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Monday, April 13, 2009

water pollution
People cause water pollution when they dump wastes such as chemicals, metals, and oil into oceans, lakes, streams, and so on. Water pollution is a serious problem in Canada and the US. When we pollute water, it can look dirty and smell really bad. Sometimes polluted water contains chemicals and germs that not only kills the aquatic ecosystem, but can make people ill and in some cases, death.

Green water has too many tiny plants called algae growing in it. When algae die, they decompose and use up oxygen that animals need to survive.

Foam or suds in the water which comes from detergents from homes or factories. If the water smells rotten, it might mean sewage has been dumped nearby.

It is difficult to identify all polluted water by appearance because sometimes polluted water doesn't shows no signs.

The Pollution Problem



It is easy to dispose of waste by dumping it into a river or lake. In large or small amounts, dumped intentionally or accidentally, it may be carried away by the current, but will never disappear. It will reappear downstream, sometimes in changed form, or just diluted. Freshwater bodies have a great ability to break down some waste materials, but not in the quantities discarded by today's society. This overload that results, called pollution, eventually puts the ecosystem out of balance.
Sometimes nature itself can produce these imbalances. In some cases, the natural composition of the water makes it unfit for certain uses: e.g., water flowing in the highly saline terrain of the prairies or gushing from highly mineralized springs in some parts of the country cannot sustain fish populations.
But most often our waterways are being polluted by municipal, agricultural and industrial wastes, including many toxic synthetic chemicals which cannot be broken down at all by natural processes. Even in tiny amounts, some of these substances can cause serious harm.
The Great Lakes, the Fraser River, and the St. Lawrence River are and continue to be seriously contaminated by such toxic chemicals.

Mercury

Mercury is a toxic heavy metal, which, when ingested, can cause serious neurological damage, particularly to developing fetuses, infants and children. Consequences of exposure to mercury include permanent and irreversible developmental delaysin learning to walk and talk, in coordination, visual loss, cerebral palsy, mental retardation, abnormal heart rhythms, abnormal reflexes, liver digestion and gastrointinal disturbances. People most at risk include women of childbearing age, pregnant women, nursing mothers, and subsistence fisher people.
Mercury makes its way into our diets primarily by first being emitted into the air and then washed into lakes and streams by rain and snow, where it reacts with bacteria to form organic mercury, the form most toxic to humans.
Mercury comes from coal and oil (32.8 %) burning electric power plants, municipal waste incinerators (18.7%), commercial and industrial boilers (10.1%) hazardous waste incinerators (4.4%) and manufacturing plants (10 %).

The release of mercury into the environment is harmful to both the ecosystem and human health. The comprehensive phase out of mercury's release is ultimately important because of its ability to persist in the environment for a long time. It can then bioaccumulate in aquatic food chains, to the point that consumption of fish is hazardous to birds, mammals and humans. There has been groups that has been working hard to achieve full mercury phase out, and has had many successes to date.

Cadmium

Cadmium is one group of elements known as "heavy metals". They are pollutants produced by industries and mining which can be dangerous to humans and animals even in very small quantities. In the case of cadmium, for example, the World Health Organization (WHO) recommends that drinking water that contains less then 0.000175 thousandths of an ounce of cadmium per quart (one quarter of a gallon). Concentrations greater than this cause disease of the kidneys and reproductive organs in humans.

Lead (PB)

Exposure to lead occurs mainly through the inhalation of air and the ingestion of lead in food, water, soil, and/or dust. It accumulates in the blood, bones and soft tissues. Because it is not readily excreted, lead can also adversely affect the kidneys, live, the nervous system and other organs.

Excessive exposure to lead may cause neurological impairments such as seizures, mental retardations and/or behavioral disorders. At low doses, fetuses and children often suffer from central nervous system damage. Recent studies also show that lead may be a factor is high blood pressure and subsequent heart disease.

What are the main source of water pollution?

The main source of water pollution is sewage, industries, and agriculture. Sewage is human wastes and water that has been used for bathing and cleaning clothes.
Industry puts three to four more times as many pollutants into water as all of our sewage systems do.
Chemicals and other wastes from farms also pollute our water.

Some farmers use chemical fertilizer to help their crops grow. They also use pesticides to kill pests such as insects and weeds. Rain water can carry these chemicals from the farmland into streams, and rivers. Animal wastes from farms also add to water pollution.

Aquatic ecosystems



In nature nothing exists alone. Living things relate to each other as well as to their non-living, but supporting, environments.
These complex relationships are called ecosystems. Each body of water is a delicately balanced ecosystem in continuous interaction with the surrounding air and land.

Whatever occurs on the land and in the air also affects the water. If a substance enters a river or lake, the water can purify itself biologically — but only to a degree. Whether it is in the smallest stream or lake — or even in the mighty oceans — the water can absorb only so much. It reaches a point where the natural cleaning processes can no longer cope.

How does pollution affect marine life?



People dump hazardous materials into the ocean to get rid of them. Sewage and waste from factories and cities can reach the ocean. This pollution is very harmful. It can kill the plants and animals living in the ocean. Dangerous chemicals like mercury kill the aquatic environment very quickly. Over 360 chemical compounds that have been identified in the Great Lakes. Many are persistent toxic chemicals such as DDT, and mercury potentially dangerous to humans and already destructive to the aquatic ecosystems.

For example, various species of fish now suffer from tumors and lesions, and their reproductive capacities are decreasing. Populations of fish consuming birds and mammals also seem to be on the decline. Of the ten most highly valued species of fish in Lake Ontario, seven have now almost totally vanished.

How to tell if a river/ lake is polluted



· If it has an uncontrolled amount of organic material such as sewage, milk, silage, liquids etc. that is affecting a waterway, the main sign that the water is polluted is that the water would be choked with vegetation.

· In the case of acid rain, the affect on the water is quite the opposite. The water will appear to be crystal clear. This is because the water is too acidic for fish etc. to live in.

· There may be bad smells where toxic waste is involved



question

What is water pollution?
What is the effect of water pollution?
What are the causes of water pollution?

answer

Water pollution is the contamination of water bodies such as lakes, rivers, oceans, and groundwater caused by human activities, which can be harmful to organisms and plants that live in these water bodies. It occurs when pollutants are discharged directly into water bodies without treating it first.

In rivers, oceans and seas, water pollution effects flora and fauna in them. Further, the birds and animals that consume this contaminated food supply can perish. Blood diseases, nervous system disorders and heart diseases are some of the effects of water pollution. Many toxins in polluted water lead to cancer. Rarely, the body's chromosomal makeup can be altered. Some of the less potent effects are skin lesions, vomiting and diarrhea.


People cause water pollution when they dump wastes such as chemicals, metals, and oil into oceans, lakes, streams, and so on

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