the air bases, the destruction of land on firing ranges and the change in coastlines to form naval bases, a more sinister trend is the increase in research stations with their “hidden agendas and experiments”. This was illustrated by a 1942 experiment on Gruinard Island off the west coast of Scotland.

Anthrax is caused by the bacterium Bacillus anthracis. It was discovered in the 1870s by the German scientist Robert Koch. It mainly affects herbivores, causing them to stagger, convulse and die in a few days. It can also affect man if the spores get onto the skin or lungs. It will form a pus filled blister and was initially treated by a vaccine prepared by Louis Pasteur in 1881. When an animal has died of the disease, the only safe way to dispose of it is to burn it or to bury it very deep in the earth.

However in World War II, knowing all the above problems, the British Government decided to use Anthrax as a biological weapon. In 1942 they dropped Anthrax bombs on Gruinard Island. Their idea – and indeed they produced these – was to drop 5 million Anthrax inoculated linseed cakes into fields of German cattle. The cattle cakes were destroyed at the end of the war unused. However, the Anthrax spores on Gruinard persisted for 40 years until in 1986 the whole island was decontaminated by formaldehyde, and in 1990 returned to its original owners.

This was an example of short sightedness that cost the island of Gruinard 50 years of its “natural life” and which could have spread out of control had it been used on mainland Europe.

Land pollution is often a consequence of increasing urbanization and industrialization. Man?s increasing demands on the environment and the resources it holds are putting countries under pressure.

The advent of the Industrial Revolution saw the beginning of this pressure and, although the emphasis may have changed, it still continues.

The Industrial Revolution set in motion a series of events which all impinged on the countryside destroying habitats. In no particular order, there were?;

[edit] Increased mechanization

In some areas more metal ores had to be extracted out of the ground, melted and cast using coal out of the ground and cooled using water, which raised the temperature of water in rivers. (This reduces the oxygen carrying capacity of the water and affects all the living things there.) The excavation of metal ores, sand and limestone led to large scale quarrying and defacing of the countryside. To a large extent this has stopped or is more closely controlled, and attempts have been made to use the holes profitably i.e. sand pits have been turned into boating lochs and quarries have been used as landfill waste sites. Central Scotland bears the scars of years of coal mining, with pit bings and slag heaps visible from the motorways.

[edit] Increased urbanization

As the demand for labor grew, the areas round the factories and mines were given over to housing. This took up former agricultural land, caused sewage and waste problems, increased the demands for food and put pressure on farmers to produce more food.

The demand for more housing meant the need to use more raw materials to make bricks, slates for roofing and timber for joists, etc. Once again this led to quarrying and to the destruction of forests. The houses also needed running water and a supply of energy. Initially this water would have been supplied directly from a stream but as demand increased the need for reservoirs increased. This again led to the loss of land as valleys were flooded to meet the demands. The main fuels used would have been coal and wood but as time progressed, hydro electric, coal, oil and nuclear power stations were built which again became features or eyesores on the landscape. Associated with this was the radiating network of pylons forming the National Grid, as well as, the sub stations and transformers. Until the late 1970s little attempt was made to hide these metal structures but now more care is taken in their siting and underground cables are often used – although these are not popular with repair crews who have to find faults and service them, often in very remote areas.

This increase in the concentration of population into cities, along with the internal combustion engine, led to the increased number of roads and all the infra structure that goes with them. Roads cause visual, noise, light, air and water pollution, as well as using up land. The visual and noise areas are obvious, however light pollution is becoming more widely recognised as a problem. From space large cities can be picked out at night by the glow of their street lighting, so city dwellers seldom experience total darkness. On a smaller scale lights along roads can cause people living there to have interrupted sleep patterns due to the lack of darkness.

The contribution of traffic to air pollution is dealt with in another article, but, suffice to say that sulfur dioxide, nitrogen oxides and carbon monoxide are the main culprits. Water pollution is caused by the run off from roads of oil, salt and rubber residue, which enter the water courses and may make conditions unsuitable for certain organisms to live.

[edit] Land Pollution

[edit] Increased agricultural land and field size

As the demand for food has grown so high has field size and mechanization. The increase in field size is to make it economically viable for the farmer but results in loss of habitat and shelter for wildlife as hedgerows and copses disappear. When crops are harvested the naked soil is left open to wind blow after the heavy machinery has crossed and compacted it. Another consequence of more intensive agriculture is the move to monoculture. This is unnatural, it depletes the soil of nutrients, allows diseases and pests to spread and, in short, brings into play the use of chemical substances foreign to the environment.

These foreign chemicals fall into four major groups – pesticides, herbicides, fungicides and insecticides.

[edit] Pesticides

Pesticides are any chemical used to remove pests whether they are plants or animals. They are used to kill wire worms and slugs that attack cereal crops and to kill ergot – Claviceps purpurea – a fungus that attacks crops and may get into human food.

[edit] Herbicides

Herbicides are used to kill weeds, especially on pavements and railways. They are similar to auxins and most are biodegradable by soil bacteria. However one group derived from trinitrophenol (2:4 D and 2:4:5 T) have the impurity dioxin which is very toxic and causes fatality even in low concentrations. It also causes spontaneous abortions, haemorraging and cancer. Agent Orange (50% 2:4:5 T) was used as a defoliant in Vietnam. Eleven million gallons were used and children born since then to American soldiers who served in this conflict, have shown increased physical and mental disabilities compared to the rest of the population. It affects the head of the sperm and the chromosomes inside it.

Another herbicide, much loved by murder story writers, is Paraquat. It is highly toxic but it rapidly degrades in soil due to the action of bacteria and does not kill soil fauna.

[edit] Fungicides

Fungicides are the group used to stop the growth of smuts and rusts on cereals, and mildews and molds like Mucor on plants. The problem is that they may contain copper and mercury. Copper is very toxic at 1ppm to water plants and fish and can enter the skin if being sprayed to reduce mildew and accumulate in the central nervous system. Organomercury compounds have been used to get rid of sedges which are insidious and difficult to remove. However it also can accumulate in birds? central nervous system and kill them.

[edit] Insecticides

Insecticides are used to rid farmers of pests which damage crops. The insects damage not only standing crops but also stored ones and in the tropics it is reckoned that one third of the total production is lost during food storage. As with fungicides, the first used in the nineteenth century were inorganic e.g. Paris Green and other compounds of arsenic. Nicotine has also been used since the late eigtheenth century. There are now two main groups of synthetic ones -

Organochlorines

Organochlorines include DDT, Aldrin, Dieldrin and BHC. They are cheap to produce, potent and persistent. DDT was used on a massive scale from the 1930s, with a peak of 72,000 tonnes used 1970. Then usage fell as the environmental problems were realized. It was found worldwide in fish and birds and was even discovered in the snow in the Antarctic. It is only slightly soluble in water but is very soluble in the bloodstream. It affects the nervous and enzyme systems and causes the eggshells of birds to lack calcium and be so fragile that they break easily. It is thought to be responsible for the decline of the numbers of birds of prey like ospreys and peregrine falcons in the 1950s – they are now recovering.

As well as increased concentration via the food chain, it is known to enter via permeable membranes, so fish get it through their gills. As it has low solubility it tends to stay at the surface, so organisms that live there are most affected. DDT found in fish that formed part of the human food chain caused concern but the levels found in the liver, kidney and brain tissues was less than 1ppm and in fat was 10 ppm which was below the level likely to cause harm. However DDT was banned in Britain and America to stop the further building up of it in the food chain. However, the USA exploited this ban and sold DDT to developing countries who could not afford the expensive replacement chemicals and who did not have such stringent regulations governing the use of pesticides.

Some insects have developed a resistance to insecticides – e.g. the Anopheles mosquito which carries malaria.

Organophosphates

Organophosphates, e.g. parathion, methyl parathion and about 40 other insecticides are available nationally. Parathion is highly toxic, methyl-parathion is less so and Malathion is generally considered safe as it has low toxicity and is rapidly broken down in the mammalian liver. This group works by preventing normal nerve transmission as cholinesterase is prevented from breaking down the transmitter substance acetylcholine, resulting in uncontrolled muscle movements.

Entry of a variety of pesticides into our water supplies causes concern to environmental groups, as in many cases the long term effects of these specific chemicals is not known.

Limits came into force in July 1985 and were so frequently broken that in 1987 formal proceedings were taken against the British government. Britain is still the only European state to use Aldrin and organochlorines, although it was supposed to stop in 1993. East Anglia has the worst record for pesticide contamination of drinking water. Of the 350 pesticides used in Britain, only 50 can be analyzed – this is a worrying thought for many people.

[edit] Increased waste disposal

In Scotland in 1993, 14 million tons of waste were produced. 100,000 tons were special waste and 260,000 tons were controlled waste from other parts of Britain and abroad. 45% of the special waste were in liquid form and 18% were asbestos – radioactive waste was not included. Of the controlled waste, 48% comes from the demolition of buildings, 22% from industry, 17% from households and 13% from business – only 3% are recycled. 90% of controlled waste are buried in landfill sites and produces 2 million tons of methane gas. 1.5% is burned in incinerators and 1.5% are exported to be disposed of or recycled. There are 748 disposal sites in Scotland.

Landfill produces leachate, which has to be recycled to keep favorable conditions for microbial activity, and methane gas and carbon dioxide.

There are very little contaminated vacant or derelict land in the north east of Scotland as there are little traditional heavy industry or coal/mineral extraction. However some soil are contaminated by aromatic hydrocarbons (500 cubic meters).

The Urban Waste Water Treatment Directive allows sewage sludge to be sprayed onto land and the volume is expected to double to 185,000 tons of dry solids in 2005. This has good agricultural properties due to the high nitrogen and phosphate content. In 1990/1991, 13% wet weight was sprayed onto 0.13% of the land , however this is expected to rise 15 folds by 2005. There is a need to control this so that pathogenic microorganisms do not get into water courses and to ensure that there are no accumulation of heavy metals in the top soil.

[edit] Increased leisure and available wealth

As the twentieth century draws to a close, people have even more leisure time and available wealth. This means that people can travel around the countryside more in the increased number of cars. This is related back to the roads issue but has also led to the increased litter problem in the countryside. This is usually packaging, cans, bottles, etc. from picnics but increasingly people are dumping household rubbish in the countryside instead of taking it to the local tip. Aesthetically litter is unpleasant but poses threats to the wildlife through razor sharp glass that can be trodden on, plastic bags that can be eaten, etc. More and more litter is becoming a problem especially in the more remote areas which are now more accessible to the general public. Until the public take responsibility to stop littering, then legislation will have little effect and information and education will be the fore runners in the fight against the litter bugs.

[edit] Increased military presence

As nations grow so do their armed forces. Over the century, the army, the navy and latterly the air force has grown in Britain and so has their ownership of land. Apart from the noise and aviation fuel pollution of the air bases, the destruction of land on firing ranges and the change in coastlines to form naval bases, a more sinister trend is the increase in research stations with their “hidden agendas and experiments”. This was illustrated by a 1942 experiment on Gruinard Island off the west coast of Scotland.

Anthrax is caused by the bacterium Bacillus anthracis. It was discovered in the 1870s by the German scientist Robert Koch. It mainly affects herbivores, causing them to stagger, convulse and die in a few days. It can also affect man if the spores get onto the skin or lungs. It will form a pus filled blister and was initially treated by a vaccine prepared by Louis Pasteur in 1881. When an animal has died of the disease, the only safe way to dispose of it is to burn it or to bury it very deep in the earth.

However in World War II, knowing all the above problems, the British Government decided to use Anthrax as a biological weapon. In 1942 they dropped Anthrax bombs on Gruinard Island. Their idea – and indeed they produced these – was to drop 5 million Anthrax inoculated linseed cakes into fields of German cattle. The cattle cakes were destroyed at the end of the war unused. However, the Anthrax spores on Gruinard persisted for 40 years until in 1986 the whole island was decontaminated by formaldehyde, and in 1990 returned to its original owners.

This was an example of short sightedness that cost the island of Gruinard 50 years of its “natural life” and which could have spread out of control had it been used on mainland Europe.

Although natural phenomena such as volcanoes, algae blooms, storms, and earthquakes also cause major changes in water quality and the ecological status of water, these are not deemed to be pollution. Water is only called polluted when it is not able to be used for what one wants it to be used for. Water pollution has many causes and characteristics. Increases in nutrient loading may lead to eutrophication. Organic wastes such as sewage impose high oxygen demands on the receiving water leading to oxygen depletion with potentially severe impacts on the whole eco-system. Industries discharge a variety of pollutants in their wastewater including heavy metals, resin pellets, organic toxins, oils, nutrients, and solids. Discharges can also have thermal effects, especially those from power stations, and these too reduce the available oxygen. Silt-bearing runoff from many activities including construction sites, deforestation and agriculture can inhibit the penetration of sunlight through the water column, restricting photosynthesis and causing blanketing of the lake or river bed, in turn damaging ecological systems.

Pollutants in water include a wide spectrum of chemicals, pathogens, and physical chemistry or sensory changes. Many of the chemical substances are toxic. Pathogens can produce waterborne diseases in either human or animal hosts. Alteration of water’s physical chemistry include acidity, electrical conductivity, temperature, and eutrophication. Eutrophication is the fertilisation of surface water by nutrients that were previously scarce. Even many of the municipal water supplies in developed countries can present health risks. Water pollution is a major problem in the global context. It has been suggested that it is the leading worldwide cause of deaths and diseases,^[1][2] and that it accounts for the deaths of more than 14,000 people daily.^[2]

[edit] Sources of water pollution

Some of the principal sources of water pollution are:

• Geology of aquifers from which groundwater is abstracted
• Industrial discharge of chemical wastes and byproducts
• Discharge of poorly-treated or untreated sewage
• Surface runoff containing pesticides or fertilizers
• Slash and burn farming practice, which is often an element within shifting cultivation agricultural systems
• Surface runoff containing spilled petroleum products
• Surface runoff from construction sites, farms, or paved and other impervious surfaces e.g. silt
• Discharge of contaminated and/or heated water used for industrial processes
• Acid rain caused by industrial discharge of sulphur dioxide (by burning high-sulphur fossil fuels)
• Excess nutrients are added (eutrophication) by runoff containing detergents or fertilizers
• Underground storage tank leakage, leading to soil contamination, and hence aquifer contamination
• Inappropriate disposal of various solid wastes and, on a localized scale, littering
• Oil spills

Accumulation of litter and organic debris in Salford Quays, a section of the Manchester Ship Canal in Greater Manchester, UK.

[edit] Contaminants

Contaminants may include organic and inorganic substances.

Some organic water pollutants are:

• Insecticides and herbicides, a huge range of organohalide and other chemicals
• Bacteria, often is from sewage or livestock operations
• Food processing waste, including pathogens
• Tree and brush debris from logging operations
• VOCs (Volatile organic compounds), such as industrial solvents, from improper storage
• Petroleum Hydrocarbons including fuels (gasoline, diesel, jet fuels, and fuel oils) and lubricants (motor oil) from oil field operations, refineries, pipelines, retail service station’s underground storage tanks, and transfer operations. Note: VOCs include gasoline-range hydrocarbons.

Some inorganic water pollutants include:

• Heavy metals including acid mine drainage
• Acidity caused by industrial discharges (especially sulfur dioxide from power plants)
• Pre-production industrial raw resin pellets, an industrial pollutant
• Chemical waste as industrial by products
• Fertilizers, in runoff from agriculture including nitrates and phosphates
• Silt in surface runoff from construction sites, logging, slash and burn practices or land clearing sites

[edit] Transport and chemical reactions of water pollutants

Most water pollutants are eventually carried by the rivers into the oceans. In some areas of the world the influence can be traced hundred miles from the mouth by studies using hydrology transport models. Advanced computer models such as SWMM or the DSSAM Model have been used in many locations worldwide to examine the fate of pollutants in aquatic systems. Indicator filter feeding species such as copepods have also been used to study pollutant fates in the New York Bight, for example. The highest toxin loads are not directly at the mouth of the Hudson River, but 100 kilometers south, since several days are required for incorporation into planktonic tissue. The Hudson discharge flows south along the coast due to coriolis force. Further south then are areas of oxygen depletion, caused by chemicals using up oxygen and by algae blooms, caused by excess nutrients from algal cell death and decomposition. Fish and shellfish kills have been reported, because toxins climb the foodchain after small fish consume copepods, then large fish eat smaller fish, etc. Each successive step up the food chain causes a stepwise concentration of pollutants such as heavy metals (e.g. mercury) and persistent organic pollutants such as DDT. This is known as biomagnification which is occasionally used interchangeably with bioaccumulation.

The big gyres in the oceans trap floating plastic debris. The North Pacific Gyre for example has collected the so-called Great Pacific Garbage Patch that is now estimated at two times the size of Texas. Many of these long-lasting pieces wind up in the stomachs of marine birds and animals. This results in obstruction of digestive pathways which leads to reduced appetite or even starvation.

Many chemicals undergo reactive decay or chemically change especially over long periods of time in groundwater reservoirs. A noteworthy class of such chemicals are the chlorinated hydrocarbons such as trichloroethylene (used in industrial metal degreasing and electronics manufacturing) and tetrachloroethylene used in the dry cleaning industry (note latest advances in liquid carbon dioxide in dry cleaning that avoids all use of chemicals). Both of these chemicals, which are carcinogens themselves, undergo partial decomposition reactions, leading to new hazardous chemicals (including dichloroethylene and vinyl chloride).

Groundwater pollution is much more difficult to abate than surface pollution because groundwater can move great distances through unseen aquifers. Non-porous aquifers such as clays partially purify water of bacteria by simple filtration (adsorption and absorption), dilution, and, in some cases, chemical reactions and biological activity: however, in some cases, the pollutants merely transform to soil contaminants. Groundwater that moves through cracks and caverns is not filtered and can be transported as easily as surface water. In fact, this can be aggravated by the human tendency to use natural sinkholes as dumps in areas of Karst topography.

There are a variety of secondary effects stemming not from the original pollutant, but a derivative condition. Some of these secondary impacts are:

• Silt bearing surface runoff from can inhibit the penetration of sunlight through the water column, hampering photosynthesis in aquatic plants.
• Thermal pollution can induce fish kills and invasion by new thermophyllic species

[edit] Regulatory framework

In the UK there are common law rights (civil rights) to protect the passage of water across land unfettered in either quality of quantity. Criminal laws dating back to the 16th century exercised some control over water pollution but it was not until the River (Prevention of pollution )Acts 1951 – 1961 were enacted that any systematic control over water pollution was established. These laws were strengthened and extended in the Control of Pollution Act 1984 which has since been updated and modified by a series of further acts. It is a criminal offense to either pollute a lake, river, groundwater or the sea or to discharge any liquid into such water bodies without proper authority. In England and Wales such permission can only be issued by the Environment Agency and in Scotland by SEPA.

In the USA, concern over water pollution resulted in the enactment of state anti-pollution laws in the latter half of the 19th century, and federal legislation enacted in 1899. The Refuse Act of the federal Rivers and Harbors Act of 1899 prohibits the disposal of any refuse matter from into either the nation’s navigable rivers, lakes, streams, and other navigable bodies of water, or any tributary to such waters, unless one has first obtained a permit. The Water Pollution Control Act, passed in 1948, gave authority to the Surgeon General to reduce water pollution.

Growing public awareness and concern for controlling water pollution led to enactment of the Federal Water Pollution Control Act Amendments of 1972. As amended in 1977, this law became commonly known as the Clean Water Act. The Act established the basic mechanisms for regulating contaminant discharge. It established the authority for the United States Environmental Protection Agency to implement wastewater standards for industry. The Clean Water Act also continued requirements to set water quality standards for all contaminants in surface waters. Further amplification of the Act continued including the enactment of the Great Lakes Legacy Act of 2002.^[3]

Land pollution is often a consequence of increasing urbanization and industrialization. Man’s increasing demands on the environment and the resources it holds are putting countries under pressure.

The advent of the Industrial Revolution saw the beginning of this pressure and, although the emphasis may have changed, it still continues.

The Industrial Revolution set in motion a series of events which all impinged on the countryside destroying habitats. In no particular order, there were ;

[edit] Land Pollution

[edit] Increased agricultural land and field size

As the demand for food has grown so high has field size and mechanization. The increase in field size is to make it economically viable for the farmer but results in loss of habitat and shelter for wildlife as hedgerows and copses disappear. When crops are harvested the naked soil is left open to wind blow after the heavy machinery has crossed and compacted it. Another consequence of more intensive agriculture is the move to monoculture. This is unnatural, it depletes the soil of nutrients, allows diseases and pests to spread and, in short, brings into play the use of chemical substances foreign to the environment.

These foreign chemicals fall into four major groups – pesticides, herbicides, fungicides and insecticides.

[edit] Pesticides

Pesticides are any chemical used to remove pests whether they are plants or animals. They are used to kill wire worms and slugs that attack cereal crops and to kill ergot – Claviceps purpurea – a fungus that attacks crops and may get into human food.

[edit] Herbicides

Herbicides are used to kill weeds, especially on pavements and railways. They are similar to auxins and most are biodegradable by soil bacteria. However one group derived from trinitrophenol (2:4 D and 2:4:5 T) have the impurity dioxin which is very toxic and causes fatality even in low concentrations. It also causes spontaneous abortions, haemorraging and cancer. Agent Orange (50% 2:4:5 T) was used as a defoliant in Vietnam. Eleven million gallons were used and children born since then to American soldiers who served in this conflict, have shown increased physical and mental disabilities compared to the rest of the population. It affects the head of the sperm and the chromosomes inside it.

Another herbicide, much loved by murder story writers, is Paraquat. It is highly toxic but it rapidly degrades in soil due to the action of bacteria and does not kill soil fauna.

[edit] Fungicides

Fungicides are the group used to stop the growth of smuts and rusts on cereals, and mildews and molds like Mucor on plants. The problem is that they may contain copper and mercury. Copper is very toxic at 1ppm to water plants and fish and can enter the skin if being sprayed to reduce mildew and accumulate in the central nervous system. Organomercury compounds have been used to get rid of sedges which are insidious and difficult to remove. However it also can accumulate in birds’ central nervous system and kill them.

[edit] Insecticides

Insecticides are used to rid farmers of pests which damage crops. The insects damage not only standing crops but also stored ones and in the tropics it is reckoned that one third of the total production is lost during food storage. As with fungicides, the first used in the nineteenth century were inorganic e.g. Paris Green and other compounds of arsenic. Nicotine has also been used since the late eigtheenth century. There are now two main groups of synthetic ones -

Organochlorines

Organochlorines include DDT, Aldrin, Dieldrin and BHC. They are cheap to produce, potent and persistent. DDT was used on a massive scale from the 1930s, with a peak of 72,000 tonnes used 1970. Then usage fell as the environmental problems were realized. It was found worldwide in fish and birds and was even discovered in the snow in the Antarctic. It is only slightly soluble in water but is very soluble in the bloodstream. It affects the nervous and enzyme systems and causes the eggshells of birds to lack calcium and be so fragile that they break easily. It is thought to be responsible for the decline of the numbers of birds of prey like ospreys and peregrine falcons in the 1950s – they are now recovering.

As well as increased concentration via the food chain, it is known to enter via permeable membranes, so fish get it through their gills. As it has low solubility it tends to stay at the surface, so organisms that live there are most affected. DDT found in fish that formed part of the human food chain caused concern but the levels found in the liver, kidney and brain tissues was less than 1ppm and in fat was 10 ppm which was below the level likely to cause harm. However DDT was banned in Britain and America to stop the further building up of it in the food chain. However, the USA exploited this ban and sold DDT to developing countries who could not afford the expensive replacement chemicals and who did not have such stringent regulations governing the use of pesticides.

Some insects have developed a resistance to insecticides – e.g. the Anopheles mosquito which carries malaria.

Organophosphates

Organophosphates, e.g. parathion, methyl parathion and about 40 other insecticides are available nationally. Parathion is highly toxic, methyl-parathion is less so and Malathion is generally considered safe as it has low toxicity and is rapidly broken down in the mammalian liver. This group works by preventing normal nerve transmission as cholinesterase is prevented from breaking down the transmitter substance acetylcholine, resulting in uncontrolled muscle movements.

Entry of a variety of pesticides into our water supplies causes concern to environmental groups, as in many cases the long term effects of these specific chemicals is not known.

Limits came into force in July 1985 and were so frequently broken that in 1987 formal proceedings were taken against the British government. Britain is still the only European state to use Aldrin and organochlorines, although it was supposed to stop in 1993. East Anglia has the worst record for pesticide contamination of drinking water. Of the 350 pesticides used in Britain, only 50 can be analyzed – this is a worrying thought for many people.

[edit] Increased waste disposal

In Scotland in 1993, 14 million tons of waste were produced. 100,000 tons were special waste and 260,000 tons were controlled waste from other parts of Britain and abroad. 45% of the special waste were in liquid form and 18% were asbestos – radioactive waste was not included. Of the controlled waste, 48% comes from the demolition of buildings, 22% from industry, 17% from households and 13% from business – only 3% are recycled. 90% of controlled waste are buried in landfill sites and produces 2 million tons of methane gas. 1.5% is burned in incinerators and 1.5% are exported to be disposed of or recycled. There are 748 disposal sites in Scotland.

Landfill produces leachate, which has to be recycled to keep favorable conditions for microbial activity, and methane gas and carbon dioxide.

There are very little contaminated vacant or derelict land in the north east of Scotland as there are little traditional heavy industry or coal/mineral extraction. However some soil are contaminated by aromatic hydrocarbons (500 cubic meters).

The Urban Waste Water Treatment Directive allows sewage sludge to be sprayed onto land and the volume is expected to double to 185,000 tons of dry solids in 2005. This has good agricultural properties due to the high nitrogen and phosphate content. In 1990/1991, 13% wet weight was sprayed onto 0.13% of the land , however this is expected to rise 15 folds by 2005. There is a need to control this so that pathogenic microorganisms do not get into water courses and to ensure that there are no accumulation of heavy metals in the top soil.

[edit] Increased leisure and available wealth

As the twentieth century draws to a close, people have even more leisure time and available wealth. This means that people can travel around the countryside more in the increased number of cars. This is related back to the roads issue but has also led to the increased litter problem in the countryside. This is usually packaging, cans, bottles, etc. from picnics but increasingly people are dumping household rubbish in the countryside instead of taking it to the local tip. Aesthetically litter is unpleasant but poses threats to the wildlife through razor sharp glass that can be trodden on, plastic bags that can be eaten, etc. More and more litter is becoming a problem especially in the more remote areas which are now more accessible to the general public. Until the public take responsibility to stop littering, then legislation will have little effect and information and education will be the fore runners in the fight against the litter bugs.

[edit] Increased military presence

As nations grow so do their armed forces. Over the century, the army, the navy and latterly the air force has grown in Britain and so has their ownership of land. Apart from the noise and aviation fuel pollution of the air bases, the destruction of land on firing ranges and the change in coastlines to form naval bases, a more sinister trend is the increase in research stations with their “hidden agendas and experiments”. This was illustrated by a 1942 experiment on Gruinard Island off the west coast of Scotland.

Anthrax is caused by the bacterium Bacillus anthracis. It was discovered in the 1870s by the German scientist Robert Koch. It mainly affects herbivores, causing them to stagger, convulse and die in a few days. It can also affect man if the spores get onto the skin or lungs. It will form a pus filled blister and was initially treated by a vaccine prepared by Louis Pasteur in 1881. When an animal has died of the disease, the only safe way to dispose of it is to burn it or to bury it very deep in the earth.

However in World War II, knowing all the above problems, the British Government decided to use Anthrax as a biological weapon. In 1942 they dropped Anthrax bombs on Gruinard Island. Their idea – and indeed they produced these – was to drop 5 million Anthrax inoculated linseed cakes into fields of German cattle. The cattle cakes were destroyed at the end of the war unused. However, the Anthrax spores on Gruinard persisted for 40 years until in 1986 the whole island was decontaminated by formaldehyde, and in 1990 returned to its original owners.

This was an example of short sightedness that cost the island of Gruinard 50 years of its “natural life” and which could have spread out of control had it been used on mainland Europe.

Air Pollution

Air pollution is the modification of the natural characteristics of the atmosphere by a chemical, particulate matter, or biological agent. The atmosphere is a complex, dynamic natural gaseous system that is essential to support life on planet Earth. Stratospheric ozone depletion due to air pollution has long been recognized as a threat to human health as well as to the Earth’s ecosystems.

Worldwide air pollution is responsible for large numbers of deaths and cases of respiratory disease. While major stationary sources are often identified with air pollution, the greatest source of emissions is actually mobile sources, mainly automobiles. Gases such as carbon dioxide, which contribute to global warming, have recently gained recognition as pollutants by some scientists.