State and explain the effects of population growth on the environment.

1) Air pollution
- Chemicals such as carbon monoxide from motor vehicles and other gases from industries and factories (including sulphur oxide, nitrogen oxide and hydrocarbonates) are continuously discharged into the atmosphere.Petroleum refineries and chemical plants (industries) among others add toxic substances to the air.
- Air pollution is a threat to health as it causes heart and lung diseases,respiratory diseases such as asthma and can cause cancer.

2) Water pollution
- Industries dissipate waste water and individual waste into the drainage system .Water masses have unfortunately become dumping ground for all sorts of human waste.
- Population growth has also led to the need for increased agricultural production and thus has resulted in heavier application of pesticides, herbicides and fertilizers.
- As a result, more pollutants have found their way into streams, rivers, lakes, seas and even underground water and this has become a real health hazard. In a number of instances, agriculture today can be considered ecologically hazardous

3. Solid waste
One of the major problems facing most cities of the world today, including Nairobi , is lack of space for the hygienic disposal of solid waste. Solid waste has become an aesthetic disaster. Further, water percolating through burnt solid waste soon becomes polluted and provides breeding grounds for disease- bearing organizations such as flies, rats and cockroaches.

4. Geo-ecological hazards
Whenever there is human concentration, the surface of the earth is disfigured by wasteful methods of cultivation,overgrazing, sheer movement of animals and deforestation.These interfere with the natural ecosystem.

5. Pollution of heavy metals
Through the industrial processes, metals likes mercury find their way into lakes and rivers thereby polluting drinking water. Mercury and lead poisoning have disastrous effects on man’s health. They also affect aquatic life.

6. Radiation.
Certain machines and substances used by man in relation to health, transport and nutritional requirements have proved detrimental to health. X-ray machines, certain chemicals and foods can have serious radioactive effects on man eg. Genetic defects, cancer,stillbirth, etc.

7. Noise pollution
Amplified music and supersonic aircraft produce noise that is detrimental to man’s hearing. Excessive noise can cause temporary and permanent loss of hearing.

8) Pesticides and nitrogen
In a number of instancesagriculture today can also be considered ecologically hazardous. Pesticides often kill a higher proportion of the non-targetpopulation. Pesticides with persistent effects -DDT forinstance - have been proved to kill or reduce the reproductive capacity in sea animals such as fish and other organisms in the soil and air.Soil treated with deadly and persistent poisons are causing a great concern among environmental biologists and ecologists. Constant use of such pesticides is certainly reducing soil fertility.
The use of herbicides as a substitute for farm machinery and labour in cultivating crops has also greatly affected the environment. Though their direct toxicity on animals may be low, herbicides have a great impact on animal population as they modify and reduce the plant population on which animals depend.
The excessive use of artificial fertilizers in the form of nitrogen and phosphates is also being questioned. Fears are expressed in regard to the effects that they have on the soil ecosystem and subsequent fertility and productivity. Where fertilizers have been used in Kenya for a long time (such as Kitale), the original composition of the soil has been altered. It does not yield abundant crops unless farmers continue to use fertilizers. Adding nitrogen to water bodies through the use of fertilizers in farming leads to a contamination that cannot be removed by either boiling or chlorination. The dangerous chemicals that the water contains will not be removed or broken down.

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Kavungya answered the question on April 19, 2019 at 08:03