Water pollution pdf file

Date published 

 

water pollution is and equally to address the source, effect control and water to be the presence of excessive amounts of a hazard (pollutants) in water in such. PDF | On Jan 1, , Asha Gupta and others published WATER POLLUTION- SOURCES,EFFECTS AND CONTROL. PDF | At global level, three fourth of the earth's surface is covered with water resources comprising % salt water and the balance % as.

Author:DORATHY LEGARRETA
Language:English, Spanish, Portuguese
Country:Switzerland
Genre:Lifestyle
Pages:672
Published (Last):06.10.2015
ISBN:597-1-40334-911-4
Distribution:Free* [*Registration needed]
Uploaded by: KRISTOFER

63218 downloads 85920 Views 19.31MB PDF Size Report


Water Pollution Pdf File

Introduction: Water is a basic natural resource required by all human beings. Man requires a minimum body intake of water that varies from - 13 litres per. Students explore the subject of water pollution by working in 6. http://focus. mtn-i.info Information about the types, causes, and effects of water pollution and what we can do to solve the problem.

Last updated: March 24, Over two thirds of Earth's surface is covered by water ; less than a third is taken up by land. As Earth's population continues to grow, people are putting ever-increasing pressure on the planet's water resources. In a sense, our oceans, rivers , and other inland waters are being "squeezed" by human activities—not so they take up less room, but so their quality is reduced. Poorer water quality means water pollution. We know that pollution is a human problem because it is a relatively recent development in the planet's history: before the 19th century Industrial Revolution, people lived more in harmony with their immediate environment. As industrialization has spread around the globe, so the problem of pollution has spread with it. When Earth's population was much smaller, no one believed pollution would ever present a serious problem. It was once popularly believed that the oceans were far too big to pollute. Today, with around 7 billion people on the planet, it has become apparent that there are limits. Pollution is one of the signs that humans have exceeded those limits. How serious is the problem? According to the environmental campaign organization WWF: "Pollution from toxic chemicals threatens life on this planet.

Ideally, statistics should be based on ten years of observation. If only shorter time series are available, it should be ascertained that they are representative for a longer period.

This can be done, for example, by analysis of longer time series from other observations sites. The meteorological time series used also has to be representative of the site considered - that is, it must reflect the local characteristics. This is specially important concerning air quality standards based on peak fractions of the distribution, like 98 percentiles. If no such time series is at hand, a meteorological flow model may be used to calculate one from other data, as will be described below.

Concepts of Air Pollution Modelling As mentioned above, dispersion of pollutants is dependent on emission conditions, transport and turbulent mixing. Using the full equation which describes these features is called Eulerian dispersion modelling Pielke By this approach, gains and losses of the pollutant in question have to be determined at every point on an imaginary spatial grid and in distinct time steps. As this method is very complex and computer time consuming, it usually cannot be handled routinely.

In this case, the equation mentioned above can be solved analytically. The resulting formula describes a plume with Gaussian concentration distribution, the so called Gaussian plume model VDI The distribution parameters depend on meteorological conditions and downwind distance as well as on stack height.

They have to be determined empirically Venkatram and Wyngaard Under this approach, distinct puffs are emitted in fixed time steps, each following its own path according to the current meteorological conditions.

On its way, each puff grows according to turbulent mixing. Parameters describing this growth, again, have to be determined from empirical data Venkatram and Wyngaard Concerning accidental releases or single case studies, a Lagrangian or particle model VDI Guideline , Part 3 is recommended. The concept thereby is to calculate the paths of many particles, each of which represents a fixed amount of the pollutant in question. The individual paths are composed of transport by the mean wind and of stochastic disturbances.

Due to the stochastic part, the paths do not fully agree, but depict the mixture by turbulence. In principle, Lagrangian models are capable of considering complex meteorological conditions - in particular, wind and turbulence; fields calculated by flow models described below can be used for Lagrangian dispersion modelling.

Dispersion Modelling in Complex Terrain If pollutant concentrations have to be determined in structured terrain, it may be necessary to include topographic effects on pollutant dispersion in modelling. Such effects are, for example, transport following the topographic structure, or thermal wind systems like sea breezes or mountain winds, which change wind direction in the course of the day.

If such effects take place on a scale much larger than the model area, the influence may be considered by using meteorological data which reflect the local characteristics. If no such data are available, the three-dimensional structure impressed on the flow by topography can be obtained by using a corresponding flow model.

Based on these data, dispersion modelling itself may be carried out assuming horizontal homogeneity as described above in the case of the Gaussian plume model. However, in situations where wind conditions change significantly inside the model area, dispersion modelling itself has to consider the three-dimensional flow affected by the topographic structure.

As mentioned above, this may be done by using a Gaussian puff or a Lagrangian model. Another way is to perform the more complex Eulerian modelling. To determine wind direction in accord with the topographically structured terrain, mass consistent or diagnostic flow modelling may be used Pielke Using this approach, the flow is fitted to topography by varying the initial values as little as possible and by keeping its mass consistent.

As this is an approach which leads to quick results, it may also be used to calculate wind statistics for a certain site if no observations are available.

To do this, geostrophic wind statistics i. If, however, thermal wind systems have to be considered in more detail, so called prognostic models have to be used. Depending on the scale and the steepness of the model area, a hydrostatic, or the even more complex non-hydrostatic, approach is suitable VDI Models of this type need much computer power, as well as much experience in application.

Determination of concentrations based on annual means, in general, are not possible with these models. Instead, worst case studies can be performed by considering only one wind direction and those wind speed and stratification parameters which result in the highest surface concentration values.

If those worst case values do not exceed air quality standards, more detailed studies are not necessary. Road traffic emissions will be trapped to a certain amount in street canyons. Empirical formulations have been found to describe this Yamartino and Wiegand Pollutants emitted from a low stack situated on a building will be captured in the circulation on the lee side of the building.

The extent of this lee circulation depends on the height and width of the building, as well as on wind speed. Therefore, simplified approaches to describe pollutant dispersion in such a case, based solely on the height of a building, are not generally valid. The vertical and horizontal extent of the lee circulation has been obtained from wind tunnel studies Hosker and can be implemented in mass consistent diagnostic models.

As soon as the flow field has been determined, it can be used to calculate the transport and turbulent mixing of the pollutant emitted. This can be done by Lagrangian or Eulerian dispersion modelling. More detailed studies - concerning accidental releases, for instance - can be performed only by using non-hydrostatic flow and dispersion models instead of a diagnostic approach. As this, in general, demands high computer power, a worst case approach as described above is recommended in advance of a complete statistical modelling.

Ambient air pollutant concentrations are influenced by the spatial or time variance of emissions of hazardous substances and the dynamics of their dispersion in the air. As a consequence, marked daily and annual variations of concentrations occur. It is practically impossible to determine in a unified way all these different variations of air quality in statistical language, the population of air quality states.

Thus, ambient air pollutant concentrations measurements always have the character of random spatial or time samples. Measurement Planning The first step in measurement planning is to formulate the purpose of the measurement as precisely as possible.

Water pollution: an introduction

As industrialization has spread around the globe, so the problem of pollution has spread with it. When Earth's population was much smaller, no one believed pollution would ever present a serious problem. It was once popularly believed that the oceans were far too big to pollute. Today, with around 7 billion people on the planet, it has become apparent that there are limits. Pollution is one of the signs that humans have exceeded those limits. How serious is the problem? According to the environmental campaign organization WWF: "Pollution from toxic chemicals threatens life on this planet.

Every ocean and every continent, from the tropics to the once-pristine polar regions, is contaminated. What is water pollution? Water pollution can be defined in many ways. Usually, it means one or more substances have built up in water to such an extent that they cause problems for animals or people.

Oceans, lakes, rivers, and other inland waters can naturally clean up a certain amount of pollution by dispersing it harmlessly. If you poured a cup of black ink into a river, the ink would quickly disappear into the river's much larger volume of clean water. The ink would still be there in the river, but in such a low concentration that you would not be able to see it. At such low levels, the chemicals in the ink probably would not present any real problem.

However, if you poured gallons of ink into a river every few seconds through a pipe, the river would quickly turn black. The chemicals in the ink could very quickly have an effect on the quality of the water. This, in turn, could affect the health of all the plants, animals, and humans whose lives depend on the river.

Photo: Pollution means adding substances to the environment that don't belong there—like the air pollution from this smokestack. Pollution is not always as obvious as this, however. Thus, water pollution is all about quantities: how much of a polluting substance is released and how big a volume of water it is released into.

A small quantity of a toxic chemical may have little impact if it is spilled into the ocean from a ship. But the same amount of the same chemical can have a much bigger impact pumped into a lake or river, where there is less clean water to disperse it.

Water pollution almost always means that some damage has been done to an ocean, river, lake, or other water source. A United Nations report defined ocean pollution as: "The introduction by man, directly or indirectly, of substances or energy into the marine environment including estuaries resulting in such deleterious effects as harm to living resources, hazards to human health, hindrance to marine activities, including fishing, impairment of quality for use of sea water and reduction of amenities.

What are the main types of water pollution? When we think of Earth's water resources, we think of huge oceans, lakes, and rivers.

Water resources like these are called surface waters. The most obvious type of water pollution affects surface waters. For example, a spill from an oil tanker creates an oil slick that can affect a vast area of the ocean.

Not all of Earth's water sits on its surface, however. A great deal of water is held in underground rock structures known as aquifers, which we cannot see and seldom think about. Water stored underground in aquifers is known as groundwater. Aquifers feed our rivers and supply much of our drinking water. They too can become polluted, for example, when weed killers used in people's gardens drain into the ground.

Groundwater pollution is much less obvious than surface-water pollution, but is no less of a problem. In , a study in Iowa in the United States found that over half the state's groundwater wells were contaminated with weed killers. You might think things would have improved since then, but, two decades on, all that's really changed is the name of the chemicals we're using.

Today, numerous scientific studies are still finding weed killers in groundwater in worrying quantities: a study discovered glyphosate in 41 percent of groundwater samples from Catalonia, Spain; scientific opinion differs on whether this is safe or not.

There are also two different ways in which pollution can occur. If pollution comes from a single location, such as a discharge pipe attached to a factory, it is known as point-source pollution. Other examples of point source pollution include an oil spill from a tanker, a discharge from a smoke stack factory chimney , or someone pouring oil from their car down a drain.

Water Pollution Seminar Pdf Report with PPT

A great deal of water pollution happens not from one single source but from many different scattered sources. This is called nonpoint-source pollution. Photo: Above: Point-source pollution comes from a single, well-defined place such as this pipe. Below: Nonpoint-source pollution comes from many sources.

All the industrial plants alongside a river and the ships that service them may be polluting the river collectively. When point-source pollution enters the environment, the place most affected is usually the area immediately around the source. For example, when a tanker accident occurs, the oil slick is concentrated around the tanker itself and, in the right ocean conditions, the pollution disperses the further away from the tanker you go. This is less likely to happen with nonpoint source pollution which, by definition, enters the environment from many different places at once.

Sometimes pollution that enters the environment in one place has an effect hundreds or even thousands of miles away. This is known as transboundary pollution. One example is the way radioactive waste travels through the oceans from nuclear reprocessing plants in England and France to nearby countries such as Ireland and Norway.

How do we know when water is polluted? Some forms of water pollution are very obvious: everyone has seen TV news footage of oil slicks filmed from helicopters flying overhead.

Water pollution is usually less obvious and much harder to detect than this. But how can we measure water pollution when we cannot see it? How do we even know it's there? There are two main ways of measuring the quality of water. One is to take samples of the water and measure the concentrations of different chemicals that it contains. If the chemicals are dangerous or the concentrations are too great, we can regard the water as polluted.

Measurements like this are known as chemical indicators of water quality. Another way to measure water quality involves examining the fish, insects, and other invertebrates that the water will support. If many different types of creatures can live in a river, the quality is likely to be very good; if the river supports no fish life at all, the quality is obviously much poorer. Measurements like this are called biological indicators of water quality. What are the causes of water pollution?

Most water pollution doesn't begin in the water itself. Take the oceans: around 80 percent of ocean pollution enters our seas from the land. When farmers fertilize the fields, the chemicals they use are gradually washed by rain into the groundwater or surface waters nearby. Sometimes the causes of water pollution are quite surprising. Chemicals released by smokestacks chimneys can enter the atmosphere and then fall back to earth as rain, entering seas, rivers, and lakes and causing water pollution.

That's called atmospheric deposition.

Water pollution - Wikipedia

Water pollution has many different causes and this is one of the reasons why it is such a difficult problem to solve. Sewage With billions of people on the planet, disposing of sewage waste is a major problem. Water stored underground in aquifers is known as groundwater.

Aquifers feed our rivers and supply much of our drinking water. They too can become polluted, for example, when weed killers used in people's gardens drain into the ground. Groundwater pollution is much less obvious than surface-water pollution, but is no less of a problem.

In , a study in Iowa in the United States found that over half the state's groundwater wells were contaminated with weed killers. You might think things would have improved since then, but, two decades on, all that's really changed is the name of the chemicals we're using.

Today, numerous scientific studies are still finding weed killers in groundwater in worrying quantities: Surface waters and groundwater are the two types of water resources that pollution affects. There are also two different ways in which pollution can occur. If pollution comes from a single location, such as a discharge pipe attached to a factory, it is known as point-source pollution. Other examples of point source pollution include an oil spill from a tanker, a discharge from a smoke stack factory chimney , or someone pouring oil from their car down a drain.

A great deal of water pollution happens not from one single source but from many different scattered sources. This is called nonpoint-source pollution. Point-source pollution comes from a single, well-defined place such as this pipe. Nonpoint-source pollution comes from many sources. All the industrial plants alongside a river and the ships that service them may be polluting the river collectively. When point-source pollution enters the environment, the place most affected is usually the area immediately around the source.

For example, when a tanker accident occurs, the oil slick is concentrated around the tanker itself and, in the right ocean conditions, the pollution disperses the further away from the tanker you go.

This is less likely to happen with nonpoint source pollution which, by definition, enters the environment from many different places at once. Sometimes pollution that enters the environment in one place has an effect hundreds or even thousands of miles away. This is known as transboundary pollution. One example is the way radioactive waste travels through the oceans from nuclear reprocessing plants in England and France to nearby countries such as Ireland and Norway.

Some forms of water pollution are very obvious: Water pollution is usually less obvious and much harder to detect than this. But how can we measure water pollution when we cannot see it? How do we even know it's there? There are two main ways of measuring the quality of water. One is to take samples of the water and measure the concentrations of different chemicals that it contains. If the chemicals are dangerous or the concentrations are too great, we can regard the water as polluted.

Measurements like this are known as chemical indicators of water quality. Another way to measure water quality involves examining the fish, insects, and other invertebrates that the water will support.

If many different types of creatures can live in a river, the quality is likely to be very good; if the river supports no fish life at all, the quality is obviously much poorer. Measurements like this are called biological indicators of water quality.

Most water pollution doesn't begin in the water itself. Take the oceans: When farmers fertilize the fields, the chemicals they use are gradually washed by rain into the groundwater or surface waters nearby. Sometimes the causes of water pollution are quite surprising. Chemicals released by smokestacks chimneys can enter the atmosphere and then fall back to earth as rain, entering seas, rivers, and lakes and causing water pollution.

That's called atmospheric deposition. Water pollution has many different causes and this is one of the reasons why it is such a difficult problem to solve. With billions of people on the planet, disposing of sewage waste is a major problem. According to figures from the World Health Organization the most recent available at the time this article was updated in , some 2. Sewage disposal affects people's immediate environments and leads to water-related illnesses such as diarrhea that kills , children under five each year.

In developed countries, most people have flush toilets that take sewage waste quickly and hygienically away from their homes. Yet the problem of sewage disposal does not end there.

When you flush the toilet, the waste has to go somewhere and, even after it leaves the sewage treatment works, there is still waste to dispose of.

Sometimes sewage waste is pumped untreated into the sea. Until the early s, around 5 million tons of sewage was dumped by barge from New York City each year. In early , it was reported that the tiny island of Guernsey between Britain and France has decided to continue dumping 16, tons of raw sewage into the sea each day.

In theory, sewage is a completely natural substance that should be broken down harmlessly in the environment: When people are sick with viruses, the sewage they produce carries those viruses into the environment.

It is possible to catch illnesses such as hepatitis, typhoid, and cholera from river and sea water. During crop-spraying, some chemicals will drain into the soil. Eventually, they seep into rivers and other watercourses.

Suitably treated and used in moderate quantities, sewage can be a fertilizer: The trouble is, sewage is often released in much greater quantities than the natural environment can cope with. Chemical fertilizers used by farmers also add nutrients to the soil, which drain into rivers and seas and add to the fertilizing effect of the sewage.

Together, sewage and fertilizers can cause a massive increase in the growth of algae or plankton that overwhelms huge areas of oceans, lakes, or rivers. This is known as a harmful algal bloom also known as an HAB or red tide, because it can turn the water red. It is harmful because it removes oxygen from the water that kills other forms of life, leading to what is known as a dead zone. The Gulf of Mexico has one of the world's most spectacular dead zones.

Each summer, according to studies by the NOAA , it grows to an area of around — square miles 14,—15, square kilometers , which is about the same size as the state of Connecticut. A few statistics illustrate the scale of the problem that waste water chemicals washed down drains and discharged from factories can cause. Around half of all ocean pollution is caused by sewage and waste water.

Each year, the world generates perhaps 5—10 billion tons of industrial waste, much of which is pumped untreated into rivers, oceans, and other waterways. However, there have been major improvements in waste water treatment recently.

Factories are point sources of water pollution, but quite a lot of water is polluted by ordinary people from nonpoint sources; this is how ordinary water becomes waste water in the first place. Virtually everyone pours chemicals of one sort or another down their drains or toilets.

Even detergents used in washing machines and dishwashers eventually end up in our rivers and oceans. So do the pesticides we use on our gardens. A lot of toxic pollution also enters waste water from highway runoff. Highways are typically covered with a cocktail of toxic chemicals—everything from spilled fuel and brake fluids to bits of worn tires themselves made from chemical additives and exhaust emissions. When it rains, these chemicals wash into drains and rivers.

It is not unusual for heavy summer rainstorms to wash toxic chemicals into rivers in such concentrations that they kill large numbers of fish overnight.

Legislation on water pollution control

It has been estimated that, in one year, the highway runoff from a single large city leaks as much oil into our water environment as a typical tanker spill. Some highway runoff runs away into drains; others can pollute groundwater or accumulate in the land next to a road, making it increasingly toxic as the years go by.

Detergents are relatively mild substances. At the opposite end of the spectrum are highly toxic chemicals such as polychlorinated biphenyls PCBs. They were once widely used to manufacture electronic circuit boards , but their harmful effects have now been recognized and their use is highly restricted in many countries. Nevertheless, an estimated half million tons of PCBs were discharged into the environment during the 20th century.

They were carried there through the oceans, thousands of miles from where they originally entered the environment. Although PCBs are widely banned, their effects will be felt for many decades because they last a long time in the environment without breaking down. Another kind of toxic pollution comes from heavy metals , such as lead , cadmium, and mercury.

Lead was once commonly used in gasoline petrol , though its use is now restricted in some countries. Mercury and cadmium are still used in batteries though some brands now use other metals instead. Until recently, a highly toxic chemical called tributyltin TBT was used in paints to protect boats from the ravaging effects of the oceans.

Ironically, however, TBT was gradually recognized as a pollutant: The best known example of heavy metal pollution in the oceans took place in when a Japanese factory discharged a significant amount of mercury metal into Minamata Bay, contaminating the fish stocks there. It took a decade for the problem to come to light. By that time, many local people had eaten the fish and around were poisoned.

Hundreds of people were left dead or disabled. People view radioactive waste with great alarm—and for good reason. At high enough concentrations it can kill; in lower concentrations it can cause cancers and other illnesses. The biggest sources of radioactive pollution in Europe are two factories that reprocess waste fuel from nuclear power plants: Both discharge radioactive waste water into the sea, which ocean currents then carry around the world.

Countries such as Norway, which lie downstream from Britain, receive significant doses of radioactive pollution from Sellafield.

The Norwegian government has repeatedly complained that Sellafield has increased radiation levels along its coast by 6—10 times.

Both the Irish and Norwegian governments continue to press for the plant's closure. Oil-tanker spills are the most spectacular forms of pollution and the ones that catch public attention, but only a fraction of all water pollution happens this way. When we think of ocean pollution, huge black oil slicks often spring to mind, yet these spectacular accidents represent only a tiny fraction of all the pollution entering our oceans. Even considering oil by itself, tanker spills are not as significant as they might seem: The biggest oil spill in recent years and the biggest ever spill in US waters occurred when the tanker Exxon Valdez broke up in Prince William Sound in Alaska in Around 12 million gallons 44 million liters of oil were released into the pristine wilderness—enough to fill your living room times over!

Estimates of the marine animals killed in the spill vary from approximately sea otters and 34, birds to as many as sea otters and , sea birds. Several billion salmon and herring eggs are also believed to have been destroyed. If you've ever taken part in a community beach clean, you'll know that plastic is far and away the most common substance that washes up with the waves.

There are three reasons for this:

TOP Related


Copyright © 2019 mtn-i.info.
DMCA |Contact Us