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Organisms and Environment - I

Organisms and Environment

Solid Waste

  • Consists of all the unwanted undesired materials thrown into the dustbin
  • It may be composed of biodegradable or non-biodegradable wastes.
  • Open dumps used for disposing solid waste serves as breeding ground for rats and flies. Therefore, sanitary landfills are used as a substitute for these.
  • Biodegradable wastes can be either aerobically on anaerobically broken down using microbes. The non-biodegradable waste can be recycled, reused, or dumped in landfills.
  • Hospital wastes also contain hazardous materials, which have to be disposed properly. Hospital wastes are generally incinerated.
  • Irreparable computers and other electronic goods make up e-wastes, which are either dumped in land fills or are incinerated. E-waste can be recycled also to recover metals such as copper, iron, silicon, gold, etc.
  • To use the plastic waste in an efficient way, polyblend, a fine powder of recycled modified plastic, has been developed. When polyblend is mixed with bitumen, it can be used to lay roads with greater water repellent capacity and greater life.
Phosphorus cycle is a sedimentary cycle.

Phosphorus Cycle

  • Phosphorus is an important constituent of cell membranes, nucleic acids, and cellular energy transfer systems.

  • Rocks contain phosphorus in the form of phosphate.

  • When rocks are weathered, some of the phosphate gets dissolved in the soil solution and is absorbed by plants.

  • The consumers get their phosphorus from the plants.

  • Phosphorus returns back to the soil by the action of phosphate-solubilising bacteria on dead organisms.


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  • The increased use of pesticides, fertilizers for increasing the produce has led to eutrophication and biomagnifications in water sources.

  • In order to check this, the concept of organic farming is increasingly becoming popular. In this technique, instead of using chemical fertilizers and pesticides, natural materials and techniques such as organic manure (cow dung manure), compost, biological pest control, and crop rotation are used. This leads to a balanced soil, which does not cause soil infertility, but causes the rejuvenation of the soil.

Radioactive Wastes

  • Nuclear energy is a non-polluting energy except the threats posed by accidental leakage and difficult disposal of radioactive waste.

  • Radioactive substances cause severe damages such as mutations and cancer in lower doses and higher doses can be lethal.

  • Radioactive wastes should be suitably pre-treated in shielded containers buried under rock surfaces about 500 m under the earth’s surface.

Improper Utilisation of Resources

  • Natural resources can get degraded by their improper use.

    • Soil erosion and desertification − Over-cultivation, overgrazing, deforestation, and poor irrigation techniques lead to soil erosion and desertification.

    • Water logging and soil salinity - Lack of proper drainage leads to water logging, which affects the crops and also leads to increase in the salinity of the soil.

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