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  • Water pollution and its harm

    Release time: 2019-10-29 09:53:59

    What is water pollution? What are the main sources of water pollution?  
    When dirty and harmful substances enter clean water, water pollution happens.  
    The main sources of water pollution are:
    Untreated industrial wastewater;
    Untreated domestic sewage;
    • farmland sewage with large quantities of fertilizers, pesticides and herbicides;
    • industrial waste and domestic waste stacked on the riverside;
    Soil and water loss;
    Mining sewage.  
    What harm can water pollution bring?  
    The following are the substances that cause major water pollution, their sources and hazards.
    1) dead organic matter:
    Example: untreated municipal sewage, papermaking sewage, agricultural sewage, urban refuse
    Hazards:
    Consumption of dissolved oxygen in water endangers the survival of fish.  
    It causes the lack of oxygen in water, resulting in the death of microorganisms that need oxygen. It is these aerobic microbes that can decompose organic matter and maintain the self purification ability of rivers and streams. The consequences of their death are rivers and streams, darkening, odour, toxins accumulating, hurting people and animals.  
    2) organic and inorganic chemicals:
    Examples are: chemical industry, pharmaceutical plant emissions, paper making, tannery wastewater, building decoration, dry cleaning industry, chemical lotion, agricultural insecticide, herbicide.
    Hazards:
    Most organic chemicals are toxic. They enter rivers and lakes and poison or poison aquatic organisms, causing ecological damage.  
    Some organic chemicals will accumulate in aquatic organisms and cause poisoning after human consumption.  
    The water polluted by organic chemicals is hard to be purified, and the safety and health of human drinking water are threatened.  
    3) phosphorus:
    Source example: phosphorus containing laundry powder, a large number of phosphorus and nitrogen fertilizers.
    Hazards:
    Causing algae blooms in water. Because phosphorus is an important element for all biological growth. Phosphorus is seldom found in nature. After the phosphorous wastewater discharged into the lake by human beings, the algae in the lake will be enriched and enriched rapidly (called water eutrophication).  
    Causing massive bacterial multiplication in the lake. The longer the thicker the algae is, the more it is thicker. Finally, some of them are under the surface of the water. The bacteria at the bottom of the lake proliferate rapidly with dead algae as nutrients. It causes fish to die and lakes to die. A large number of bacteria consume the oxygen in the water, make the lake water become anoxic, and the fish that depend on oxygen live to die. Then the bacteria will also die from lack of oxygen. Eventually, the lake will become old and dead.  
    It can threaten the eutrophication of coastal waters in the tropics, which is similar to the upper velocity.  
    4) Petrochemical detergent
    Source examples: tableware detergent used by families and restaurants.
    Hazards:
    Most of the washing spirits are products of petrochemical industry, which are difficult to degrade. They will not only pollute the water seriously, but also accumulate in aquatic products.  
    5) heavy metals (mercury, lead, cadmium, nickel, selenium, arsenic, chromium, thallium, bismuth, vanadium, gold, platinum, silver, etc.):
    Examples are: Mining and smelting process, industrial waste, tannery wastewater, textile mill wastewater, domestic waste (such as batteries, chemicals).
    Hazards:
    It has direct physiological toxicity to humans and animals.  
    By irrigating crops with heavy metals, crops can be polluted by heavy metals, resulting in the toxicity of agricultural products.  
    Deposited in the bottom of the river, the Gulf, through aquatic plants into the food chain, through fish and other aquatic products into the human body.  
    6) acids: (for example, sulphuric acid)
    Example: coal mine, other metal (copper, lead, zinc, etc.) mine waste, to discharge acid plant into the river.  
    Hazards:
    Poisoning plants in water.  
    It causes fish and other aquatic organisms to die.  
    It seriously destroys the ecosystem of streams, ponds and lakes.  
    6) suspended solids:
    Source: soil erosion, dumping rubbish into rivers
    Hazards:
    Reduce water quality and increase the difficulty and cost of purified water.  
    Modern domestic refuse has many undegradable components, such as plastic packaging materials. When they enter rivers, they are harmful not only to aquatic organisms but also to river courses.  
    7) oil substances:
    Source example: water mobile transport, oil tanker leakage
    Hazards:
    Destroy the ecological environment of aquatic organisms and reduce fishery production.  
    Pollute aquatic products and endanger human health.  

    The leakage of oil tankers on the ocean will cause a large number of marine animals (from fish and shrimp, seabirds to seals, sea lions, etc.) to die.