What is water pollution? What are the main sources of water pollution?

When dirty, harmful substances into clean water, water pollution occurred.

Water pollution are:

· The discharge of untreated industrial wastewater;

· The discharge of untreated domestic sewage;

· Extensive use of fertilizers, pesticides, irrigation and sewage herbicide;

· Stacked in riverside industrial waste and garbage;

· Soil erosion;

· Mine effluent.

Pollution will bring any harm?

Listed below are the main cause of water pollution substances, their sources, what harm:

1) Death of organic matter:

Source Example: municipal sewage, papermaking wastewater, agricultural runoff, urban garbage untreated

harm:

· Depletion of dissolved oxygen in the water, threatening the survival of fish.

· Causes the water of oxygen, resulting in the death of microorganisms need oxygen. And it is because of these aerobic microorganisms capable of decomposing organic matter, maintain rivers, streams of self-purification capacity. Consequences of their deaths are: rivers and streams black, stank, toxins accumulate, hurt people and animals.

2) organic and inorganic chemicals:

Source Example: chemical, pharmaceutical emissions, paper, wastewater, building renovation, the dry cleaning industry, chemical detergent, agricultural insecticides, herbicides

harm:

· Most of the organic chemicals are toxic, they enter rivers and lakes can poison or poisoned aquatic life, causing ecological damage.

• Some organic chemicals can accumulate in aquatic organisms, resulting in people after eating poisoned.

· Organic chemicals are difficult to purify contaminated water, safe drinking water and human health is threatened.

3) P:

Source example: a large administration phosphorus washing powder, phosphorus and nitrogen fertilizers

harm:

· Cause algae blooms. Because phosphorus is an important element needed for all biological growth. In nature, phosphorus rarely. Phosphorus discharge of human sewage into the lake after, the lake will get rich in nutrients algae grow sharply (called eutrophication).

· Causes large population of bacteria in the lake. Soaring algae in the water longer and thicker, and finally there is pressure in the under part of the surface, due to the microscopic sunshine and death. Lake bacterial death algae as a nutritional, rapid proliferation. · Causing fish kills, lakes death. Proliferate bacteria consume oxygen in the water, so the water becomes oxygen, oxygen-dependent survival of fish kills, and then the bacteria will die from lack of oxygen, ultimately lake aging, death.

· Can cause a similar situation with the speed of eutrophication threat to seaside waters in tropical regions.

4) petrochemical detergents

Source Example: tableware homes and restaurants extensive use of detergent behind

harm:

· Most detergent behind are petrochemical products, difficult to degrade, into the river will not only seriously polluted water bodies, and will accumulate in aquatic products, there will be poisoning after eating.

5) heavy metals (mercury, lead, cadmium, nickel, selenium, arsenic, chromium, thallium, bismuth, vanadium, gold, platinum, silver, etc.):

Source Example: mining and smelting processes, industrial waste, wastewater, textile wastewater, domestic waste (such as batteries, chemical-like product)

harm:

• For people, animals have a direct physiological toxicity.

• Use water to irrigate crops containing heavy metals, can crop contamination by heavy metals, resulting in toxic agricultural products.

· Deposition in the river, bay, enter the food chain through aquatic plants, fish and other aquatic products enter the body through.

6) acids: (e.g., sulfuric acid)

Source Example: coal, other metals (copper, lead, zinc, etc.) mine waste, emissions into rivers acid plant.

harm:

· Poisoned water plants.

· Cause of death of fish and other aquatic organisms.

Severe damage to the ecological system streams, ponds and lakes.

6) suspension:

Source Example: soil erosion, the dumping of garbage into the river

harm:

• Reduce water quality, increase the difficulty and cost of purifying water.

· There are many modern garbage difficult to degrade components, such as plastic packaging materials. After they enter the river, is not only very harmful to aquatic organisms (after eating death), and will block the river.

7) oil substances:

Source Example: Water motorized transport, tanker leak

harm:

· Destruction of the ecological environment of aquatic organisms that fishery production.

· Contaminated aquatic food, endangering people's health.

· Tanker leaks will cause a large number of marine animals (from fish, sea birds to seals, sea lions, etc.) died on the ocean.